httpmon

httpmon

Terminal-native HTTP/HTTPS debugging proxy. Intercept, inspect, and filter traffic — all from your terminal with vim-style navigation.

Think Proxyman or Charles, but in your terminal.

Features

• MITM proxy — Intercept HTTP and HTTPS traffic with auto-generated CA certificates
• Live flow list — Watch requests stream in real-time with color-coded methods and status codes
• Detail inspector — Drill into any request/response: headers, bodies, timing
• Quick filter — Type / to filter flows by host or path instantly
• Keyboard-driven — Vim-style navigation (j/k/Enter/Esc) — no mouse required
• Body capture — Request and response bodies captured up to 5MB

Quick Start

Install from source

go install github.com/kostyay/httpmon/cmd/httpmon@latest

Build locally

git clone https://github.com/kostyay/httpmon.git
cd httpmon
make build
./httpmon

Usage

httpmon                    # Start proxy on :8080
httpmon --port 9090        # Custom port
httpmon --install-ca       # Install CA cert into system trust store (needs sudo)
httpmon --version          # Print version

Then configure your browser or app to use http://localhost:8080 as its HTTP proxy.

Trust the CA certificate

The easiest way — run once with sudo:

sudo httpmon --install-ca

This generates the CA cert (if it doesn't exist yet) and adds it to your system trust store. Supports macOS and Linux.

sudo security add-trusted-cert -d -r trustRoot \
  -k /Library/Keychains/System.keychain ~/.httpmon/mitmproxy-ca-cert.pem

sudo cp ~/.httpmon/mitmproxy-ca-cert.pem /usr/local/share/ca-certificates/httpmon.crt
sudo update-ca-certificates

Keyboard Shortcuts

Flow List

Detail View

Architecture

cmd/httpmon/       CLI entry point, flag parsing, wiring
internal/proxy/    MITM proxy engine (go-mitmproxy wrapper)
internal/store/    Thread-safe ring buffer for captured flows
internal/filter/   Quick substring filter
internal/tui/      Bubble Tea terminal UI

Built with go-mitmproxy and Bubble Tea.

Contributing

make all        # lint + test + build
make test       # tests with race detection
make lint       # golangci-lint
make security   # gosec, govulncheck, gitleaks, trufflehog

License

MIT