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httpmon
What it is
httpmon is a free terminal proxy for debugging HTTP and HTTPS traffic on Linux and macOS. It intercepts requests and responses and displays them in real time, with methods and status codes color-coded. HTTPS interception automatically creates CA certificates, allowing decrypted headers, bodies and timing to appear as plain text. The proxy decodes gRPC, gRPC-Web and Protobuf bodies into readable JSON, including wire-format fields when no .proto file is available. Vim-style navigation and filters by host, path, method or status code help narrow traffic. Users can inspect, compose, repeat and compare requests, copy them as cURL, and edit traffic with JavaScript hooks or breakpoint rules. Throttling presets, local-file serving, response mocking and HAR export are included. An MCP server can expose captured traffic to LLM agents. The FAQ says it runs over SSH, in Docker and in CI, starts in milliseconds and uses about 20 MB of RAM. The Free plan is free, MIT licensed, with no account or paid tiers.
For and against
For
- Real-time request and response inspection
- Readable gRPC and Protobuf decoding
- Request editing, replay and comparison
- HAR export and MCP integration
- Runs over SSH, Docker and CI
Against
- HTTPS data is shown decrypted in plain text
- Linux and macOS platforms only
- No paid tiers or free trial
The verdict
httpmon combines traffic inspection, editing and replay in a terminal-based proxy. Its protocol decoding, filtering and automation hooks support detailed debugging workflows.
Who it suits
It suits developers who debug network traffic from a terminal on Linux or macOS. It also fits workflows using SSH, containers, CI or MCP-connected agents.
Plans and prices
Free
MIT license · no paid tiers · no account needed
Read 8 Oct 2026 · httpmon.dev
On the record
- Export
- Captured flows can be exported in HAR format.httpmon.dev · read 8 Oct 2026
- HTTPS interception
- httpmon automatically generates CA certificates to decrypt HTTPS traffic for inspection.httpmon.dev · read 8 Oct 2026
- Live inspection
- Requests and responses appear in real time with methods and status codes color-coded.httpmon.dev · read 8 Oct 2026
- MCP integration
- An MCP server can expose captured traffic to LLM agents via the Model Context Protocol.docs.httpmon.dev · read 8 Oct 2026
- Navigation and filtering
- It supports vim-style navigation and filtering by host, path, method, or status code.httpmon.dev · read 8 Oct 2026
- Protocol decoding
- It decodes gRPC, gRPC-Web, and Protobuf bodies as readable JSON, including wire-format fields when no .proto files are provided.httpmon.dev · read 8 Oct 2026
- Purpose
- httpmon is a terminal HTTP/HTTPS debugging proxy that intercepts traffic so users can inspect and modify requests and responses.httpmon.dev · read 8 Oct 2026
- Request tools
- Users can inspect headers and bodies, compose or repeat requests, copy requests as cURL, and compare requests side by side.httpmon.dev · read 8 Oct 2026
- Resource use
- The FAQ says it starts in milliseconds and uses about 20 MB of RAM.httpmon.dev · read 8 Oct 2026
- Security detail
- The site says HTTPS traffic is decrypted and its headers, bodies, and timing are shown in plain text.httpmon.dev · read 8 Oct 2026
- Supported platforms
- The FAQ specifies macOS for Apple Silicon and Intel, and Linux for arm64 and amd64.httpmon.dev · read 8 Oct 2026
- Traffic controls
- JavaScript hooks can modify requests and responses; httpmon also supports throttling presets and serving local files.httpmon.dev · read 8 Oct 2026
- Where it runs
- The FAQ says httpmon works over SSH, in Docker containers, and in CI anywhere a terminal is available.httpmon.dev · read 8 Oct 2026
