mitmproxy

mitmproxy is a free toolkit for examining and changing web traffic, best suited to developers and other technically confident users who need control over HTTP conversations. Its combination of editing, recording, replay, and multiple proxy modes makes it a strong fit for debugging; HTTP/3 replay and frozen dependencies in packaged releases are meaningful caveats.

Overview

mitmproxy handles HTTP/1, HTTP/2, and WebSocket traffic, including SSL/TLS traffic. It can intercept requests and responses as they pass through a proxy, making it possible to inspect or modify exchanges rather than treating them as opaque network activity. A certificate authority implementation generates interception certificates on the fly.

Three interfaces address different working styles: mitmproxy is an interactive console, mitmweb provides a browser-based GUI, and mitmdump produces non-interactive terminal output. That choice makes the toolkit adaptable, though users still need to understand proxy setup and certificate interception to make effective use of it.

Readers comparing tools can browse Web Debugging Proxies, Forward Proxy Software, or the broader Proxy Software category.

Key features

Inspect, edit, and replay

Requests and responses can be modified in transit, with breakpoint rules for selective interception. mitmproxy can save HTTP conversations for later analysis and replay client requests or previously recorded server responses. Response mocking and WebSocket inspection extend its usefulness for debugging workflows that need to examine more than a single live exchange. These capabilities provide substantial control, but they are geared toward traffic analysis rather than a simple set-and-forget proxy.

Many ways to route traffic

Modes include regular, local capture, WireGuard, reverse, transparent, TUN, upstream, SOCKS5, and DNS. This range gives technical users options for different network arrangements. WireGuard can capture traffic from external devices or individual Android apps, which is useful when the target traffic originates beyond the machine running the proxy.

Python customization

Python addons can respond to events, change proxy behavior, and expose commands for users to invoke. This is a practical advantage for workflows that need repeatable or tailored handling; it also makes the tool a better fit for users comfortable working with Python than for those seeking configuration-free inspection.

Protocol and update caveats

The documentation says HTTP/3 client replay is currently broken, and HTTP/3 support has been extensively tested only with cURL. Teams relying on HTTP/3 replay should look elsewhere or account for that limitation. The project also says it does not phone home or check for updates, but dependencies bundled in precompiled binaries and Docker images are frozen at release and cannot be updated in place. Regularly updating those releases matters for users who depend on bundled components.

Pricing

mitmproxy is free and open source. The mitmproxy plan costs nothing and includes request and response editing, breakpoint rules, traffic replay, response mocking, WebSocket inspection, and proxy chaining. There are no paid tiers or seat and quota limits described for this plan, making it accessible for individual use as well as technical teams that can manage their own deployment.

Platforms

mitmproxy supports Linux, macOS, Windows, self-hosted use, and web access through mitmweb. Installation is documented for Windows, macOS, and Linux; PyPI installation and official Docker images are also offered. The project’s no-update-check behavior may suit users who prefer not to have software check in, while the frozen dependencies in packaged binaries and Docker images call for a deliberate update routine.

Who it's for

mitmproxy is a good choice for developers, security and network practitioners, and other technical users who need to inspect, edit, record, or replay HTTP traffic. The range of proxy modes, browser and console interfaces, and Python addons make it particularly useful when one workflow must accommodate different traffic sources or custom behavior. It is less suitable for users who want a managed service, minimal configuration, or dependable HTTP/3 client replay.

Usage questions, contributions, and bug reports are directed to GitHub. The project names Aldo Cortesi as founder and lists Maximilian Hils and Thomas Kriechbaumer among its developers.

Pros and cons

• Pros: Free and open source, with request and response editing, replay, mocking, WebSocket inspection, and proxy chaining included.
• Pros: Three interfaces and a broad set of proxy modes suit varied traffic-inspection workflows.
• Pros: Python addons allow custom event handling and user-invoked commands.
• Cons: HTTP/3 client replay is currently broken, limiting workflows that depend on it.
• Cons: Dependencies in precompiled binaries and Docker images cannot be updated in place, so users must keep releases current.
• Cons: The broad configuration and certificate-interception capabilities are aimed at technically confident users, not people seeking a turnkey proxy.

Alternatives

Cloudflare Gateway is worth considering for readers seeking a freemium service with a free plan for 50 users and standard log retention of up to 24 hours, rather than mitmproxy’s free, open-source inspection toolkit.

3proxy, Privoxy, and Squid are free proxy alternatives; choose among them when you want to evaluate another open-source or self-hosted option.

Skyhigh Private Access is a paid alternative. WinGate is a freemium Windows option whose Standard plan is priced by concurrent users, with a 6-user plan at $109.95 a month. SafeSquid Secure Web Gateway is a paid option with an annual subscription that stops working if not renewed. Zscaler Private Access is a paid alternative with no free plan.

Verdict

Choose mitmproxy if you need a free, flexible toolkit for inspecting and changing HTTP traffic, with replay, multiple interfaces, and extensive proxy modes.