External websites

Test Chain isn't an SDK you import or a package you add to a build. It's a transparent HTTP proxy that sits in front of a web app, so it can record and replay flows on sites you don't control and can't modify.

What the proxy does on the way through

When you point a session at a URL, every request flows through the proxy before it reaches the iframe:

• Strips frame-busting headers — X-Frame-Options and Content-Security-Policy are removed so the page renders inside the recorder.
• Rewrites URLs — relative and absolute links are rewritten to proxy URLs, using the final post-redirect URL as the base so relative paths never break.
• Injects the recorder transparently into every HTML response.
• Follows redirects manually, capturing Set-Cookie at every hop — so auth cookies set during a redirect still reach the session jar.
• Forwards your headers — everything except a small proxy-internal blocklist, so custom Authorization or device headers aren't silently dropped.

Where this earns its keep

• Testing a staging deployment without wiring test hooks into the app.
• Driving a vendor or partner portal you have a login for but no source access to.
• Recording a third-party checkout — Stripe and PayPal redirects get rewritten to a safe stub page so the run never leaves the flow.

Because the app loads exactly as a real browser sees it, what you record is what runs — no instrumented build, no divergence between the test environment and production.