ModHeader V1

Modify request and response headers

Modify HTTP request and response headers. Override Origin, cookies, and CORS for local API testing. FEATURES • Modify request and response headers • Override Origin (e.g. spoof a production origin from localhost) • Multiple profiles — switch, pause, or enable rules quickly • URL filters so rules only apply to selected APIs/hosts • Cookie and redirect overrides • Import / export profiles • Lock modifications to the current tab • Works in Incognito (spanning) COMMON USE CASES • Call APIs from localhost when the server rejects origin_not_allowed • Fix or simulate CORS by setting Access-Control-Allow-Origin • Inject Authorization tokens for API testing • Change User-Agent, Referer, Content-Type, and custom headers • Reproduce production header behavior in a local environment PERMISSIONS This extension needs access to network requests and storage so it can apply your header rules and save your profiles locally. Built for developers who need fast, repeatable header control without changing application code.