Get started

PostGate is a local desktop proxy for inspecting and rewriting HTTP and HTTPS traffic. Capture, Whistle-compatible rules, request replay, browser debugging, and sandboxed plugins all live in one app.

Install PostGate

Download PostGate for macOS from the PostGate home page. Choose the Apple silicon or Intel build; the download links point directly to the matching file in the latest GitHub Release.

• macOS: open the .dmg and move PostGate to Applications.
• Windows: the native build is in preparation and marked Coming soon on the download page.

PostGate listens only on localhost by default. The default proxy address is 127.0.0.1:8899.

Capture your first request

1. Open Capture and press Start.
2. Set the HTTP proxy in the browser or operating system to 127.0.0.1:8899.
3. Visit an HTTP page in that browser.
4. Select the request in PostGate to inspect the request and response headers, bodies, and timing.

For HTTPS traffic, install and trust the PostGate root certificate before browsing HTTPS pages.

Add your first rule

Open Rules, create a rule group, and add:

Text
api.example.com host://127.0.0.1:3000

Enable the group. Requests to api.example.com now keep their original URL while PostGate connects to the local service on port 3000.

To return a fixture instead:

Text
api.example.com/v1/user file:///absolute/path/to/user.json

The parse status below the editor reports syntax errors and flags protocols that PostGate recognizes but does not yet support.

Where to go next

• Capture traffic to filter requests, inspect bodies, and export sessions.
• Rules for matching and actions.
• Debug for console, page errors, Fetch, XHR, and CDP connections.
• Replay to save, edit, and repeat requests.
• Plugins for JavaScript request and response handlers.