mitmproxy

mitmproxy is a free, open-source interactive proxy for inspecting, modifying, recording and replaying network traffic. Developers, testers and network engineers can use it to investigate applications and services in environments they control. It includes mitmproxy, a terminal interface; mitmdump, a command-line tool for scripted processing; and mitmweb, a browser-based interface.

Features

• Inspect HTTP and HTTPS requests and responses, including HTTP/2 and WebSocket traffic.
• Intercept and edit messages, then resume requests to examine application behavior.
• Record traffic flows, filter and annotate them, and replay client or server flows.
• Export traffic for further analysis, including HAR workflows.
• Extend processing with Python addons and configurable options.
• Use supported proxy modes for different network setups; protocol capabilities depend on the chosen mode.

Installation and first use

Install brew install --cask mitmproxy, the official recommended macOS method, or download the architecture-specific standalone archive. The Homebrew cask links mitmproxy, mitmdump and mitmweb executables into Homebrew's bin directory; it is a command-line tool distribution rather than a conventional draggable GUI application. Start mitmproxy in a terminal, or mitmweb for its local browser UI. Configure your test client to use the listening proxy; regular proxy mode ordinarily listens on port8080, and mitmweb uses a separate web interface. Change ports if another local service already uses them.

For HTTPS inspection, the test client must trust the mitmproxy CA generated for your installation. The official certificates guide explains installing trust on each platform. A browser can visit mitm.it through the configured proxy to obtain the appropriate certificate. Certificate pinning or an application-specific trust store can still prevent interception. Return your client proxy and trust settings to the desired state when finished. Recorded traffic and the CA private key in ~/.mitmproxy can contain sensitive material; retain only what you need for your testing workflow.

Requirements and dependencies

The official standalone binaries include a self-contained Python3 environment, OpenSSL and other dependencies. You do not need to install Python separately for this cask. The version12.2 line's binary environment moved to Python3.14. Addons requiring extra Python packages may need a separate PyPI/uv installation with those packages rather than modifying the frozen standalone bundle. Dependencies inside a binary release cannot be updated independently; update mitmproxy to obtain newer bundled dependencies.

The cask provides macOS Apple Silicon and Intel archives and declares no extra formula dependency. Its listed macOS platforms include Big Sur and newer, but the retrieved upstream installation guide does not give an independent numeric macOS minimum; do not treat a cask platform list as a guarantee for every older OS. Official Linux standalone binaries and Windows installer/binaries are also available. On Windows, the publisher recommends Windows Terminal and also supports WSL. Linux distribution packages are community-maintained and can lag upstream. This catalog's default download is the macOS ARM64 archive. No fixed RAM or disk-space minimum was confirmed; capture volume and stored flows affect resource use. Archive download size is not installed space.

Conflicts and cleanup

Homebrew declares no named cask conflict. Existing executables with the same names, another proxy on the same port, or client VPN/proxy routing can affect operation. mitmproxy does not automatically capture every process: select and configure a suitable proxy mode for the traffic you want to test. Some TLS failures reflect client trust, pinning or certificate configuration rather than an installation error. Optional Homebrew zap deletes ~/.mitmproxy, including settings, generated CA material and retained files there; back up data you need first.

Accounts, costs and license

mitmproxy is free software under the MIT license, maintained by the mitmproxy project and contributors. Core local use does not require a paid subscription or hosted-service account. Third-party services you connect to keep their own credentials and charges. The project accepts sponsorship. The official installation documentation states that mitmproxy does not phone home or perform automatic update checks.

Official references

• Installation and bundled dependencies
• Certificates
• Official downloads
• Source and MIT license
• Version-specific changelog