Modify request headers

Use a request-header rule to change headers before the browser sends a matching request.

1. Create or select a modifyHeaders profile.

2. Add Modify request header if the profile does not already contain it.

3. Enter the header name.

4. Choose an operation:

   • set to create or replace the value;
   • append to add a value to an allowed request header;
   • remove to delete the header.

5. Enter a non-empty value for set or append.

6. Add conditions that limit the affected requests.

7. Reload the target page and inspect the request in Developer Tools.

Append is restricted

Chrome permits append only for a fixed, case-sensitive list of request-header names. Use set when the header is not on that list. See Modify headers reference.

When profiles modify the same header, set explicit priorities and verify the final request.