What is the difference between edge server redirects and JavaScript DOM replacement for website testing?

Edge server redirects swap a visitor to a test variant before the page loads, which prevents flicker and layout shift. JavaScript DOM replacement changes content after the page loads in the browser, which can be slower and easier for ad blockers or browser privacy rules to interfere with. Seatext uses this edge-based approach in its split URL testing agent to avoid revenue leaks and keep tracking signals intact.