Choose the scope
Header capture and attachment apply only to enabled profiles and configured target origins.
A controlled request flow.
Configure a target origin, choose the headers involved, and inspect the resulting session without changing your application code.
Capture a value
Selected response header values are kept in the extension's local session state.
Relay the header
Fixed and captured headers are attached to later matching requests. Excluded paths remain untouched.
Local by design.
The extension is intended for local, staging, internal, and test environments. Its data handling stays narrow and inspectable.
Extension data stays local
Profiles, session state, and audit logs are not sent to the developer or an unrelated data service. Configured header values are attached only to matching target origins.
Clear retention limits
Diagnostic audit logs keep up to 1,000 recent entries for no more than 7 days, and can be cleared at any time.
No persistent URL logging
Request URLs are never written to persistent audit logs. The current browser session keeps only the origin and pathname for recent-log display.
User-controlled scope
Disable a profile, remove target origins, clear captured values, or uninstall the extension to stop its behavior.
HTTP localhost access is included for the default local-development workflow. Every other host is requested only when you add its Target Origin. Capture and attachment remain limited to enabled profiles and configured origins.
Header Relay questions, answered.
The essentials for evaluating how Header Relay fits an API development workflow.
What does Header Relay do?
Header Relay captures response headers you select and adds fixed or captured header values to later browser requests that match your enabled profile.
Which requests can Header Relay modify?
Only requests matching an enabled profile's configured target origins are eligible. Excluded paths remain untouched.
Does Header Relay send data to an external server?
The extension does not send data to the developer, analytics providers, or unrelated servers. Configured header values are attached only to matching target origins; profiles, session state, and audit logs remain in the local Chrome profile. Separately, this documentation site uses GA4 only after you consent.
Where should I use Header Relay?
Header Relay is designed for API development and testing in local, staging, internal, and other controlled environments.