Configurable Header Manager von Marlon Wiss

Configurable Header Manager lets you intercept and modify HTTP headers on any
website — without installing anything beyond the extension itself.

HOW IT WORKS
Create rules that match a URL pattern (with wildcard support) and define what
happens to a header: set a value, remove it entirely, or append to it. Rules
apply to request headers (sent to the server) or response headers (received
from the server). Toggle individual rules on and off without deleting them.

FEATURES
• Add, edit and delete header rules per URL pattern
• Match any domain or path with wildcard patterns (e.g. ://.example.com/*)
• Set, remove or append header values
• Works on both request and response headers
• Enable or disable rules individually — no need to delete and recreate
• Import and export your full rule set as plain JSON — easy backup or team sharing
• Load a rule configuration directly from a URL
• Instant apply — no page reload of the extension required

SIMPLE BY DESIGN
The UI is intentionally minimal: a list of your rules, a small form to add or
edit one, and an import/export panel. Nothing hidden, nothing complex.

SECURE & PRIVACY-FIRST
• Zero external dependencies — no npm packages, no remote scripts, no CDN calls
• All rules are stored locally in your browser (browser.storage.local)
• No analytics, no telemetry, no network requests made by the extension itself
• Fully open source — you can read every line of code before installing
• Uses the Declarative Net Request API, so the extension never sees the actual
request content — the browser engine applies rules directly
• data_collection_permissions: none — declared explicitly in the manifest

WHO IS THIS FOR
Developers testing APIs with custom auth headers, CORS overrides or feature
flags; QA engineers spoofing user agents or cache headers; security researchers
inspecting header behaviour — anyone who needs precise, per-URL header control
without a full proxy setup.