Capture
Inspect requests, responses, timing phases, and matched rules without leaving the desktop.
See the request. Change the outcome.
A desktop MITM proxy for frontend engineers who need precise capture, programmable rules, repeatable replay, and browser-level debugging.
Stable channel
Checking GitHub for the newest signed macOS build.
Capture, rewrite, replay, and debugging stay together in one local workspace.
Inspect requests, responses, timing phases, and matched rules without leaving the desktop.
Redirect hosts, replace files, edit bodies and headers, inject code, simulate latency, throttle bandwidth, or return mocks.
Save requests in collections, edit them precisely, and run them again.
Inject a CDP bridge and collect console output, errors, Fetch, and XHR activity.
Dense request streams remain easy to scan. Status, protocol, timing, and rule matches stay distinct.
Explore captureGET/api/cart200POST/checkout201GET/assets/app.jsLOCALGET/profileDEBUG# route the API to a local service
api.example.com host://127.0.0.1:3000
# replace a bundle and enable browser debug
cdn.example.com/app.js file:///project/dist/app.js
example.com debug://Use Whistle-compatible patterns and actions to control upstream routing, requests, responses, local files, timing, browser injection, and plugins.
Read the rules guide