Documentation

Start

MockHeader compiles your profile into Chrome declarativeNetRequest rules. It does not proxy traffic.

Install from source

Terminal

git clone https://github.com/nightsumx/MockHeader.git
cd MockHeader
bun install
bun run build

Open chrome://extensions, turn on Developer mode, Load unpacked, pick output/chrome-mv3.

Add a header

Open the popup. Request headers are the first block. Type a name and a value. Chrome applies set unless you switch the row to append or remove.

Use a custom name such as X-MockHeader-Test when you want to see it on httpbin.org/headers. Chrome silently drops some names (Host, Connection).

Limit where it runs

Without a filter, a live profile matches every request. Add a URL filter (this page / this host / this domain) or a tab / window / resource / time filter.

Redirect

From is a Chrome URL filter (*://httpbin.org/get). To is the destination. Regex uses Chrome regex substitution.

Export downloads JSON and copies a share string. Import accepts that file or string.

Develop