HeaderForge

HTTP header editor for Chromium

Shape every request. Inspect every assumption.

Add, replace, append, or remove HTTP request and response headers with URL-targeted rules. HeaderForge stays local, requires no account, and applies changes through Chrome’s Manifest V3 network API.

Install HeaderForge Read the usage guide

Chrome Web Store link will be added when the extension is published.

Built for focused testing

Useful controls, without the account layer

HeaderForge keeps the workflow close to the network request: define a rule, target a URL, and turn it on.

01 / REQUEST

Rewrite outgoing headers

Set authorization values, feature flags, cookies, user agents, cache directives, and custom headers.

02 / RESPONSE

Test received headers

Change eligible response headers to investigate MIME types, caching, and application-visible metadata.

03 / TARGET

Scope every rule

Use Chrome DNR URL filters to match a host, route, protocol, local server, or all permitted requests.

04 / CONTROL

Pause without deleting

Toggle one rule or pause the complete ruleset. The toolbar badge reports how many rules are active.

05 / PORTABLE

Move rules as JSON

Export a ruleset to the clipboard and import it into another browser profile without internal ID conflicts.

06 / PRIVATE

Keep rules in the browser

Rules live in chrome.storage.local. HeaderForge has no account, analytics, or remote rules service.

Rule anatomy

A readable format for repeatable tests

[
  {
    "enabled": true,
    "target": "request",
    "operation": "set",
    "name": "x-test-user",
    "value": "demo-user",
    "urlFilter": "||api.example.com/"
  }
]

Getting started

From install to first rule

  1. Install and pin HeaderForgeThe Web Store link will appear here after publication. Chromium browsers can also load an unpacked build during development.
  2. Choose request or responseSelect Set, Append, or Remove, then enter the header name and value.
  3. Target the smallest useful scopeA filter such as ||api.example.com/ avoids applying test headers to unrelated traffic.
  4. Enable and verifyChanges apply immediately. Account for caches, redirects, service workers, and browser-protected headers while testing.

Your header values stay local.

See exactly what HeaderForge stores and why each browser permission is needed.

Read the privacy policy