Scripts and constants

Scripts execute JavaScript in the same tunnel as rewrite rules, scoped by host. Use them for branching, combined transformations, or scheduled work. Prefer rewrite rules for a single header, body, or mock change.

Create a script

1. Open Scripts and tap +. Set a name and host scope.
2. Choose Before Request, After Response, or a scheduled trigger.
3. Write the logic. Helpers such as $utils provide gzip/gunzip.
4. Save, enable the script, and turn on the global Scripts gate. Resend traffic to verify.

Constants

Store a mock JSON, token, or test URL as a constant and reference it from expert-mode rules with ${constantId}. Changing the constant updates every reference. Simple-mode Mock already assembles the response, so constants matter most when several expert rules share a value.