A tiny single-purpose Chrome extension: add custom HTTP request headers to browser requests Chrome lets extensions modify. Nothing else.
No build step, no background worker, no dependencies — just a manifest, a popup, and one declarativeNetRequest dynamic rule that Chrome enforces natively. Headers keep being injected even after a browser restart, without the extension's code running.
- Open
chrome://extensions - Enable Developer mode (top right)
- Click Load unpacked and select this folder
Click the extension icon and add header name/value pairs — every change saves and applies immediately. The checkbox next to each row enables/disables that header individually. Settings persist across restarts.
To verify it works, open https://httpbin.org/headers — your headers should appear in the echoed request. Note: DevTools' Network panel may not show headers injected this way, so use an echo endpoint to check.