A fast, native macOS app to inspect, mock, and reshape HTTP/S traffic in real time. Free forever. Public domain.
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Debugging network traffic on macOS shouldn't cost $89. FRTMProxy gives you the full toolkit — breakpoints, Map Local, scripting, diffing, WebSocket inspection, device setup — for free, with no limits. It's a native SwiftUI app built on top of the battle-tested mitmproxy engine, so TLS interception just works.
| FRTMProxy | Proxyman — Free | Proxyman — Paid | |
|---|---|---|---|
| Price | Free forever | Free | from $89 |
| Debugging / rewrite rules | ✅ Unlimited | ✅ | |
| Breakpoints | ✅ | ✅ | |
| Map Local | ✅ | ✅ | |
| Scripting | ✅ | ✅ | |
| Request/response Diff | ✅ | ✅ | ✅ |
| WebSocket inspection | ✅ | ❌ | ✅ |
| iOS & Android setup | ✅ | ✅ | ✅ |
| HAR import / export | ✅ | ❌ | ✅ |
| Native macOS (SwiftUI) | ✅ | ✅ | ✅ |
| Open / public domain | ✅ | ❌ | ❌ |
Proxyman feature availability and pricing per proxyman.com/pricing, as of July 2026. Proxyman is a great, more mature tool — this table is about what you get for free.
brew tap ValentinoPalomba/frtmtools
brew install --cask frtmproxyGrab the latest .zip from the Releases
page. The app is signed with a Developer ID, notarized, and auto-updates via
Sparkle.
- Inspect requests and responses with a fast, readable inspector.
- Mock local responses with no code — perfect for edge cases and isolating from backends.
- Record & replay sessions: capture traffic, export to HAR, replay recorded responses as mocks.
- Break on requests/responses to inspect or edit them on the fly.
- Connect devices: guided certificate setup for iOS simulators, physical devices (via QR), and Android.
- Capture this Mac's traffic with a one-toggle system proxy override.
- Shape traffic: simulate latency, jitter, bandwidth limits, and packet loss.
- Build rule pipelines: match traffic once, then mock, redirect, rewrite, block, delay, breakpoint, or script it with ordered actions.
- Return to earlier captures: encrypted persistent sessions keep a paged timeline with notes and bookmarks.
- Launch selective targets: route one app, Chromium/Electron profile, or CLI process through FRTMProxy without changing the system proxy.
- Inspect structured protocols: GraphQL, JWT, cookies, forms, multipart, SSE, XML/HTML, gRPC, and generic Protobuf wire payloads.
- Share a workspace: import or export versioned, Git-friendly rules, scripts, and breakpoints.
- Automate locally: expose redacted flows and atomic rule replacement through a local MCP server bound to a user-only Unix socket.
Rules — answer specific requests locally. Fast mocks, edge cases, dependency isolation.
Collections — record a session, keep it local or push it to a Git repo. Export to HAR, edit, reuse. Enable a collection to enter Replay mode: matching calls are served from recorded mocks.
Breakpoints — pause requests/responses to inspect or modify them before they continue.
Device setup — a dedicated section to connect iOS/Android: guided simulator install and a QR code to install the certificate on a physical device.
Start FRTMProxy, then choose Device → Copy MCP Server Configuration and paste the copied JSON into your MCP client. The bundled stdio launcher connects to FRTMProxy's local Unix socket. Flow headers and URLs are redacted by default, bodies are omitted by default, and the socket is accessible only to the current macOS user.
| Light | Dark |
|---|---|
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FRTMProxy is public domain and contributions are welcome. See CONTRIBUTING.md to
get started (make bootstrap, make build, make test). Maintainer release notes live in
docs/RELEASING.md.
FRTMProxy is free and will stay free. If it saves you time, a ⭐ on the repo genuinely helps it reach more developers — and if you'd like to say thanks, you can buy me a coffee.
Released into the public domain under the Unlicense. Do whatever you want with it.
Happy debugging! 🚀