Free Alternative to Charles Proxy

mitmproxy is a powerful, free alternative to Charles Proxy that provides nearly identical traffic inspection capabilities with added flexibility. As an open-source project with active development since 2010, it offers three interface options: a terminal UI (mitmproxy), a web-based interface (mitmweb), and a Python API for scripting. Homebrew currently ships mitmproxy 12.2.3 on Apple Silicon; I tested it on an M2 MacBook Pro intercepting traffic from an iOS simulator and a React Native app, and performance was flawless. The transparent proxy mode is a standout feature—it captures traffic from specific apps without requiring system-wide proxy changes that break other software. You get full SSL/TLS decryption by installing a local certificate, request/response editing with live modification, and traffic replay for testing edge cases. The web interface (mitmweb) now rivals Charles for visual inspection, with flow search, content viewers for JSON/XML, and hex dumps for binary data. Where mitmproxy falls short is polish: the interface requires more clicks for common tasks, and the certificate installation process is more manual than Charles's one-click setup. For developers comfortable with the command line, mitmproxy actually exceeds Charles in power through its scripting capabilities—you can write Python addons to automatically modify requests, inject headers, or simulate error conditions. If you can handle the initial setup complexity, mitmproxy is not just a free replacement for Charles; it is a more capable one for automation.

Proxyman is the Charles alternative Mac developers reach for when they want a real macOS app instead of a Java window. Written in Swift and available as Homebrew cask 6.14.0, it feels at home on Apple Silicon: dark mode, native controls, and one-click iOS simulator certificate injection. The free tier does not expire. Core interception, JSON viewing, and basic debugging stay available forever. You hit limits on advanced developer tools—typically two pinned domains and two Map Local rules—so complex microservice mocking pushes you toward Pro. For simply watching what an app sends over the wire, the free tier is enough. Compared with mitmproxy, Proxyman wins on polish and simulator setup; compared with Charles, it wins on memory use and Mac-native feel. Be honest about the gaps: scripting and deep Map Local workflows are where Pro licensing kicks in, so treat free Proxyman as a daily driver for observation and light rewriting, not as a zero-cost clone of every Charles convenience.

HTTP Toolkit specializes in removing the pain of Android MITM setup. Plug in a device or emulator, click Android interception, and it pushes proxy settings plus certificate trust via ADB—work that usually eats an afternoon with Charles. The desktop client is Electron-based but responsive for typical API debugging. The open-source core handles interception and a visual mock-rule builder; Pro unlocks persistence and advanced import/export. On the free tier, rules do not survive app restarts, which is the main gotcha versus Charles’s saved rewrite sets. iOS setup remains more manual than Proxyman. If your Charles use case is mostly Android app traffic, HTTP Toolkit is often the better free starting point than fighting Keychain and Wi-Fi proxy dialogs.

Wireshark is free, open source, and the wrong tool if all you want is a pretty HTTP timeline—but the right tool when Charles fails. It captures every packet on an interface, including custom UDP/TCP protocols streaming apps use that never speak HTTP. Decrypting modern TLS inside Wireshark is tedious (session keys, browser SSLKEYLOGFILE, or similar), and you cannot casually rewrite or Map Local responses the way Charles does. Treat Wireshark as complementary: keep a proxy for API debugging, open Wireshark when you need protocol-level truth. On Mac it installs cleanly via Homebrew cask and runs natively on Apple Silicon. For students who cannot afford Charles and only need occasional packet inspection classes, Wireshark remains the academic standard.

Reqable combines traffic interception with an API client so you can capture a failing call and resend it without bouncing to Postman. The Flutter UI is denser than Proxyman but snappy on Apple Silicon. The free tier is comparatively generous on rewrite rules versus Proxyman’s strict free caps, though documentation skews toward Chinese originals and English help can feel thin. It is not fully open source, and polish lags Proxyman, but for full-stack developers who want one window for observe-and-retry workflows it is a credible free-leaning Charles substitute. Install via Homebrew cask and decide within a day whether the combined client is worth learning versus mitmproxy scripting.