HTTP Header Injector — add custom HTTP request headers in Chrome

FREE MODHEADER REPLACEMENT

Add custom request headers. Nothing else.

ModHeader disappeared from the Chrome Web Store. HTTP Header Injector covers the essentials profiles for prd/stg/local, per-header toggles, URL filtering, JSON export/import and deliberately stays out of your way otherwise.

Add to Chrome View source on GitHub

Pending Chrome Web Store review - install a dev build from GitHub in the meantime.

Manifest V3 No data collected Request headers only

Request Headers - api.example.com

Accept:application/json

User-Agent:Mozilla/5.0 (...) Chrome/126

Authorization:Bearer •••••••••••••

X-Env:staging

WHAT IT DOES

Everything ModHeader users actually used

No response-header editing, no bundled telemetry, just the request-header workflow, done well.

NEW

Profiles (prd / stg / local)

Keep a separate header set per environment or app, then switch the active profile in one click. Just like ModHeader's profiles.

Add request headers

Set a header name and value. It's attached to every matching outgoing request.

Per-header toggle

Switch any single header on or off without deleting it.

URL filter

Limit headers to requests whose URL contains specific text or leave it blank to apply everywhere.

Explicit save

Nothing takes effect until you click Save - no surprise edits mid-request.

Import / export JSON

Back up your header set as a file, or hand it to a teammate to load into their own browser.

Local storage only

Everything lives in chrome.storage.local. No external server, ever.

HOW IT WORKS

Three steps, no account required

From install to your first injected header in under a minute.

Add a header

Open the popup, click "+ Add", and enter a header name and value. e.g. Authorization / Bearer xxxxx.

Filter (optional)

Enter text in the URL filter field to target specific requests, or leave it blank to apply to everything.

Save

Click Save to apply your changes. Nothing is active until you do.

IMPORT / EXPORT

Your setup, as portable JSON

Every profile - its headers, values, and URL filter - exports to a single JSON file. The same format the popup imports back in, so you can share a whole prd/stg/local setup with a teammate.

Export creates a plain JSON file you can keep or version-control
Import stages it in the popup - review before you save
The file only ever touches your disk - nothing is uploaded

1{
"urlFilter": "*://api.example.com/*",
"headers": [
  {
    "id": "h_a1b2c3d",
    "enabled": true,
    "name": "X-Env",
    "value": "staging"
  },
 {
   "id": "h_x9y8z7w",
   "enabled": true,
   "name": "Authorization",
   "value": "Bearer {{token}}"
 }
]
17}

Get it in a few seconds

Free, open source, and it never phones home.

Add to Chrome View source on GitHub