httpmon vs Fiddler
The Best Open-Source
Fiddler Alternative
A 15 MB Go binary instead of an Electron app. Free, open source, with gRPC support.
Why switch from Fiddler to httpmon?
Classic Fiddler was Windows-only. Fiddler Everywhere fixed that by wrapping everything in Electron — so now it runs everywhere but eats 300+ MB of RAM and requires a Telerik account. httpmon does the same HTTP debugging in your terminal without the overhead.
Feature Comparison
| Feature | httpmon | Fiddler |
|---|---|---|
| Price | Free (MIT) | Free tier / $12+/mo |
| Open source | ✅ Full source on GitHub | ❌ Proprietary |
| macOS support | ✅ Native binary | ⚠️ Fiddler Everywhere (Electron) |
| Linux support | ✅ Native binary | ⚠️ Fiddler Everywhere (Electron) |
| Terminal-native | ✅ Runs in terminal | ❌ GUI only (Electron/.NET) |
| Vim keybindings | ✅ Full vim navigation | ❌ Mouse-driven |
| HTTPS interception | ✅ Auto CA certs | ✅ |
| gRPC decoding | ✅ Built-in | ❌ Not supported |
| Protobuf decoding | ✅ Built-in | ❌ Not supported |
| HAR export | ✅ | ✅ |
| Scripting | ✅ JavaScript hooks | ✅ FiddlerScript |
| Network throttling | ✅ Built-in presets | ✅ |
| MCP server (AI) | ✅ --mcp flag | ❌ |
| Diff view | ✅ Side-by-side | ❌ |
| SSH/headless | ✅ Works over SSH | ❌ Requires display |
| Memory usage | Low (~20 MB) | High (Electron ~300+ MB) |
| Account required | No | Yes — Telerik account |
What makes httpmon different
Not an Electron app
Fiddler Everywhere ships Chromium to debug HTTP. httpmon is a 15 MB Go binary that uses ~20 MB of RAM.
No account, no subscription
Fiddler wants a Telerik account and pushes paid plans. httpmon works offline, no sign-up, MIT license.
Stays in your terminal
Vim keybindings, keyboard-driven filtering and inspection. If you already use the terminal for everything else, httpmon doesn't make you switch windows.
gRPC & Protobuf decoding
Fiddler can't decode gRPC or Protobuf. httpmon handles gRPC, gRPC-Web, and Protobuf natively.
FAQ
Frequently Asked Questions
Does httpmon work on macOS and Linux?
Native binaries for both. macOS (Apple Silicon + Intel) and Linux (arm64 + amd64). No Electron, no .NET — just a Go binary you can run anywhere.
Is httpmon lighter than Fiddler Everywhere?
By a lot. Fiddler Everywhere is an Electron app — 300+ MB of RAM. httpmon uses ~20 MB and starts in milliseconds.
Do I need an account to use httpmon?
No account, no login, no internet connection required. Fiddler Everywhere makes you create a Telerik account before you can do anything.
Does httpmon support gRPC and gRPC-Web? Fiddler doesn't.
Fiddler has no gRPC or Protobuf support. httpmon decodes gRPC, gRPC-Web, and Protobuf natively — useful if you're working with microservices or mobile backends.
Can httpmon modify requests and responses like Fiddler?
JS scripting with onRequest() and onResponse() hooks. Inject headers, change status codes, rewrite bodies.