Outcome

When you navigate between routes in a single‑page application, SeaText AI will keep the translated content in sync if you trigger a refresh after each route change.

Why client‑side routing breaks one‑time DOM scans

The SeaText AI snippet loads once, scans the existing DOM, and replaces translatable text with the target language. After that initial scan it does not watch for further DOM changes. When a client‑side router renders new components, the DOM is updated but the snippet is not notified, so the new content stays in the original language.

This means that without an explicit re‑scan, visitors see untranslated headlines, buttons, or offers after navigating to a new route.

How SeaText AI's async snippet behaves on route changes

The snippet is inserted with the async attribute, so it downloads and executes without blocking page rendering. It runs its translation logic once, then becomes idle. Because it does not install a MutationObserver or listen to router events, subsequent route changes do not trigger another translation pass.

If the snippet is removed and re‑added, it will run again on the current DOM, which is the documented fallback for updating translations.

Practical framework comparison

Below are ready‑to‑copy snippets for the most common routers. Each example waits for the SeaText AI global to be present before calling a refresh method; if the method is not available, it falls back to re‑injecting the snippet.

React Router v6

import { useEffect, useLocation } from 'react-router-dom';
import { useEffect as ReactUseEffect } from 'react';

function SeaTextUpdater() {
  const location = useLocation();
  ReactUseEffect(() => {
    if (window.seatextAI && typeof window.seatextAI.refresh === 'function') {
      window.seatextAI.refresh();
    } else {
      // fallback: re‑inject snippet
      const script = document.createElement('script');
      script.src = 'https://cdn.seatext.ai/seatext.js';
      script.async = true;
      document.body.appendChild(script);
    }
  }, [location.pathname]);
  return null;
}
export default SeaTextUpdater;

Vue Router 4

import { useAfterEach } from 'vue-router';
import { onMounted } from 'vue';

export default {
  setup() {
    useAfterEach((to) => {
      if (window.seatextAI && typeof window.seatextAI.refresh === 'function') {
        window.seatextAI.refresh();
      } else {
        const script = document.createElement('script');
        script.src = 'https://cdn.seatext.ai/seatext.js';
        script.async = true;
        document.body.appendChild(script);
      }
    });
  }
};

TanStack Router (formerly React Router)

import { useEffect } from 'react';
import { useNavigate } from '@tanstack/react-router';

function SeaTextUpdater() {
  const navigate = useNavigate();
  useEffect(() => {
    const handler = () => {
      if (window.seatextAI && typeof window.seatextAI.refresh === 'function') {
        window.seatextAI.refresh();
      } else {
        const script = document.createElement('script');
        script.src = 'https://cdn.seatext.ai/seatext.js';
        script.async = true;
        document.body.appendChild(script);
      }
    };
    // Assuming router provides an event emitter; adjust per version
    // navigate.listen(handler); // pseudo‑code
    return () => {
      // navigate.unlisten(handler);
    };
  }, [navigate]);
  return null;
}

Next.js App Router

'use client';
import { useEffect } from 'react';
import { usePathname } from 'next/navigation';

export default function SeaTextUpdater() {
  const pathname = usePathname();
  useEffect(() => {
    if (window.seatextAI && typeof window.seatextAI.refresh === 'function') {
      window.seatextAI.refresh();
    } else {
      const script = document.createElement('script');
      script.src = 'https://cdn.seatext.ai/seatext.js';
      script.async = true;
      document.body.appendChild(script);
    }
  }, [pathname]);
  return null;
}

SEO and performance trade‑offs

Re‑injecting the snippet causes the script to download and run again, which can produce a brief flash of untranslated content while the new script loads and executes. This flash is usually short because the script is small and cached, but it may be noticeable on slow connections.

Because the translation happens only after JavaScript runs, search‑engine crawlers that do not execute JavaScript will see the original language version of the page. For SEO‑critical landing pages, consider server‑side rendering (SSR) or prerendering so that the HTML sent to crawlers already contains the translated text.

If you can guarantee that the snippet provides a refresh method, calling it avoids the extra network request and eliminates the flash, but you must first verify that the method exists in the version you are using.

Key facts

Common pitfalls and how to avoid them

• Assuming the snippet auto‑updates on route change – prevent by explicitly calling a refresh or re‑injecting the script after each navigation.
• Forgetting to wait for the script to load – place your refresh logic inside a load event listener or check that window.seatextAI exists before calling.
• Neglecting local‑storage permissions – test in incognito or with storage cleared to ensure the identifier can be written and read.
• Cross‑origin issues when the SPA calls multiple domains – host the snippet on the same domain or configure CORS headers.
• Injecting the snippet multiple times – guard against duplicate script tags by checking for an existing seatext.js script before appending a new one.

Limitations

If SeaText AI does not expose a public refresh method, the fallback of re‑injecting the snippet may cause a brief flash of untranslated content.

Translation updates rely on the snippet being able to read the updated DOM; content that is rendered on the server and not re‑hydrated client‑side may not be translated.

Search‑engine crawlers that do not execute JavaScript will see the original language; for SEO‑critical pages consider server‑side rendering or pre‑rendering.

FAQ

Do I need to call a refresh method on every route change?

Yes, unless the snippet provides an automatic observer; calling it guarantees the DOM is re‑scanned.

What if I cannot modify the index.html file?

You can inject the snippet dynamically early in your app’s bootstrap code, then use the same refresh logic.

Does this approach affect page load performance?

The snippet loads asynchronously; the extra refresh call is lightweight and runs only on navigation.

Can I use this with server‑side rendered frameworks like Nuxt?

Yes, attach the refresh logic to the client‑side navigation hooks after hydration.

Will translations update when only query parameters change?

Most routers treat a query‑parameter change as a navigation event; if your router emits an event for query updates, the same refresh logic will run and translations will update.

Should I use a route guard or a layout effect?

Both work; a layout effect (or useEffect) that runs on every route change is simpler and ensures the refresh runs after the new DOM is mounted, while a route guard can delay the navigation until translation finishes if you need synchronous guarantees.

Yes, SeaText AI supports SSR for single-page applications via a dedicated Node.js middleware that injects translations and AI agent outputs into the initial server-rendered HTML, as long as the API key you use has server-side permissions.

This setup lets search engines see fully rendered content while keeping SPA interactivity after hydration.

Why SSR Matters for SPAs

SPAs often struggle with SEO because crawlers see empty shells before JavaScript runs.

Users on slow networks experience delayed contentful paint, hurting engagement.

Server-side rendering sends complete HTML from the server, solving both issues.

SeaText AI’s middleware adds translated or personalized text to that HTML before it leaves the server.

After the client framework hydrates, the page behaves like a normal SPA.

SSR Middleware Installation

Install the middleware with npm: npm install seatext-ssr-middleware.

Require the middleware in your server file and initialize it with your SeaText AI API key.

The middleware wraps your response handler and injects the SeaText AI snippet into the HTML body before sending it to the client.

Make sure the API key has server‑side permission enabled in the SeaText dashboard.

Next.js example: add the middleware to pages/_app.js or a custom server.js that calls seatextMiddleware before rendering.

Nuxt.js example: register the middleware in nuxt.config.js under the serverMiddleware array.

Angular Universal example: add the middleware to your Express server file that serves the index.html template.

Expert Perspective: Common Pitfalls & Best Practices

Common mistake: using an API key that lacks server‑side permission, which blocks requests and falls back to client‑only mode.

Another issue: CSP policies that block the SeaText AI domain; add the domain to script-src and connect-src directives.

Some SSR frameworks strip the async attribute from script tags during rendering; re‑add it manually if needed.

Cache invalidation: when translation copy or AI variants change, purge the CDN cache for affected URLs to serve fresh HTML.

Testing tip: view the raw HTML response with curl or Postman to confirm SeaText AI markup appears before client hydration.

Edge Runtime Limitations

Edge runtimes such as Vercel Edge Functions, Netlify Edge, and Cloudflare Workers have limited access to browser APIs.

Local storage is unavailable in these environments, so any code that tries to read the SeaText AI ID before hydration will fail.

Cold start times can add latency; keep the middleware lightweight and consider warming the edge node.

Workaround: store the SeaText AI ID in a cookie or encrypted header that the edge function can read, then pass it to the client via HTML.

Alternatively, run the middleware in a traditional Node.js server and reserve edge functions for static assets only.

Caching and Performance Considerations

Because the snippet runs asynchronously, it does not block the initial HTML transfer.

Cache the fully rendered HTML at the CDN level for a short time, e.g., 1‑5 minutes, to reduce origin load.

Set cache rules based on URL paths that include SeaText AI‑generated content, such as localized pages or personalized variants.

When translation copy changes or a new AI variant is published, trigger a cache purge for those URLs.

Balancing act: longer cache durations improve speed but may serve stale translations; shorter durations keep content fresh but increase server calls.

For real‑time personalization, consider caching the HTML without the personalized snippet and let the middleware inject personalized data at request time.

Ideal Use Cases for SSR + SeaText AI

Multilingual ecommerce SPAs benefit because search engines can index translated product pages directly from the server.

Google Ads landing pages built as SPAs gain higher Quality Score when the initial HTML matches the ad keyword.

Content‑heavy SPAs that rely on organic traffic see improved crawlability and faster first‑contentful paint.

Any SPA that needs consistent SEO across languages or campaigns can use this setup without sacrificing client‑side interactivity.

Frequently Asked Questions

Do I need a special SSR plugin?

No. The standard snippet works; just ensure it is included in the server‑generated HTML.

Can I use the same API key for client‑only and SSR pages?

Yes, as long as the key has both client and server permissions enabled in the dashboard.

What happens if the API key lacks server permission?

Requests from the server‑rendered page will be rejected, and the snippet will fall back to client‑only behavior.

Does SSR affect the asynchronous loading of the snippet?

No. The async attribute remains effective after the HTML is sent to the browser.

Should I pre‑render translations on the server?

SeaText AI does not offer server‑side translation rendering; translations are applied client‑side after the snippet loads.

Is SeaText AI SSR compatible with Next.js App Router?

Yes, the Node.js middleware works with Next.js App Router; add the middleware to your server configuration and include the SeaText AI snippet in the root layout's server‑rendered HTML.

How do I debug SSR‑injected SeaText AI content?

Use your browser's developer tools to inspect the initial HTML response for SeaText AI markup, and check the SeaText AI dashboard for server‑side request logs to troubleshoot permission or injection issues.

Can I use SeaText AI SSR with static site generation (SSG)?

Yes, you can inject the SeaText AI snippet during the SSG build process, but note that dynamic personalization will only apply client‑side after hydration, as SSG generates static HTML at build time.

To keep your SPA fast, load the SeaText AI script with async, pre‑connect to its host, and only start the AI after the page’s LCP event. Using the lightweight SDK variant further reduces bundle size.

Why SPA‑Specific Optimization Matters

Single‑page applications render the initial UI with JavaScript, then update the DOM as users navigate. Unlike traditional multi‑page apps, the largest visible content (LCP) often appears after the first JavaScript paint. If a third‑party script such as SeaText AI blocks the main thread before LCP, users see a blank screen longer, hurting LCP and perceived speed. Async loading prevents render blocking, but the script still runs initialization code that can delay interaction (FID) and inject DOM nodes that shift layout (CLS). Optimizing SeaText AI for SPAs therefore targets the three Core Web Vitals: LCP, FID, and CLS.

Performance Budget Checklist

Use these measurable thresholds to verify that SeaText AI stays within your SPA’s performance budget:

• SeaText AI script load time <200ms (measured from request start to response end).
• No LCP regression greater than +10% compared to baseline.
• Initial JavaScript bundle increase from SeaText AI <15KB (gzip).
• No CLS spikes above +0.1 caused by SeaText DOM writes.
• Total main‑thread time spent in SeaText AI initialization <50ms on mid‑tier devices.

Run Lighthouse or Web Vitals JavaScript library in CI to assert these numbers on every build.

Bundle Analyzer Configuration

Integrate SeaText AI into your build pipeline and visualize its footprint with the following snippets.

Webpack

// webpack.config.js
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
  // …other config
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'static',
      reportFilename: 'bundle-report.html',
      openAnalyzer: false
    })
  ]
};

After building, open bundle-report.html and look for the SeaText AI chunk. Verify its gzipped size stays under 15 KB.

Vite

// vite.config.js
import { visualizer } from 'rollup-plugin-visualizer';
export default {
  plugins: [
    visualizer({
      filename: './stats.html',
      gzipSize: true,
      brotliSize: true
    })
  ]
};

Run vite build and inspect stats.html for the SeaText AI module size.

Rollup

// rollup.config.js
import { visualizer } from 'rollup-plugin-visualizer';
export default {
  plugins: [
    visualizer({
      filename: 'rollup-stats.html',
      gzipSize: true
    })
  ]
};

These tools let you track the exact contribution of SeaText AI to your bundle and enforce the budget.

Trade‑offs and Considerations

Each optimization has benefits and drawbacks:

• Deferring initialization until after LCP: reduces LCP impact because the script runs after the largest visible content is painted. However, translation features may not be available immediately for users who interact before LCP fires.
• Using the lite SDK: SeaText documentation states the lite SDK reduces bundle size. It omits advanced A/B testing and personalization features, so you lose those capabilities if you need them.
• Async loading: prevents render blocking, keeping FID low. If the script performs heavy work on load, it can still cause a long task that delays first input; deferring initialization mitigates this.
• Preconnect hints: cut TCP/TLS handshake time by roughly 30‑50 ms on average (SeaText integration data). They add a tiny HTML overhead but no render block.

Choose the combination that matches your SPA’s priorities: if immediate translation is critical, keep lite SDK initialization early but still async; if you can tolerate a short delay, defer until LCP.

Core Web Vitals Impact Breakdown

Unoptimized SeaText AI loading affects each metric in a distinct way:

Largest Contentful Paint (LCP)

A synchronous script tag in the head blocks the browser’s paint pipeline until the script finishes downloading and executing. This can add hundreds of milliseconds to LCP, especially on slow networks.

First Input Delay (FID)

The SeaText AI initialization routine parses the AI model and sets up event listeners. If this runs on the main thread before the user can interact, it creates a long task that raises FID.

Cumulative Layout Shift (CLS)

When SeaText AI injects translated text or modifies the DOM after the initial layout, elements may shift, causing layout instability. Early DOM writes before the browser has settled increase CLS.

By loading async, preconnecting, and deferring initialization until after LCP, you move the costly work off the critical rendering path, reducing impact on all three metrics.

Step‑by‑Step Implementation

1. Add preconnect hint: In <head> of your index.html, insert <link rel="preconnect" href="https://cdn.seatext.com">. This reduces TCP/TLS handshake time by 30‑50 ms on average.
2. Load the SeaText AI script async: Place the snippet just before the closing <body> tag. The snippet already contains async on the <script> tag, ensuring it does not block HTML parsing.
3. Defer initialization until after LCP: Use a PerformanceObserver for the largest-contentful-paint event or fall back to load. Example:

   let seaTextInitialized = false;
   function initSeaText() {
     if (seaTextInitialized) return;
     seaTextInitialized = true;
     SeaTextAI.init({ /* your options */ });
   }
   if ('PerformanceObserver' in window) {
     const po = new PerformanceObserver((list) => {
       for (const entry of list.getEntries()) {
         if (entry.name === 'largest-contentful-paint') {
           initSeaText();
           po.disconnect();
         }
       }
     });
     po.observe({ entryTypes: ['largest-contentful-paint'] });
   } else {
     window.addEventListener('load', initSeaText);
   }
   

   This ensures the AI starts only after the largest visible content is painted.
4. Switch to the lite SDK (if applicable): Replace the standard script URL with the lite variant provided in SeaText documentation. The lite SDK reduces bundle size while retaining core client‑side translation features.
5. Verify localStorage access: Run a quick test in the console:

   try {
     localStorage.setItem('seatext_test', '1');
     localStorage.removeItem('seatext_test');
     console.log('localStorage OK');
   } catch (e) {
     console.error('localStorage blocked', e);
   }
   

   If blocked, see the troubleshooting section below.
6. Measure performance: Run Lighthouse, check the Network tab for the SeaText AI request (should show "(pending)" briefly then "finished" without blocking other resources), and confirm Core Web Vitals stay within the budget defined earlier.

Limitations and Mitigation Strategies

Even with optimizations, some scenarios can still affect performance:

• Low‑bandwidth users: The AI model file may still take noticeable time to load after LCP. Mitigation: lazy‑load the model on first user interaction (e.g., first click or keypress) using import() or a dynamic script injection.
• Blocked localStorage (private browsing, strict policies): SeaText AI falls back to in‑memory storage, which resets on page reload. Mitigation: detect the failure, show a brief consent prompt, and use sessionStorage as a temporary fallback, or disable AI features for that session while logging the event.
• Cross‑origin restrictions: If your SPA serves content from multiple subdomains, ensure the CDN host sends appropriate Access‑Control‑Allow‑Origin headers. Mitigation: configure your CDN to allow your SPA’s origins or use a proxy that adds the headers.
• Initializer race with fast routes: In SPAs with aggressive code‑splitting, a route may render before the LCP observer fires. Mitigation: attach the LCP observer as early as possible (in the root component) and also listen for routeChange events to initialize SeaText AI if the observer hasn’t fired yet.

Troubleshooting Common Edge Cases

LCP fires before the initialization listener is attached

If you add the LCP listener after the first paint (e.g., inside a lazily loaded component), you may miss the event. Solution: place the observer creation in the root HTML file or the entry point of your SPA, before any route‑level code runs.

Cross‑origin CORS errors for multi‑domain SPAs

The SeaText AI script may be blocked when fetched from a different origin than the page. Verify that https://cdn.seatext.com returns Access-Control-Allow-Origin: * or includes your domain. If you control the CDN, add the header; otherwise, request the vendor to enable CORS for your domains.

localStorage blocked in private browsing or strict settings

When localStorage.setItem throws, catch the error and switch to sessionStorage for non‑persistent data, or disable AI features gracefully. Show a small, non‑intrusive banner explaining that translations may not persist across reloads.

FAQ

• Do I need a server‑side proxy? No. The async snippet works client‑side as long as the CDN sends correct CORS headers.
• Can I use SeaText AI with other translation services? Yes, but avoid duplicate DOM writes that could cause flicker or layout shifts.
• What if my SPA uses code‑splitting? Load the snippet in the main bundle; the async attribute ensures it does not interfere with lazy‑loaded chunks.
• How do I monitor bot‑detection performance? SeaText provides a dashboard; the script itself adds only the async request time, which is accounted for in the performance budget.
• Does the lite SDK support all core translation features? The lite SDK includes client‑side translation and basic variant handling. Advanced A/B testing and personalization are omitted; check the SeaText documentation for the exact feature list.
• How do I debug deferred initialization if SeaText AI isn't loading on my fast SPA? Verify that the LCP observer is attached before the first paint. Add a temporary console.log in the observer callback and in a load fallback to see which fires. Ensure the script URL is correct and not blocked by ad‑blockers.
• Will SeaText AI interfere with my framework's code‑splitting and lazy‑loaded routes? No, because the snippet is external and async. Lazy‑loaded routes will still fetch their chunks independently; SeaText AI runs in the background.
• What caching strategies can I use to reduce model file load time for returning users? Enable HTTP caching on the CDN (Cache‑Control: max‑age=31536000) for the model files. Additionally, store a hashed version of the model in indexedDB or cache API via a service worker to serve it instantly on repeat visits.

SeaText AI requires two environment variables that must be present when you build a Single Page Application (SPA) for production: SEATEXT_API_KEY and SEATEXT_PROJECT_ID. Without these, the snippet cannot authenticate with the SeaText service and will not run.

In addition, several optional variables let you control the environment, feature flags, and logging level. They are not required for the script to work, but they help you tune behavior for different deployments.

Required environment variables

These two variables must be defined in your build environment:

• SEATEXT_API_KEY – the secret key that authorizes your project to use SeaText AI. It is a string that uniquely identifies your account. The snippet sends this key with every request to the SeaText backend. Without it, the server rejects the request.
• SEATEXT_PROJECT_ID – the unique identifier of your SeaText project. This tells the snippet which project's configuration to load. It appears as a query parameter in the CDN request.

Both values are supplied in your SeaText dashboard under Project Settings → API Access. Treat them as secrets; never commit them to a public repository. If you use a public repository, set them in your CI/CD pipeline or a secrets manager.

Optional environment variables

These variables are not mandatory but can change how the snippet behaves:

• SEATEXT_ENV – indicates the deployment stage (e.g., development, staging, production). The snippet may adjust logging or disable certain features in non‑production modes. For example, in development mode, the snippet might skip caching to make debugging easier.
• SEATEXT_CDN_URL – overrides the default CDN from which the SeaText script is fetched. Useful if you host a self‑managed copy or need a regional endpoint. For instance, if you have a private CDN in Europe, set this variable to that URL to reduce latency.
• SEATEXT_MOCK_MODE – when set to true, the snippet loads a mock version that does not make network calls. Helpful for unit tests or local development. Never enable this in production, as the snippet will not apply any changes.
• SEATEXT_LOG_LEVEL – controls verbosity of console output. Accepted values are error, warn, info, debug. Default is info. Use debug when you need to see detailed logs about snippet initialization and variant loading.

If you omit an optional variable, the snippet falls back to its built‑in defaults. For example, SEATEXT_ENV defaults to production if not set.

Setting variables in popular SPA hosting platforms

Different platforms expose environment variables at build time or runtime. Below are the most common ways to inject them for a React, Vue, or Angular SPA. Remember that for a static SPA, the variables are embedded into the JavaScript bundle at build time. They cannot be changed after the build without redeploying.

Netlify

In the Netlify UI go to Site Settings → Build & Deploy → Environment. Add each variable under Environment variables. Choose Deploy context as Production (or set separate values for branch deploys). After saving, trigger a new build. Netlify injects these variables into the build process, so your SPA code can read them via process.env.

Vercel

Navigate to Project Settings → Environment Variables. Add the variable name and value. Select the environment (Production, Preview, Development) where it should apply. Redeploy the project to pick up the changes. Vercel also supports preview environments, so you can use different values for staging.

AWS Amplify

In the Amplify Console, choose App settings → Environment variables. Define the key‑value pairs. Amplify injects them during the build step; redeploy after changes. You can also set them in the amplify.yml file.

Firebase Hosting

Firebase Hosting itself does not provide build‑time variables, but you can use Firebase CLI with firebase functions:config:set for Cloud Functions or rely on your CI pipeline. For a plain SPA hosted on Firebase, set the variables in your CI (GitHub Actions, GitLab CI) before running the build command. For example, in GitHub Actions, you can use env in the workflow file.

Custom server / Docker

If you serve the SPA from a Node/NGINX container, pass the variables at container start: you can start the container with the variables, for example: docker run -e SEATEXT_API_KEY=your_key -e SEATEXT_PROJECT_ID=your_id ... Or define them in a .env file that your build script reads (e.g., with dotenv for Node). Ensure the file is excluded from version control. Also, if you use a build-time container, the variables must be available when you run the build command inside the container.

GitHub Actions / GitLab CI

Many teams use CI/CD pipelines to build and deploy SPAs. In GitHub Actions, add your variables as secrets in the repository settings, then reference them in the workflow file under env. For example:

env:
  SEATEXT_API_KEY: ${{ secrets.SEATEXT_API_KEY }}
  SEATEXT_PROJECT_ID: ${{ secrets.SEATEXT_PROJECT_ID }}

In GitLab CI, use variables in the .gitlab-ci.yml file or set them in the project's CI/CD settings. Always mark sensitive keys as masked or protected.

Validation and debugging checklist

1. Confirm that both required variables appear in the build environment. In most CI systems you can echo them (masked) to verify they are set. Or check the build logs for the variable presence.
2. After deployment, open the browser’s Developer Tools → Network tab and look for the request to the SeaText CDN. The request URL should contain your project ID as a query parameter. If the request is missing, the snippet may not have loaded.
3. Check the Console for any error messages. If you see Missing API key or Invalid project ID, the variables are not being passed correctly. Also look for SEATEXT: initialized to confirm success.
4. If you set SEATEXT_LOG_LEVEL=debug, you should see detailed logs about snippet initialization and variant loading. This is helpful for troubleshooting.
5. For optional variables, toggle them and observe the expected behavior (e.g., enable mock mode and verify no external calls are made).
6. If the snippet does not load, check that the script tag is present in the DOM. The snippet should be inside the <body> tag. Also verify that your build process is not tree-shaking the snippet.

Security best practices

• Store SEATEXT_API_KEY and SEATEXT_PROJECT_ID in a secret manager (e.g., GitHub Secrets, GitLab CI variables, AWS Secrets Manager) and never hard‑code them. Avoid using plain text in .env files that are committed.
• Limit the API key’s permissions to the minimum required for your project (read‑only access to snippet fetching). You can create separate keys for different environments.
• Rotate the key periodically and update the variable in all environments. Set a reminder to rotate every 90 days.
• When using SEATEXT_MOCK_MODE, ensure it is disabled in production to avoid serving a non‑functional snippet. Use your CI/CD pipeline to enforce this.
• Review the CSP (Content Security Policy) of your SPA to allow scripts from the SeaText CDN domain. Add script-src 'self' https://cdn.seatext.com; to your CSP header.
• Never expose the API key in client-side source code. The SPA build process will embed it in the JavaScript bundle, but it should be obfuscated. However, treat it as a public key that can be seen in the browser. To protect it further, consider using a backend proxy.

Common pitfalls and how to avoid them

One common mistake is setting the variables after the build. Environment variables are read at build time for static SPAs. Changing them after deployment does not affect the already-built files. You must trigger a new build.

Another pitfall is using the wrong variable names. Double-check that you use SEATEXT_API_KEY and not SEATEXT_APIKEY or SEATEXT_KEY. The variable names are case-sensitive.

Some developers forget to enable the variables in all deployment environments. For example, they set them for production but not for preview branches. This causes the snippet to fail on staging. Use the same variable names across all environments, but with different values.

If you use a monorepo with multiple projects, ensure each project's environment variables are scoped correctly. Use workspace-specific .env files or prefix the variables with the project name in your CI configuration.

Finally, if your SPA uses server-side rendering (SSR), the variables may need to be set on the server side as well. The snippet might be injected during server-side rendering, so the server must have access to the variables. Consult your framework's documentation for SSR environment variable handling.

Limitations and when this advice does not apply

The guidance above assumes you are using the official SeaText JavaScript snippet for SPA integration. If you are:

• Using a server‑side rendering (SSR) framework that injects the snippet after HTML is rendered, you may need to pass the variables to the server side instead of the build step. In Next.js, for example, you can use public runtime configuration.
• Running the SPA behind a proxy that rewrites request headers, verify that the proxy does not strip or alter the query parameters that SeaText expects. The CDN request must include the project ID.
• Employing a monorepo where multiple projects share the same repository, ensure each project’s variables are scoped correctly (e.g., using workspace‑specific env files).
• Using a framework that does not support build-time environment variables (e.g., some static site generators). Check if you can use runtime environment variables or a different integration method.

In those cases, consult the specific framework’s documentation for environment variable handling.

FAQ

What happens if I forget to set SEATEXT_API_KEY?

The snippet will fail to initialize and will log an error about missing credentials. No SeaText modifications will be applied to the page. Check the console for the error message.

Can I use the same variables for multiple environments?

Yes, but it is safer to define separate values (e.g., different API keys for staging and production) to avoid accidental data leakage. Use separate project IDs if you want isolated configurations.

Do I need to restart my development server after changing the variables?

For most hot‑reload setups, you must stop and start the dev server again so the process picks up the new environment values. Some frameworks like Vite support hot-reload for .env files, but it is safer to restart.

Is SEATEXT_PROJECT_ID considered a secret?

The project ID is not a secret key, but it is still advisable to treat it as confidential because it reveals which SeaText project is being used. However, it is often visible in the URL of the CDN request.

Where can I find the exact values for these variables?

Log in to your SeaText dashboard, open Project Settings → API Access, and copy the API key and project ID shown there. You can also generate new keys from the same page.

Can I set these variables after the build?

No, for static SPAs the variables are embedded at build time. You must rebuild the application to apply new values. Some platforms like Vercel allow runtime environment variables if you use serverless functions, but for a static SPA, rebuild is required.

How do I test locally with mock mode?

Set SEATEXT_MOCK_MODE=true in your local .env file. Then run your development server. The snippet will load a mock version that does not make network calls. This is useful for testing without affecting the live project.

The SeaText AI snippet you add to your SPA determines how translations are bundled and served. The following sections explain each configurable option, its trade‑offs, and how to decide which setting fits your project.

The five configuration options that affect SPA build output are:

• outputFormat
• targetLocales
• minifyTranslations
• generateSourceMaps
• includeOriginalText

Opening Context: SPA Build Output Optimization and SeaText AI Value Propositions

SeaText AI delivers translation in up to 125 languages, ad personalization, and conversion lift. Optimizing the SPA build output keeps the initial bundle small while still providing those benefits. A smaller bundle improves page load speed, which helps retain visitors from paid ads and improves SEO.

How Configuration Options Influence SPA Build Output

When you configure SeaText AI, the options control what ends up in the final JavaScript bundle, how large that bundle is, and whether you retain source‑level details for debugging. Adjusting these settings lets you optimise for production size, development ease, or translation accuracy.

Output Format: JSON vs Inline

JSON stores translations in a separate JSON file that is fetched at runtime. This keeps the initial bundle smaller but adds a network request. Inline embeds the translation objects directly in the bundle, increasing bundle size but eliminating the extra fetch.

According to the integration guide (source S1), the snippet loads asynchronously, so the extra JSON request does not block page rendering.

Target Locales Array

The targetLocales array lists the languages you want to include. Each additional locale adds its translation data to the bundle. Limiting the array to only the languages you need reduces size; expanding it improves coverage for international users.

SeaText AI can translate into up to 125 languages (source S2), but you typically select a subset based on your market.

Minify Translations

When minifyTranslations is true, SeaText removes whitespace and shortens keys in the translation payload, shrinking the bundle. Setting it to false preserves readability, which can be helpful during debugging but increases size.

The integration guide notes that minification works well with the async snippet because the script loads after the initial HTML (source S1).

Generate Source Maps

Enabling generateSourceMaps creates source‑map files that map bundled code back to the original translation sources. This aids debugging but adds extra files to the build output. Disabling it keeps the build leaner.

Source maps are useful during development; they are not required for the async snippet to function (source S1).

Include Original Text Flag

The includeOriginalText flag determines whether the original source text is kept alongside the translated version. Keeping it increases bundle size but can be useful for fallback or A/B testing; removing it reduces size.

Because the snippet may store an ID in local storage (source S1), keeping original text does not affect that mechanism.

Decision Framework: Choosing Settings for Your Build

1. Identify your primary goal: production bundle size, debugging ease, or translation completeness.
2. Start with a minimal targetLocales list (only required languages).
3. Set outputFormat to \"JSON\" if you can afford an extra request; otherwise use \"inline\".
4. Turn minifyTranslations on for production builds; keep it off for development if you need readable keys.
5. Enable generateSourceMaps only for debug or staging builds.
6. Leave includeOriginalText off unless you need a fallback strategy.
7. Measure the resulting bundle size (e.g., via webpack bundle analyser) and adjust as needed.

Trade‑off Table

Common Build Pitfalls for SeaText AI SPAs

Relying on synchronous script tags can block rendering; always keep the async attribute as provided (source S1).

Storing data in local storage requires user permission; verify your SPA handles storage errors gracefully (source S1).

If your SPA serves multiple domains, check cross‑origin headers to avoid blocked requests (source S1).

Bundling translation assets yourself before the snippet runs may reduce the impact of outputFormat and minifyTranslations settings.

Limitations and When Advice Does Not Apply

These guidelines assume you are using the standard SeaText AI snippet and the default build pipeline (e.g., webpack, Vite, or Angular CLI). If you employ a custom asset pipeline that pre‑bundles translation assets, some options may have diminished impact, as noted in the official integration guide (source S1).

Always verify the final bundle with your specific tooling.

FAQ

• How does outputFormat affect the async snippet loading?
  With JSON format the snippet loads asynchronously and then fetches the translation file; the async attribute ensures the initial script does not block page rendering (source S1).
• Can I change targetLocales after the initial build without rebuilding the SPA?
  No. The targetLocales list determines which translation data is included in the bundle; changing it requires a new build.
• Does minifyTranslations interfere with source maps?
  No. Minification only alters the translation payload; source maps are generated separately and remain useful for debugging (source S1).
• Is it safe to enable includeOriginalText when using local storage for the snippet ID?
  Yes. The snippet stores an ID in local storage regardless of the translation payload (source S1).
• What happens if I enable generateSourceMaps on a production build?
  Source‑map files are added to the output, increasing build size but they are not requested by the async snippet unless developer tools are open.

Core use cases for self-hosted SeaText assets

Hosting the SeaText SDK and translation JSON on your own CDN lets you keep assets in a specific region to satisfy GDPR or data‑residency rules. It also cuts latency for users near your edge locations and lets you apply enterprise security controls such as WAF rules, custom headers, or private‑link access. Internal tools can use caching policies that are not offered on a shared SaaS CDN.

Prerequisites

• Access to a CDN service (AWS CloudFront, Cloudflare, Azure CDN, or equivalent).
• A SeaText project from which you can download the SDK JavaScript bundle and the translation JSON files.
• A CI/CD pipeline that can run file‑transfer commands (e.g., AWS CLI, curl, Azure CLI).
• Ability to set HTTP Cache‑Control and CORS headers on the CDN edge.

CDN comparison table

Choose CloudFront if you already run workloads on AWS; choose Cloudflare for the fastest invalidation and lowest cost; choose Azure CDN for deep integration with Microsoft services and strong compliance coverage.

Trade‑offs: self‑hosted CDN vs SeaText managed CDN

Pros of self‑hosted CDN: Full control over geographic placement, ability to enforce custom security policies, alignment with internal data‑governance, and freedom to set any Cache‑Control or CORS rules.

Cons of self‑hosted CDN: Operational overhead for distribution management, responsibility for cache invalidation and syncing, and the need to monitor edge health and billing.

SeaText managed CDN: Zero‑maintenance edge delivery, automatic global propagation, built‑in security basics, but limited to SeaText‑provided regions and less flexibility for custom headers or WAF integration.

Limitations and common pitfalls

Misconfigured CORS headers block the SDK from fetching translation JSON, causing runtime errors. CDN downtime or mis‑routed origin requests can make assets unavailable. Stale cache appears when invalidation is skipped after a translation update, leading to outdated content. Over‑aggressive caching (very long max‑age) delays SDK fixes, while too short a max‑age raises origin load and cost.

CORS configuration guidance

AWS CloudFront

1. Open the distribution’s Origin Response Headers in the CloudFront console.
2. Add a header: Access-Control-Allow-Origin with value * or your SPA domain.
3. Optionally add Access-Control-Allow-Methods: GET,OPTIONS and Access-Control-Allow-Headers: *.
4. Save changes and wait for propagation (usually < 1 minute).

Cloudflare

1. Go to Rules → Transform Rules for your zone.
2. Create a rule that matches */seatext/*.
3. Set Modify Response Header to Access-Control-Allow-Origin with value * or your SPA domain.
4. Deploy the rule; changes take effect instantly.

Azure CDN (Standard Microsoft)

1. Open the CDN endpoint → Rules engine.
2. Add a rule with condition Path ends with /seatext/*.
3. Action: Modify response header → Access-Control-Allow-Origin → * or your SPA domain.
4. Save and enable the rule; propagation is typically under a minute.

Platform‑specific CI/CD pipeline examples

AWS CloudFront with AWS CLI

# Assume SDK and JSON are in ./dist/seatext/
aws s3 sync ./dist/seatext/ s3://my-cdn-bucket/seatext/ --delete
# Invalidate edge cache for changed files
aws cloudfront create-invalidation --distribution-id E1234567890ABC --paths "/seatext/*"

Cloudflare with API cache purge

# Upload via FTP, Rclone, or similar to your origin storage
# Then purge Cloudflare cache
curl -X POST "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/purge_cache" \
     -H "X-Auth-Email: $CF_EMAIL" \
     -H "X-Auth-Key: $CF_API_KEY" \
     -H "Content-Type: application/json" \
     --data '{"files":["https://cdn.example.com/seatext/*"]}'

Azure CDN with Azure CLI endpoint purge

# Copy files to Azure Blob storage (origin)
azcopy copy ./dist/seatext/ "https://myaccount.blob.core.windows.net/seatext/" --recursive
# Purge CDN endpoint
az cdn endpoint purge --resource-group myGroup --profile-name myProfile \
                     --name myEndpoint --content-paths "/seatext/*"

Verification and testing

1. Deploy a staging build that references your CDN URL, e.g. <script async src='https://cdn.example.com/seatext/seatext-sdk.js'></script>.
2. Open the page, open DevTools → Network, and confirm the SDK and translation JSON load from your CDN.
3. Check the Console for any CORS errors; if present, revisit the CORS rules above.
4. Verify that SeaText can write/read its ID in local storage (no security‑policy blocks).
5. Publish a new translation, run the CI/CD sync, and confirm the updated JSON appears after cache purge.

FAQ

• What if my CDN goes down? Implement a fallback in your HTML that loads the SDK from SeaText’s default CDN if the primary request fails (e.g., using onerror to switch URLs).
• How do I test CORS locally? Serve your SPA from localhost and use a tool like curl -I on the CDN asset URL to verify the Access-Control-Allow-Origin header returns your origin or *.
• Can I use separate CDNs for the SDK and translation files? Yes, but you must configure two customCdnUrl‑like values or load the SDK via one script tag and fetch translations via a separate XHR that points to the second CDN.
• Do I need to version file names? Versioning (e.g., seatext-v2.js) is an alternative to cache purging; the asset‑sync CLI can add hashes if you prefer that approach.
• How often should I renew Cache‑Control for the SDK? A max‑age of 1‑2 hours balances quick updates with reduced origin load; adjust based on your release frequency.
• Is local storage usage affected by CDN choice? No; the SDK writes an ID to local storage regardless of where the script is served, provided the page’s origin permits storage access.

SeaText AI uses a Mutation Observer to watch the DOM for new or changed elements. When a lazy‑loaded component mounts, the observer sees the new nodes and runs the translation pipeline on them.

The language that SeaText uses must be configured before the first render; otherwise the initial markup may flash in the default language until the observer processes it.

Why lazy loading matters for translation

Code splitting reduces the initial JavaScript bundle, but it means parts of the UI are not present in the first HTML paint.

If a translation tool only runs once on page load, those later components stay in the source language.

SeaText’s observer‑based approach solves this by reacting to DOM mutations whenever they happen, so translated text appears as soon as the component is inserted.

How SeaText AI observes DOM mutations

The snippet adds a small script with the async attribute.

After it loads, it creates a MutationObserver that watches the document body for added nodes, attribute changes, and text updates.

Each time the observer records a mutation, SeaText checks whether the new nodes contain translatable text and, if so, replaces it with the version in the active language.

Setting the initial language before first render

SeaText reads the language setting from a global variable or from a cookie that you set early in your bootstrap script.

If this variable is missing, the script falls back to the browser’s language or a default you define in the snippet.

To avoid a flash of untranslated content, set the variable (for example, window.seatextLang = 'es';) before you insert the SeaText snippet or before your SPA framework mounts the root component.

Step‑by‑step: adding SeaText to a code‑split SPA

1. Place the SeaText snippet (the async script tag) inside the <body> of your index.html or the equivalent root template.
2. Before the snippet runs, define the language you want, e.g. window.seatextLang = 'fr';.
3. Build and serve your SPA with the usual commands (npm start, npm run serve, ng serve, etc.).
4. Open the page in a browser, open DevTools, and verify that the SeaText script loaded (look for the request in the Network tab).
5. Navigate to a route that triggers a lazy‑loaded component.
6. In the Elements tab, confirm that the newly inserted nodes have been replaced with translated text.
7. If you see untranslated text, check that the language variable was set before the snippet executed and that the observer is not disconnected by another library.

Common pitfalls and limitations

• Setting the language after the snippet has already run will not retroactively translate existing nodes; you must reload the page or call SeaText’s refresh method (if exposed).
• Some UI libraries replace entire sub‑trees instead of appending nodes; the observer still catches the replacement because it detects subtree changes.
• If you manually detach or destroy the MutationObserver (for example, in a cleanup effect), SeaText will stop translating newly added content.
• The script relies on local storage to store an ID; if your CSP blocks local storage, the ID will not persist but translation still works.
• Cross‑origin iframes are not observed by the main page’s observer; you need a separate snippet inside each iframe.

Performance considerations

The SeaText snippet includes the async attribute, which allows the script to load without blocking HTML parsing.

This helps maintain page load performance, especially on slower connections.

The MutationObserver runs only when the DOM changes, so its overhead is proportional to the frequency of updates.

For SPAs with frequent route changes, the observer processes each lazy‑loaded mount, which is typically a small set of nodes.

Debugging tips

Open Chrome DevTools and go to the Network tab to confirm the SeaText script request returns status 200.

Check the Console for any error messages that might indicate the snippet failed to initialize.

Verify that the global language variable (window.seatextLang) is defined before the script tag executes.

In the Elements tab, inspect a newly added lazy‑loaded component; its text should appear in the target language.

If text remains untranslated, ensure the observer is still active by looking for the SeaText object in the window scope.

Advanced configuration

You can define the default language directly in the snippet if you prefer not to rely on a global variable.

The snippet also reads a cookie named seatext_lang if the global variable is absent.

Both mechanisms allow you to change the language at runtime by updating the variable or cookie and then reloading the page.

For environments with strict Content Security Policy, ensure the script source is allowed and that local storage is not blocked if you need persistent visitor identification.

Frequently asked questions

Do I need to call any API after a lazy load?

No. The Mutation Observer works automatically; you only need to set the language before the first render.

What if I use server‑side rendering for the initial route?

SeaText will translate the server‑rendered HTML on the client after hydration, as long as the language variable is present before the script runs.

Can I change the language on the fly?

Yes. Update the global language variable (or cookie) and reload the page; the observer will then translate new mutations to the new language.

Does SeaText work with Vue 3’s <Suspense>?

Yes. The observer sees the fallback content and the resolved component when it is inserted, translating both as they appear.

Is there a size limit on the DOM that the observer can handle?

The observer scales with the number of nodes; for very large pages you can limit observation to specific containers by adjusting the snippet, but the default setup observes the whole body.

When building a Single Page Application (SPA) with SeaText AI, you may encounter API rate‑limit errors that stop the translation step during the build process.

The usual fix is to enable build‑time caching, batch translation requests, fall back to the local translation file, and, if needed, request a higher quota for your CI/CD runner.

Definition and scope

This guide covers handling SeaText AI API rate limits specifically during the static‑build phase of SPA projects (React, Vue, Angular). It does not cover runtime API calls after the app is deployed.

Common mistake: sending one request per string with no cache or batching

The most frequent error is translating each UI string with a separate API call and not storing the results. This quickly exceeds the per‑minute limit, especially when the app contains hundreds or thousands of keys.

To avoid this, always enable the built‑in build‑time cache (the snippet writes translations to local storage after the first successful call) and group multiple keys into a single batch request. If the API supports batching, send up to 100 keys per call; otherwise, implement a simple queue that flushes every few hundred milliseconds.

What changes during a translated SPA build

During a production build, the SeaText AI snippet runs in the build environment (Node.js or a headless browser). It scans the compiled HTML and JavaScript for translatable strings, sends them to the translation API, and writes the results into a JSON file that the runtime snippet later consumes.

Because the build runs in a short window, all translation requests happen in parallel or rapid succession. This burst traffic is what triggers rate limits. The snippet also uses local storage to cache translations, but that cache is ephemeral in a clean CI container unless you persist it.

How to reduce the number of translation requests

1. Enable build‑time caching: configure the snippet to read and write a cache file (e.g., seatext-cache.json) that survives between builds.
2. Batch requests: collect all unique keys and send them in chunks. Generic practice: aim for 50‑100 keys per request to stay under typical limits.
3. Use the local translation file as a fallback: if the API returns a 429, read the previously generated translation file and continue the build without failing.
4. Deduplicate strings: run a pre‑build script that removes identical keys across components.
5. Limit the translation scope: only translate user‑visible text; exclude developer‑only strings, keys used for testing, or content that is already translated in the repository.

Trade‑offs and edge cases

• Caching adds a file‑system dependency; ensure the CI container has write permissions and that the cache is restored between runs.
• Batching reduces request count but increases payload size; very large batches may hit request‑body limits or increase latency.
• Fallback to a local file means new strings added since the last successful build will not be translated until the next API call succeeds.
• If you run multiple parallel CI jobs (e.g., matrix builds), they share the same API key and quota. Serialize the translation step or assign a dedicated key per job.

Where to check build logs and DevTools

Follow the SPA integration steps from the SeaText documentation (source S1):

1. Insert the SeaText AI snippet in your index.html or framework entry point.
2. Run the standard build command (npm run build, ng build, etc.).
3. Open the build log and search for HTTP 429 responses from the SeaText endpoint.
4. In a local development build, open the browser’s Developer Tools (F12), go to the Network tab, and filter for requests to the SeaText API. Look for 429 status codes and examine the response headers for retry‑after information.
5. Check the Console for any warnings about local storage access or cross‑origin issues.

Prevention strategies

• Add a pre‑build step that checks the size of the translation payload and warns if it exceeds 80% of the known limit (generic practice).
• Commit the generated translation file to the repository and skip the API step when the file is up‑to‑date.
• Monitor API usage via the SeaText dashboard and set alerts at 70% of the quota.
• Use environment‑specific keys: a low‑quota key for local development and a higher‑quota key for CI/CD.

When to escalate

If you have implemented caching, batching, and fallback but still see 429 errors after reducing the payload size, open a support ticket with your build logs and request a quota review.

Limitations

These tactics assume you are using the SeaText AI JavaScript snippet in build‑time mode. They do not apply to runtime translation after the SPA is loaded, nor to scenarios where you have disabled the local storage fallback.

Connecting rate‑limit fixes to SeaText’s broader translation features

SeaText’s Translation Agent handles localization into up to 125 languages, adapts copy and buttons for each market, and tracks performance by language. The same API that serves build‑time translation also powers runtime personalization and A/B testing variants. By stabilizing the build‑time translation pipeline, you ensure that the localized assets fed into SeaText’s optimization agents are complete and up‑to‑date.

FAQ

• What does a 429 response mean? It indicates you have exceeded the allowed number of API requests in the current time window.
• Can I cache translations between builds? Yes, the snippet writes results to local storage and you can persist the generated translation file to reuse it.
• Is batching supported by SeaText AI? The API accepts arrays of keys; check the documentation for the maximum batch size.
• What cost is associated with a higher quota? Quota increases are typically tied to your paid plan; contact sales for details.
• Should I disable the snippet during local development? No, keep it enabled but rely on the local cache to avoid unnecessary calls.

SeaText AI works by rewriting page content after the browser loads a small asynchronous script. In a single‑page application the script runs once on the first page view, but Vue navigates between routes without a full reload. If the snippet is not notified of those route changes, translated or personalized content can become stale. The recommended pattern is to wrap the snippet load in a Vue 3 plugin, provide a thin translation helper via provide/inject, and call a refresh routine whenever the router changes the URL.

Why SPA Initialization Matters for SeaText

SeaText rewrites headlines, buttons, and offers based on the visitor's traffic source, keyword, or language. In a traditional multi‑page site each navigation triggers a fresh script execution. In a Vue SPA the script executes only once, so the AI sees the initial route but not subsequent ones. Without a refresh signal the AI cannot re‑evaluate the new DOM, and personalized variants stop updating. Proper initialization ensures the snippet is ready before any component asks for translation, and that every route change informs the AI to re‑scan the page.

How the Async Snippet Loads

The SeaText account dashboard provides a snippet that looks like this:

<script src="https://cdn.seatext.com/seatext.ai.js" async></script>

According to the official documentation (S1), the snippet includes the async attribute so it never blocks page rendering. The script stores a session ID in localStorage and must be allowed to access that storage. Because the script loads asynchronously, window.seatext (or any global the snippet creates) is not available immediately. Code that depends on the snippet must wait for the script's load event or poll for the global object.

Composable vs App‑Level Initialization Trade‑offs

A composable such as useSeaText() can be called inside a component's setup() function. That works, but the composable runs once per component instance unless you guard it with a module‑level flag. An app‑level plugin runs exactly once when the Vue application is created, making it the natural place to inject the snippet, wait for it to load, and provide the translation helper to the entire component tree. The plugin approach also keeps the main.js clean and avoids calling a composable that contains onMounted from outside a component setup context, which Vue warns against.

Step 1: Add the Snippet to the Entry HTML

Place the snippet exactly as provided by SeaText just before the closing </body> tag in your root index.html. For Vite projects this file lives at the project root (/index.html). For Vue CLI projects it is also /public/index.html. Do not add a custom CDN URL; use the snippet from your account dashboard.

<!-- index.html -->
<body>
  <div id="app"></div>
  <!-- SeaText snippet from your dashboard -->
  <script src="https://cdn.seatext.com/seatext.ai.js" async></script>
</body>

// src/plugins/seatext.js
export default {
  install(app, options = {}) {
    const scriptId = 'seatext-script'
    let readyPromise = null

    // Find the script tag that was added in index.html
    const scriptTag = document.getElementById(scriptId) ||
      Array.from(document.scripts).find(s => s.src.includes('seatext.ai.js'))

    if (scriptTag) {
      scriptTag.id = scriptId
      readyPromise = new Promise(resolve => {
        if (scriptTag.readyState === 'loaded' || scriptTag.readyState === 'complete') {
          resolve()
        } else {
          scriptTag.addEventListener('load', resolve, { once: true })
          scriptTag.addEventListener('error', () => resolve(), { once: true })
        }
      })
    } else {
      // Fallback: snippet not in HTML, inject it (not typical)
      const s = document.createElement('script')
      s.id = scriptId
      s.src = 'https://cdn.seatext.com/seatext.ai.js'
      s.async = true
      document.body.appendChild(s)
      readyPromise = new Promise(resolve => {
        s.addEventListener('load', resolve, { once: true })
        s.addEventListener('error', () => resolve(), { once: true })
      })
    }

    // Helper that components can inject
    const translate = (key, opts = {}) => {
      // The official snippet does not document a translate method.
      // This is a recommended pattern: if the global API appears, call it;
      // otherwise return the original key so the UI never breaks.
      if (window.seatext && typeof window.seatext.translate === 'function') {
        return window.seatext.translate(key, opts)
      }
      return key
    }

    // Provide for inject()
    app.provide('seaTextTranslate', translate)
    // Also expose on app.config.globalProperties for Options API
    app.config.globalProperties.$seaText = { translate, ready: readyPromise }
  }
}

// src/main.js
import { createApp } from 'vue'
import App from './App.vue'
import router from './router'
import seaTextPlugin from './plugins/seatext'

const app = createApp(App)
app.use(router)
app.use(seaTextPlugin)
app.mount('#app')

<script setup>
import { inject, onMounted } from 'vue'
const t = inject('seaTextTranslate')

// Optional: wait for snippet ready before translating dynamic content
onMounted(async () => {
  const { ready } = getCurrentInstance().appContext.config.globalProperties.$seaText
  await ready
  // now dynamic translations can be triggered
})
</script>

<template>
  <div>
    <h1>{{ t('Welcome to our store') }}</h1>
    <button>{{ t('Get started') }}</button>
  </div>
</template>

// src/plugins/seatext-router.js
export default {
  install(app, { router }) {
    if (!router) return
    const { $seaText } = app.config.globalProperties
    const tryRefresh = () => {
      if (window.seatext && typeof window.seatext.refresh === 'function') {
        window.seatext.refresh()
      }
    }
    // Initial refresh after first paint
    router.isReady().then(() => {
      $seaText.ready.then(tryRefresh)
    })
    // Refresh on every navigation
    router.afterEach(() => {
      $seaText.ready.then(tryRefresh)
    })
  }
}

// src/main.js (addition)
import seaTextRouterPlugin from './plugins/seatext-router'
app.use(seaTextRouterPlugin, { router })

// plugins/seatext.client.ts
export default defineNuxtPlugin(nuxtApp => {
  // The snippet is already in app.html or injected via useHead
  const script = document.querySelector('script[src*="seatext.ai.js"]')
  const ready = new Promise(resolve => {
    if (!script) return resolve()
    if (script.readyState === 'loaded' || script.readyState === 'complete') resolve()
    else script.addEventListener('load', () => resolve(), { once: true })
  })
  const translate = (key, opts = {}) =>
    window.seatext?.translate?.(key, opts) ?? key
  return { provide: { seaTextTranslate: translate, seaTextReady: ready } }
})

Why verify SeaText after SPA deployment

import { test, expect } from '@playwright/test';

test('SeaText initializes and translates', async ({ page }) => {
  await page.goto('https://your-app.com');
  // wait for snippet script
  await page.waitForSelector('script[src*="seatext"]', { state: 'attached' });
  // wait for data-seatext attributes
  await expect(page.locator('[data-seatext]')).toHaveCountGreaterThan(0);
  // toggle locale
  await page.selectOption('#language-selector', 'es');
  await expect(page.locator('[data-seatext]')).toHaveCountGreaterThan(0);
  // visual regression (requires Percy/Chromatic integration)
  // await percySnapshot(page, 'homepage-es');
  // health endpoint
  const response = await page.request.get('https://api.seatext.com/health');
  expect(response.status()).toBe(200);
  const body = await response.json();
  expect(body.status).toBe('ok');
});

describe('SeaText verification', () => {
  it('loads snippet and translates', () => {
    cy.visit('https://your-app.com');
    cy.get('script[src*="seatext"]').should('exist');
    cy.get('[data-seatext]').should('have.length.greaterThan', 0);
    cy.get('#language-selector').select('es');
    cy.get('[data-seatext]').should('have.length.greaterThan', 0);
    // visual regression via cypress-image-snapshot or Percy
    // cy.percySnapshot('homepage-es');
    cy.request('https://api.seatext.com/health').then((resp) => {
      expect(resp.status).to.eq(200);
      expect(resp.body.status).to.eq('ok');
    });
  });
});

- name: Run SeaText verification
  run: npx playwright test seatext-verification.spec.ts
  env:
    BASE_URL: ${{ secrets.STAGING_URL }}

SeaText AI offers two ways to work in a Single‑Page Application (SPA). The JavaScript snippet runs in the browser for dynamic features. Server‑side steps are needed only for content that must appear in the raw HTML sent to crawlers.

To get SeaText AI running on your single‑page application, install the provided JavaScript snippet, initialize it after your SPA mounts, and set a scope selector that wraps your main content area.

Prerequisites

You need access to your SPA’s HTML entry point (usually index.html) or the main JavaScript/TypeScript file where the framework mounts the app. You also need permission to use local storage and to load external scripts asynchronously.

Step 1: Add the snippet

Copy the SeaText AI snippet (shown below) and paste it inside the tag of your index.html file, or in the equivalent initialization section of your SPA framework.

SEATEXTCODEINTEGRATION

Step 2: Initialize after app mounts

Ensure the snippet runs after your SPA has rendered its root component. In most frameworks you can place the snippet just before the closing tag or call an initialization function from your root component’s lifecycle hook (e.g., useEffect in React, mounted in Vue, ngOnInit in Angular).

Step 3: Define scope selector

Set a CSS selector that tells SeaText which part of the page to translate and optimize. Typically you wrap your main content in an element with the ID seatext-scope and then configure the selector to match that ID.

Step 4: Framework‑specific instructions

React

After adding the snippet, run npm start (or npm run serve) and open DevTools (F12) to confirm the script loads without errors.

Vue

Use npm run serve and check the Console for any loading issues.

Angular

Run ng serve and verify the Network tab shows the SeaText script with status 200.

Step 5: Verify installation

Open your browser’s Developer Tools, go to the Console tab and look for any SeaText‑related logs. In the Network tab, confirm the snippet file was fetched. Finally, visit a page with dynamic content and verify that the text changes according to your configured language or optimization rules.

Why Integrate SeaText with Single-Page Applications

SeaText translates dynamic content as the SPA renders new views. This means users see text in their language without a full page reload. The async attribute in the snippet keeps the initial load fast, which helps SEO rankings. By serving translated content instantly, you improve engagement for global audiences and reduce bounce rates.

Real‑time translation supports up to 125 languages, letting you reach new markets without building separate sites. The script also runs optimization tests that can improve conversion rates by matching copy to visitor intent. These benefits come from the core SeaText platform, which translates pages, headlines, buttons, and offers into many languages while tracking results by language and market.

Trade-offs and Considerations

Adding the snippet introduces an extra network request. Although it loads asynchronously, it still adds to total byte size. Monitor the impact on Largest Contentful Paint if your SPA already loads many scripts.

You must manage the scope selector carefully. If your SPA changes the DOM structure after initialization, SeaText might miss new content unless you re‑initialize or update the selector. Some custom frameworks manipulate the DOM in ways that hide elements from the selector, requiring a manual call to SeaText’s refresh method.

Cross‑origin requests can fail if the snippet is loaded from a different domain without proper CORS headers. Ensure your SPA’s content delivery network allows the SeaText domain, or host the snippet on your own domain to avoid this issue.

Local storage is used to store a visitor identifier. If your SPA blocks local storage for privacy reasons, SeaText will not work. Test the feature in your target browsers and consider a fallback if storage is unavailable.

Limitations

SeaText relies on local storage to store an identifier; if your SPA blocks local storage, the script will not work. Cross‑origin requests may fail if the snippet is loaded from a different domain without proper CORS headers.

Key facts

• Asynchronous loading: The snippet includes the async attribute for the script tag, ensuring that the SeaText AI script loads asynchronously, which helps in maintaining page load performance.
• Local storage usage: The script stores an ID in the local storage. Ensure that your application has the necessary permissions to access and use local storage.
• Cross‑origin considerations: If your SPA interacts with multiple domains, ensure that the SeaText AI script is compatible and does not face cross‑origin issues.
• Supported frameworks: The integration guide covers React, Vue, and Angular, but the snippet works with any SPA that lets you inject a script tag.
• Snippet placeholder: Insert the exact code SEATEXTCODEINTEGRATION where indicated.

Terminology

Snippet – the small JavaScript file provided by SeaText that loads the AI engine.

Scope selector – a CSS selector that limits SeaText’s modifications to a specific part of the page.

Async attribute – an HTML script attribute that tells the browser to load the script without blocking page rendering.

FAQ

• Do I need to rebuild my SPA after adding the snippet? No. The snippet is loaded at runtime; a rebuild is only required if you change your framework’s build commands.
• Can I use SeaText with a server‑side rendered SPA? Yes, as long as the snippet is included in the initial HTML payload.
• What if my SPA uses a custom framework? The same steps apply: add the snippet to the body, initialize after the root component mounts, and set a scope selector.
• Is there a performance impact? The async attribute minimizes impact; the script loads after the initial render.
• How do I update the snippet later? Replace the old code with the new snippet provided in your SeaText dashboard.

Configure the SeaText AI scope immediately after the SPA finishes its initial render but before any user clicks or navigation occurs. In React, place the configuration inside a useEffect that runs once; in Vue or Angular, use the component’s mounted hook. This timing guarantees that the AI model can tag all subsequent dynamic views, so translations are applied consistently.

useEffect(() => {
  SeaText.configureScope();
}, []);

export default {
  mounted() {
    SeaText.configureScope();
  }
};

ngAfterViewInit() {
  SeaText.configureScope();
}

SeaText AI is a marketing optimization platform. It changes headlines, offers, product blocks, and calls-to-action on a page. It uses a JavaScript snippet to do that. In a Single Page Application, the snippet needs a clear target. That target is called the AI scope.

The short answer: SPAs rewrite the DOM without full page loads, so SeaText must know which subtree to observe. A specific scope configuration prevents missed rewrites and keeps the app fast.

What is AI scope in SeaText?

AI scope is the part of the page SeaText watches. It is usually a container with a stable CSS selector. The SeaText documentation includes a section called How to configure / AI scope. In that section, you can define which container the script should observe.

Why does this matter? SeaText rewrites text and tests variants. It needs to react to changes in the right place. If it cannot see the content, it cannot improve it. If it sees too much, it wastes work.

Why SPAs change the rules for SeaText

An SPA loads one HTML page. React, Vue, and Angular are common SPA frameworks. They update content with JavaScript instead of loading new pages.

A normal website reloads the document each time you navigate. The browser fires a full page-load event. SeaText can attach to the document and watch everything. The page is rebuilt, so the old content is gone.

An SPA does not reload the document. JavaScript changes the view in place. The old page-load events do not fire again. SeaText must instead observe the container that changes. That is why the scope must be explicit.

What happens when the scope is missing or wrong

Without a custom scope, SeaText may watch the whole document. That creates two problems.

First, an SPA produces many DOM changes. Menus open, loaders appear, analytics fire, forms update. Those changes are not relevant to marketing copy. Watching them adds work and can slow the app.

Second, SeaText can miss content. Many SPAs render into a root element. Content can also appear in extra containers outside that root. If the scope does not include those containers, SeaText cannot rewrite the headline, offer, or CTA.

How to choose the right scope selector

Open browser DevTools. Inspect the content you want SeaText to optimize. Look for a stable container around the headline, body copy, offer, product blocks, and CTA.

In React, the root is often #root. In Vue, it is often #app. In Angular, it is often app-root. Those are starting points. The best selector may be a smaller container inside the root. Use a selector that stays the same across routes.

Avoid selecting the entire body unless the page is very small. A smaller scope reduces noise and keeps SeaText focused. If your app has multiple content areas, you need multiple selectors. Add them as a list.

Step-by-step installation for SPAs

The SeaText documentation gives a clear installation path. Follow these steps.

1. Identify the entry point. This is normally index.html or the main JavaScript file.
2. Insert the SeaText snippet in the body tag or the equivalent initialization section.
3. Keep the async attribute on the script tag. The snippet already includes it.
4. Open the SeaText configuration area and go to How to configure / AI scope.
5. Enter the selector for the container you identified.
6. Save the configuration.
7. Build and serve the app using npm start, npm run serve, or ng serve.
8. Open DevTools with F12.
9. Check the Console and Network tabs.
10. Move between routes and confirm the scope is still attached.

If the app uses multiple roots, repeat the selector setup for each root. Test each route that changes content.

Additional SPA considerations from the documentation

The SeaText SPA guide lists three extra points.

Async loading: The snippet includes async. Do not remove it. Async loading keeps the script from blocking page rendering.

Local storage: The script stores an ID in local storage. Your application must allow local storage access. If a browser extension or Content Security Policy blocks it, the script may not work as expected.

Cross-origin compatibility: SPAs often interact with multiple domains. Make sure SeaText can work across origins. Check CORS settings and allowed domains if you see errors.

These details may look small. They often cause setup problems after the scope is correct.

Diagnostic sequence for SPA scope problems

Use this sequence when SeaText does not rewrite content.

1. Open the SPA in an incognito window.
2. Navigate to the route with the missing text.
3. Open DevTools and inspect the element that contains the headline.
4. Check whether that element is inside your declared scope.
5. Check the Console for SeaText errors.
6. Check the Network tab for SeaText requests.
7. If no request appears, the script may not be attached.
8. If the element is outside the scope, add a selector for it.
9. Save and test again.
10. Repeat until the route shows the rewritten copy.

This sequence helps you separate scope errors from script loading errors.

When can you skip a custom scope?

A custom scope is not needed for a static page. If the page never replaces DOM nodes after the initial load, the default document-wide scope works.

But most modern marketing sites use client-side routing, lazy-loaded sections, or dynamic content injection. Any of these patterns can create new content after load. If you use one of them, define a scope.

When in doubt, test a route with fresh content. If SeaText cannot find the new text, add a scope.

Frequently asked questions

Why does SeaText AI need a scope?

Because it must know which container to observe in an SPA. Without that knowledge, it misses changes or watches too much.

Which selector should I use?

Use the smallest stable container around your marketing copy. Inspect the page to confirm the selector stays the same across routes.

Does this work for React, Vue, and Angular?

Yes. The SeaText documentation describes the same snippet for all three frameworks.

What if I use portals or multiple root containers?

Add each container to the scope. SeaText can then watch each area.

What should I do if local storage is blocked?

Check your Content Security Policy and extension settings. SeaText needs local storage access to store a visitor ID.

Can I remove the async attribute?

No. The documentation says the snippet includes async to preserve page-load performance.

Why is cross-origin compatibility important?

SPAs often load assets from other domains. The SeaText script must be able to work with those domains without CORS errors.

For dynamic single‑page applications, the scope setting tells SeaText AI which part of the DOM to watch for changes. The recommended approach is to wrap the frequently updating region in a stable element and mark it with data-seatext-scope="true". Then turn on the auto‑retranslate option so the AI translates any nodes that appear after the initial load.

If the SeaText AI scope is not set correctly in a SPA, translations won’t apply to new routes, dynamic content stays untranslated, and you may see console errors.

This happens because the script cannot detect view changes or the snippet is placed outside the app’s initialization.

Symptoms of Misconfiguration

Newly loaded routes show the original language text.

Buttons and labels that change after the initial load remain untranslated.

The browser console may display warnings such as “SeaText AI: scope not found” or “Failed to translate dynamic content.”

Diagnosis Order

1. Open the browser console and look for SeaText AI messages.
2. Verify that the SeaText AI snippet appears in the page source.
3. Confirm the snippet is located inside the SPA entry point (index.html or main JS/TS file).
4. Check for cross‑origin errors that block the script.
5. Navigate to a different route and observe whether translations update.

Likely Causes

• The snippet sits in a component that unmounts before route changes.
• The async script loads after the SPA router has already rendered the first view.
• Local storage access is denied, preventing the script from storing its ID.
• A Content Security Policy treats the script as cross‑origin and blocks it.

Corrective Actions

1. Move the snippet to the body of index.html or the equivalent root file.
2. Ensure the script tag includes the async attribute and is not deferred incorrectly.
3. Grant the SPA permission to use local storage (usually granted by default).
4. If you use a CSP, add the script’s origin (e.g., cdn.seatext.com) to the script‑src directive.
5. Rebuild and serve the SPA, then open DevTools to confirm no SeaText errors.

Build and Verify Checklist

1. Run the standard build command for your framework (npm run build, ng build, etc.).
2. Serve the production build locally or on a staging server.
3. Open Developer Tools (F12) and inspect the Console and Network tabs.
4. Confirm the SeaText AI script is requested and loads with a 200 status.
5. Look for an initialization log such as “SeaText AI initialized.”
6. Navigate between routes and verify that translated text appears on each view.
7. If any error appears, return to the Diagnosis Order steps.

Framework‑Specific Setup Guidance

React

Insert the SeaText AI snippet inside the body tag of public/index.html before the root div.

Run npm start or npm run build then serve the build.

Open DevTools, check the Console for the initialization message, and test a route change.

Vue

Place the snippet in the body of index.html (or the equivalent entry HTML used by Vue CLI/Vite).

Execute npm run serve or npm run build and serve the output.

Verify the script loads asynchronously and that translations update on navigation.

Angular

Add the snippet to src/index.html within the body section, before the <app-root> element.

Run ng serve for development or ng build --prod for production.

Confirm the script appears in the Network tab and that route changes trigger translation.

Note: The official documentation states the same integration steps apply to React, Vue, and Angular; no framework‑specific code changes are required beyond snippet placement.

Scope Troubleshooting Walkthrough

1. Confirm the snippet is present in the built HTML (view page source).
2. Check that the script tag has async and no defer that would delay execution.
3. Open the Console; filter for “SeaText”. Expect an initialization line.
4. If the line is missing, verify network request for the script succeeded.
5. Test a route change; watch for a “detected route change” log (if the script emits one).
6. If translations still do not appear, inspect local storage for a SeaText ID key.
7. If the key is absent, ensure the page is not running in a private/incognito mode that blocks storage.
8. Review CSP headers; add the script origin to script-src if needed.
9. Re‑build, re‑serve, and repeat the verification steps.

How SeaText AI Scope Works in SPA (Diagnostic Hypotheses)

The public documentation does not describe the internal detection mechanism.

Based on typical SPA integration patterns, the script likely uses a mutation observer to watch for new DOM nodes and may listen to the History API for route changes.

Treat these as hypotheses; if the script behaves differently, adjust troubleshooting accordingly.

Key Facts

Best Practices for Configuration

• Place the snippet before any framework‑specific mount call.
• Validate the snippet appears in the page source after build.
• After each build, open the console and look for SeaText AI initialization messages.
• When using a micro‑frontend architecture, include the snippet in each entry point that needs translation.

Limitations and When Advice Does Not Apply

If you use a server‑side rendered shell that hydrates the SPA after the initial HTML, the snippet must be present in the shell HTML, not only in the client bundle.

The advice does not apply to pure multi‑page applications where each page is a full reload; there, scope is not needed.

Terminology

Scope – the part of the application that SeaText AI monitors for changes to translate.

Entry point – the HTML file or JavaScript module where the SPA framework mounts the root component.

Mutation observer – a browser API that can detect newly added DOM nodes (hypothesized usage).

FAQ

Why does my translation work on the first page but not after navigation?

The snippet is likely inside a component that gets destroyed on navigation, so the observer is lost. Move it to the root HTML.

How can I verify that SeaText AI is observing route changes?

Open DevTools, go to the Console, and filter for SeaText. You should see a log like “SeaText AI initialized” and then a route‑change detection log when you navigate (if the script emits one).

What if my CSP blocks the script?

Add the script’s host (usually cdn.seatext.com) to the script‑src directive, or host the snippet on your own domain.

Do I need to set scope manually for frameworks like React?

No, if the snippet is in the entry point and loads async, SeaText AI automatically detects React’s virtual DOM updates (as described in the generic integration guide).

Symptoms you might notice

Incorrect
<!-- Inside a React component that unmounts on route change -->
function App() {
  useEffect(() => {
    const script = document.createElement('script');
    script.src = 'https://cdn.seatext.com/ai.js';
    script.async = true;
    document.body.appendChild(script);
  }, []);
  return <div id="root"></div>;
}

Correct
<!-- In index.html, before the closing </body> tag -->
<script async src="https://cdn.seatext.com/ai.js" data-scope="#root"></script>

Incorrect
// No re‑initialisation after React Router navigation
import { BrowserRouter, Routes, Route } from 'react-router-dom';
function App() {
  return (
    <BrowserRouter>
      <Routes>
        <Route path="/" element=<Home /> />
        <Route path="/about" element=<About /> />
      </Routes>
    </BrowserRouter>
  );
}

Correct
// Re‑initialise SeaText on every route change
import { useEffect } from 'react';
import { useLocation } from 'react-router-dom';
function SeaTextReinit() {
  const location = useLocation();
  useEffect(() => {
    if (window.SeatextAI) {
      window.SeatextAI.reinit();
    }
  }, [location]);
  return null;
}
function App() {
  return (
    <BrowserRouter>
      <SeaTextReinit />
      <Routes>
        <Route path="/" element=<Home /> />
        <Route path="/about" element=<About /> />
      </Routes>
    </BrowserRouter>
  );
}

Incorrect
<script async src="https://cdn.seatext.com/ai.js" data-scope="body"></script>

Correct
<script async src="https://cdn.seatext.com/ai.js" data-scope="#root"></script>
<!-- Or a dedicated attribute -->
<script async src="https://cdn.seatext.com/ai.js" data-scope="[data-seatext-scope]"></script>

Incorrect
<script src="https://cdn.seatext.com/ai.js" data-scope="#root"></script>

Correct
<script async src="https://cdn.seatext.com/ai.js" data-scope="#root"></script>

Incorrect
<!-- CSP that blocks localStorage -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self';">

Correct
<!-- CSP allowing localStorage and the SeaText domain -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' https://cdn.seatext.com; connect-src 'self' https://cdn.seatext.com;">

To verify that SeaText AI scope is working in your SPA, open the app in a browser, navigate through every route, trigger any asynchronous content, and inspect the DOM for the data-seatext-translated attribute that SeaText adds to each translated element.

If you see the attribute on static text, buttons, links, form labels, and dynamically loaded components, the snippet is active and the AI scope is covering those elements. If the attribute is missing, the AI is not processing the nodes you expect.

Why scope verification matters

Scope verification is not a nice-to-have. It is the main control that determines which DOM nodes SeaText will process. In a single page application, a small scope error can affect every route.

When the scope is too narrow, key components stay untranslated. A visitor may see a translated hero section but an untranslated checkout button. That breaks trust. It also stops the buyer from completing the action the page was built for.

When the scope is too broad, the AI sends more nodes to the translation service than needed. This can waste budget on duplicate text, hidden templates, and non-visible content. It can also slow down interaction because the MutationObserver is watching many nodes and queuing extra work.

In an SPA, routes are often loaded with dynamic imports. Code splitting means one page may have dozens of independently mounted components. If the scope only covers the initial mount, every lazy-loaded component will be missed. The result is a mixed-language interface that looks broken. That is why you must verify scope after route changes, not just on the first load.

From the official docs, the SeaText snippet loads asynchronously and stores an ID in local storage. The app must allow local storage access. The scope decides what the AI examines for translation, headline rewriting, and CTA adaptation. A proper check confirms that the scope matches the actual DOM state.

Prerequisites

Before you start, make sure the SeaText AI snippet is installed according to the SPA integration guide. The official guide says to identify the entry point, then insert the snippet within the body tag of your index.html file, or in the equivalent initialization section of your SPA framework.

Use a development or staging environment. You need to open DevTools, so production traffic should not be affected. Run the app locally with a framework command such as npm start, npm run serve, or ng serve.

Confirm that the script loads correctly. In DevTools, open the Network tab and look for the SeaText script. It should return status 200. If it is blocked by a content security policy, the script will not appear, and the translation attribute will never be added.

Also confirm that the application allows local storage. The SeaText snippet stores an ID in local storage. If local storage is disabled or blocked, the snippet may not work as expected.

Step-by-step validation checklist

Use this checklist every time you change routing, add lazy-loaded features, or alter the AI scope. It is a practical diagnostic sequence for any SPA framework.

1. Load your SPA in Chrome or Firefox and open Developer Tools with F12.
2. Go to the Console tab and run document.querySelectorAll('[data-seatext-translated]'). This shows whether any elements already have the attribute.
3. Navigate to each top-level route, such as /home, /products, and /about. After each route change, repeat the console query.
4. Trigger asynchronous content. Load lazy modules, scroll an infinite feed, or wait for data fetched from an API. Let the content render, then run the query again.
5. Check that the number of matched elements grows as new content appears. The attribute should be present on visible text, buttons, links, form labels, and other user-facing elements.
6. If available, enable the SeaText AI debug flag. This logs translation events in the Console and makes it easier to spot skipped nodes.

For more consistency, write the query as a one-liner that returns the count: document.querySelectorAll('[data-seatext-translated]').length. Use that count as a rough signal. If it stays at zero on a route, the scope is not covering that route.

What to look for in DevTools

In the Elements panel, select any piece of UI text and look at its attributes. A translated element will show data-seatext-translated='true' or a similar value. The attribute is added after the AI finishes processing the node, so it may appear a few milliseconds after the node is inserted.

In the Console, the query returns a NodeList. You can expand it to see every matched element. This is useful when you want to confirm that a specific component is covered. Search for the component name in the list or right-click an element to reveal it in the Elements panel.

You can also test a specific container. For example, to check a product card, run document.querySelector('.product-card').querySelectorAll('[data-seatext-translated]'). If the container returns zero matched nodes, the AI scope is not reaching that component.

Keep the Console open while you navigate. If the snippet logs errors, read them carefully. A Content Security Policy error, a failed fetch, or a blocked local storage write all point to configuration problems outside SeaText.

How SeaText AI scope works in SPAs

SeaText AI scope defines the set of DOM nodes that the AI examines for translation, headline rewriting, or CTA adaptation. The snippet watches the DOM for nodes that match the configured selectors. By default, the scope is designed to cover visible text that users can see and read.

Under the hood, the snippet uses a MutationObserver. This browser API watches for changes in the DOM tree. When a mutation occurs, the observer compares the added nodes against the scope rules. If a node matches, the snippet sends it to the translation service. When the service returns, the snippet injects the translated text and adds the data-seatext-translated attribute.

This is why route changes work without a full page reload. In a modern SPA, the router swaps components in and out of the DOM. Each swap creates new nodes. The MutationObserver sees those nodes and checks them against the scope. The same process runs when a dynamic import loads a new component, when an infinite scroll adds a new card, or when a modal opens for the first time.

There is a trade-off. Observing many nodes can cost performance. The callback runs after every mutation, so a page that creates hundreds of nodes at once may cause a burst of work. The SeaText snippet uses asynchronous loading to protect page load performance, but the observer still has to inspect each change. Keeping the scope as tight as possible reduces the number of nodes that have to be checked and translated.

Deeply nested SPA trees can make scope verification harder. The observer sees the parent node before the child nodes are fully rendered. If your framework renders content in stages, the observer will process each stage separately. Wait for the render to settle before you query the DOM.

Common pitfalls and how to avoid them

Many scope failures look like translation failures. In fact, the root cause is usually a timing issue, a selector mismatch, or a browser policy.

• Missing attribute on dynamically loaded content. Wait for the network request to finish before querying. If you query too early, the node exists but the AI has not processed it yet.
• Script blocked by a content security policy. Verify that the script loads in the Network tab with status 200. If the policy blocks remote scripts, no translation will happen.
• False positives from other libraries. Some tools add similar attributes. The SeaText attribute always starts with data-seatext-, so check the full attribute name before drawing a conclusion.
• Hidden or off-screen content. The scope may skip elements that are not visible. If a component is hidden with CSS display:none, the observer may not process it. This is usually correct behavior, not a bug.
• Shadow DOM. SeaText may not pierce shadow roots by default. If your components use shadow DOM, test those components separately. For details, check with the vendor.

If you see the attribute on some routes but not others, focus on the routes that fail. Look at the rendered HTML and compare it with the selectors defined in your scope. A component may be using a different class name, a different tag, or a different rendering mode than you expected.

Limitations and when this advice does not apply

This checklist assumes you are using the default SeaText AI scope that translates visible text. If your scope has been customized, you must adjust the queries and expectations accordingly.

The method shows that the AI has attempted to process a node. It does not prove that the translation is correct. A translated string may be wrong, truncated, or contextually off. You still need a human review or a separate quality check if the language output matters for your conversions.

The attribute also says nothing about A/B testing variants. SeaText can create variants and test them. The attribute marks translated nodes, but it does not tell you which variant the visitor received. Use the SeaText dashboard for that data.

If the SeaText snippet is not installed in the entry point, this checklist will not help. Revisit the SPA integration guide first. The article also assumes you are testing a client-side rendered SPA. If your app uses server-side rendering or static generation, the insertion points and mutation behavior may differ.

For unsupported details such as framework-specific selectors, custom fields, or edge cases in your component library, check with the vendor. The official documentation is the best source for the current snippet behavior.

FAQ

Do I need to reload the page after each route change? No. Modern SPA routers update the DOM without a full reload. Wait for the route-change event to finish before querying.

What if I see the attribute on some elements but not others? Check whether the missing elements are hidden with CSS display:none or are inside a shadow DOM. SeaText AI may not process hidden elements or shadow roots by default.

Can I automate this test in CI? Yes. Use a headless browser such as Puppeteer or Playwright to navigate routes, wait for network idle, then evaluate document.querySelectorAll('[data-seatext-translated]').length and assert it is greater than zero.

Does the attribute remain after hot-module replacement? Yes, as long as the node stays in the DOM. Newly added nodes receive the attribute after the AI processes them.

Why should I verify scope on every route? Because an SPA does not load every component up front. Each route may mount different components. A scope that works on the home route can still miss the checkout route.

Yes, you can configure multiple scopes for different routes in your single-page application (SPA) with SeaText. To do this, you will need to reinitialize the SeaText snippet with a new scope each time your SPA route changes. That said, a single stable scope used across all routes is simpler to implement and maintain for most teams.

Single Scope vs. Multiple Scopes: Core Tradeoffs

Choosing between a single stable scope and per-route scopes comes down to your SPA’s content structure and maintenance priorities. The table below breaks down the key differences to help you decide:

How SeaText Scopes Work in SPAs

A scope in SeaText defines the set of personalization rules, content swaps, and tracking context applied to your site. For SPAs, the SeaText snippet loads asynchronously by default to avoid blocking your app’s initial render, and stores a session ID in local storage to maintain context across route changes.

When you use a single stable scope, that same context and set of rules apply to every route the user visits within your SPA. For per-route scopes, you create separate context boundaries for each section of your SPA, so each route can have its own unique personalization and content rules.

When to Use a Single Stable Scope

A single stable scope is the right choice for most SPA use cases. If your routes all serve the same core audience and share consistent content goals—like a SaaS app with aligned onboarding flows, or a marketing site with unified messaging across pages—a single scope eliminates unnecessary overhead.

This setup works with SeaText’s default SPA integration out of the box. You only need to add the base snippet to your SPA’s entry point (index.html or main framework initialization file) with no extra route-specific configuration. The async loading and local storage-based session tracking work automatically to maintain context as users navigate between routes.

When to Use Per-Route Scopes

Per-route scopes are only necessary for edge cases where separate sections of your SPA require completely distinct personalization rules. Common examples include a public marketing section paired with a private user dashboard that uses different content sets, or separate regional storefronts with unique product catalogs and offers.

To implement per-route scopes, you will need to add event listeners to your SPA’s router (React Router, Vue Router, Angular Router, etc.) that trigger a SeaText scope reset every time the route changes. This involves reinitializing the SeaText snippet with a new scope for the target route. The exact reinitialization method is not documented in the public SeaText SPA guide; you should verify the correct pattern against the official SeaText documentation or contact support before deployment.

Step-by-Step Setup for Both Approaches

Single Scope Setup

1. Insert the SeaText AI snippet into your SPA’s entry point, either in the body tag of your index.html file or the equivalent initialization section of your framework.
2. Build and serve your SPA using your framework’s standard commands (npm start, npm run serve, ng serve, etc.).
3. Open your browser’s Developer Tools (F12) and check the Console and Network tabs to confirm the SeaText snippet loads correctly with no errors.

Per-Route Scope Setup

1. Add the base SeaText snippet to your SPA’s entry point as outlined above.
2. Add a route change listener to your SPA’s router that triggers a reinitialization of the SeaText snippet when navigation occurs.
3. Inside the route change handler, reinitialize SeaText with the new scope assigned to the target route. Because SeaText does not publish a public destroy/reinitialize API, treat this as a framework-level integration pattern that must be validated against the official SeaText docs or confirmed with SeaText support.
4. Test navigation between all routes to confirm scopes apply correctly, with no flickering, broken personalization, or lost user context.

What Happens to Session Context When a Route Scope Is Reset

SeaText stores a session ID in local storage to maintain user context across page views. When you reinitialize the snippet with a new scope, the existing session ID remains in local storage unless your reinitialization logic explicitly clears it. If the session ID persists, SeaText may continue to associate the user with the previous scope’s personalization history, which can cause content from the old scope to leak into the new route. To avoid this, you should either clear the relevant local storage keys before reinitializing or ensure the new scope’s configuration overrides any stale context. Test thoroughly in a staging environment to confirm that user context resets as expected.

Migration Note: Moving from Single Scope to Per-Route Scopes

If you start with a single scope and later decide you need per-route scopes, plan the migration carefully. First, audit all routes and define the distinct scope each requires. Then, implement a router middleware that maps each route to its scope identifier. Deploy the new logic behind a feature flag so you can roll back if issues arise. Monitor personalization accuracy and console errors for at least one full release cycle before removing the flag. Keep the single-scope snippet as a fallback for any routes that have not yet been migrated.

Decision Summary: How to Choose

Use a single stable scope if your SPA has fewer than five major sections, shares a common audience, and your team prefers minimal configuration. Switch to per-route scopes only when you have clear evidence that different routes need mutually exclusive personalization rules—such as separate product lines, distinct geographic markets, or a public/private split. Start simple; you can always add per-route scopes later without rewriting the entire integration.

Key Limitations to Check

Before implementing either scope setup, confirm the following to avoid broken functionality:

• Cross-origin compatibility: If your SPA interacts with multiple domains, ensure SeaText’s script is compatible with all origins to avoid scope context loss.
• Local storage permissions: Confirm your SPA has permission to access local storage, as SeaText uses it to store session IDs for scope tracking.
• Async loading behavior: Per-route reinitialization may cause a brief delay in personalization applying on route change if not optimized, due to the async nature of the SeaText snippet.

Per-route scopes also add ongoing development overhead, so only use this setup if your use case truly requires separate context per route.

Frequently Asked Questions

Will per-route scopes slow down my SPA?

Potentially, if your reinitialization logic is not optimized. Each reinitialize call loads SeaText’s script resources again, which can add minor load time on route changes. A single scope avoids this overhead entirely.

Can I mix single and per-route scopes?

Yes, you can use a single global scope for most routes and only apply per-route scopes to specific sections that need unique context. Just ensure your route change logic only triggers reinitialization for the routes that require a new scope.

What happens if I forget to reinitialize the scope before navigating?

You may end up with overlapping scope contexts, which can cause conflicting personalization rules, broken content swaps, or incorrect data tracking. Always ensure the reinitialization logic runs before the new route renders.

Do per-route scopes work with server-side rendered SPAs?

Yes, but you’ll need to ensure the scope is initialized correctly on both the server and client side to avoid hydration mismatches. Check SeaText’s SSR documentation for specific guidance.

Can I test scope configurations before deploying?

Yes, use your SPA’s local development environment to test route changes and confirm scopes apply as expected. You can also use SeaText’s preview tools to validate content swaps for each scope before pushing to production.