A focused toolkit for Chrome

Request headers.
Exactly where they belong.

Test APIs with exact-host rules, environment profiles, and automatic expiry. All from one small Chrome extension.

Add to Chrome Read the quick start

Free · Chrome 120+ · No account needed

Inside HeaderKit / Explore the product
HeaderKit Rule Manager showing profiles, expiry controls, and request headers grouped by HTTPS host
Every environment in one workspace.
REAL INTERFACE · EXAMPLE DATA
Local settings Exact-host access No telemetry
Small tool. Precise controls.

Less setup.
More useful testing.

01

Switch the environment, keep the context.

Store staging, QA, and development rules in separate profiles. Keep one profile active and see its rules grouped by exact host.

02

Choose the requests that change.

Apply rules to an approved HTTPS host. Narrow them with a path prefix or fetch/XHR matching.

03

Give temporary tests an end time.

Choose one hour, eight hours, or Chrome shutdown. Pause rules at any time without deleting the setup.

HeaderKit current-host popup with enabled and paused staging rules
THE CURRENT-HOST POPUP CHROME EXTENSION
Stay in the test

The current host.
The controls needed.

Open the popup to review, add, edit, or pause headers for the site being tested. Move to the rule manager when the wider setup needs attention.

Create the first rule
Local by design

Settings stay in Chrome.

No account. No analytics. No developer uploads. Rules and header values stay in the local Chrome profile. Active headers reach matching destinations and may appear in their logs.

Read the privacy policy
Practical guides

Put the next test in motion.

01 / First rule

Modify request headers for an HTTPS API in Chrome

Create exact-host rules. Scope API paths or fetch/XHR requests. Verify in DevTools.
02 / Environments

Switch staging and QA request headers with profiles

Separate staging and QA headers. Switch profiles without retyping values.
03 / Automatic expiry

Automatically turn off temporary test headers in Chrome

Set one-hour, eight-hour, or browser-session expiry. Keep rules saved for later tests.

A few useful details.

Which headers can HeaderKit change?

Request headers on approved HTTPS hosts. HeaderKit does not edit response headers, inspect response bodies, or bypass CORS.

Does it need access to every website?

Grant exact-host access when adding a rule. Review and revoke site permissions through Site access.

Can rules turn off automatically?

Choose one hour, eight hours, or Chrome shutdown. Manual shutoff is also available.

Load from source

Clone the GitHub repository , open chrome://extensions , enable Developer mode, choose Load unpacked , and select the extension directory.

Ready when the test is.

Put headers in their place.

Free. Local settings. Chrome 120 or later.

Add to Chrome