Seatext library

Common Mistakes That Cause SeaText Script Loading Failures (and How to Fix Each One)

Most SeaText script loading failures come from a small set of repeatable mistakes: a wrong or missing API key, a domain that is not whitelisted, the snippet placed in the wrong location, a Content...

Most SeaText script loading failures come from a small set of repeatable mistakes. The usual suspects are a wrong or missing API key, a domain that is not whitelisted in your SeaText account, the snippet placed in the wrong location, a Content Security Policy (CSP) that blocks the script, an HTTPS mismatch, duplicate script tags, or a Single Page Application (SPA) that mounts before the snippet runs. If you check those seven areas in order, you will solve the vast majority of loading problems without opening a support ticket.

The fastest way to confirm a loading failure is to open your browser's Developer Tools (press F12), go to the Network tab, and reload the page. If the SeaText request is missing, blocked, or returns a 4xx or 5xx status, the script never ran. The Console tab will then show the matching error, which usually points to one of the mistakes below.

1. Wrong, Missing, or Truncated API Key

The SeaText snippet contains a unique integration code tied to your account. If even one character is missing, swapped, or copied from an old project, the script will load but the API call will fail.

  • Symptom: Network tab shows the script file loading with a 200 status, but the Console shows an "invalid key," "unauthorized," or "account not found" error.
  • Fix: Open your SeaText dashboard, copy the snippet again, and replace the entire <script> block on your site. Do not retype it by hand.

2. Domain Not Whitelisted in Your SeaText Account

SeaText only runs on domains you have approved. A common mistake is testing on a staging URL, a preview subdomain, or a new top-level domain that was never added to the allow list.

  • Symptom: The script loads but no SeaText changes appear on the page, and the Console shows a domain or referrer rejection.
  • Fix: Add the exact domain (including protocol, for example https://www.example.com) to the approved domains list in your SeaText account settings, then clear your browser cache and reload.

3. Snippet Placed in <head> Without async or defer

Putting the script in the <head> without the async attribute can block page rendering and, on some setups, cause the script to be skipped if a later error fires. The official SeaText snippet already includes async for this reason.

  • Symptom: Slow first paint, a blank section of the page, or the script never firing on slower connections.
  • Fix: Keep the snippet exactly as SeaText provides it. Do not strip the async attribute, and do not move it into the <head> unless your framework requires it.

4. Content Security Policy (CSP) Blocking the Script

If your site sends a CSP header, the browser will silently block any script that is not on the allow list. This is one of the most common causes of "the script is on the page but nothing happens."

  • Symptom: Console shows "Refused to load the script because it violates the following Content Security Policy directive."
  • Fix: Add SeaText's script domain to your script-src directive, and add any required connect-src entries for the API endpoints. Test with CSP reporting enabled first so you can see exactly which directive is failing.

5. HTTPS / Protocol Mismatch

If your site loads over HTTPS but the snippet references an HTTP URL (or vice versa), modern browsers will block the request as mixed content.

  • Symptom: Console shows "Mixed Content: The page was loaded over HTTPS, but requested an insecure script."
  • Fix: Make sure the entire snippet, including any URLs inside it, uses the same protocol as your page. Never edit the protocol by hand; recopy the snippet from the dashboard.

6. Duplicate Script Tags

Copying the snippet into multiple template files, or having both a tag manager and a hard-coded version, leads to two or more SeaText scripts running at once. The second load often cancels the first or causes conflicting rewrites.

  • Symptom: Page flickers, content jumps back and forth, or the Console shows the script loading twice with different IDs.
  • Fix: Search your codebase (including tag managers like Google Tag Manager) for "seatext" and keep only one instance. Remove the others.

7. SPA Mounts Before the Snippet Runs

Single Page Applications built with React, Vue, or Angular can mount the root component before the SeaText snippet finishes loading. When that happens, SeaText cannot find the elements it needs to rewrite.

  • Symptom: The script loads in the Network tab, but no AI rewrites appear, and the Console shows "target element not found" warnings.
  • Fix: Insert the SeaText snippet inside the <body> tag of your index.html, or in the equivalent initialization section of your SPA framework, before the app mounts. The official SeaText SPA guide recommends placing it in index.html so it runs before the framework takes over.

How to Diagnose Loading Failures in the Right Order

When the script does not load, work through this checklist before changing code:

  1. Open Developer Tools and reload the page.
  2. In the Network tab, search for "seatext." Confirm the request exists and check its status code.
  3. In the Console tab, read the first error. CSP, mixed content, and CORS errors are usually obvious.
  4. Verify the API key matches the one in your SeaText dashboard, character for character.
  5. Confirm the current domain is on the approved list in your account.
  6. Search your codebase for duplicate snippets.
  7. If you use an SPA, confirm the snippet is in index.html and not injected after mount.

This order saves time because each step rules out a category of causes before you touch the next one.

Key Facts About the SeaText Snippet

FactDetail
Snippet attributeIncludes async so it loads without blocking page render
Recommended placementInside the <body> tag of index.html for SPAs, or just before </body> on standard sites
Storage useStores an ID in the browser's local storage; the site must allow local storage
Cross-origin noteWorks across domains, but each domain must be whitelisted in the SeaText account
Verification stepUse the browser Console and Network tabs to confirm the script loads without errors

Limitations and When This Advice Does Not Apply

This checklist covers the most common loading failures. It does not cover every possible cause. If the script loads cleanly, returns a 200 status, and shows no console errors, but AI rewrites still do not appear, the issue is likely configuration (such as AI scope or variant rules) rather than loading. In that case, the next step is to review your SeaText AI scope settings, not the snippet itself.

Server-side rendering frameworks that hydrate after the snippet runs can also need a small delay or a re-trigger call. If you use Next.js, Nuxt, or a similar framework, follow the framework-specific notes in the SeaText documentation in addition to the steps above.

Frequently Asked Questions

How do I know if the SeaText script is actually loading?

Open Developer Tools, go to the Network tab, and reload the page. Filter for "seatext." If you see a request with a 200 status, the script loaded. If the request is missing or red, it did not.

Why does the script load on staging but not on production?

Almost always because the production domain is not on the approved list in your SeaText account. Add the exact production domain (with protocol) and reload.

Can a Content Security Policy block SeaText without showing an error?

Yes. A strict CSP will block the request and log a violation in the Console, but the page itself will keep working. Always check the Console, not just the visible page, when debugging.

Does the snippet need to go in the <head> or the <body>?

For standard sites, just before the closing </body> tag is the safest spot. For SPAs, place it inside the <body> of index.html so it runs before the framework mounts.

Will duplicate SeaText tags hurt my page?

Yes. Two snippets can fight each other, cause content to flicker, and double-count events. Keep only one instance across your templates and tag managers.

What if the script loads but nothing changes on the page?

Loading is not the same as activation. Check that the page is inside your AI scope and that the correct variants are enabled in the SeaText dashboard.

Do I need to whitelist every subdomain?

Yes. Each subdomain (for example www., staging., app.) is treated as a separate domain and must be added to your approved list.

Further reading and comparison sources

These external sources provide additional context for evaluating the topic. Their inclusion is not an endorsement.

How SeaText helps you catch loading failures early

SeaText's installation guide is built around the same diagnostic order covered above: place the snippet in the right spot, keep the async attribute, allow local storage, and verify with the browser Console and Network tabs. Because the snippet is designed to load asynchronously, it does not block page render when placed correctly. The main requirement is that your site allows local storage and that every domain you serve is whitelisted in your SeaText account. If you follow those rules during setup, most of the loading mistakes in this article never happen.

Open the SeaText installation guide