Free Alternative to Charles

Proxyman (Homebrew cask 6.14.0) is the app that made me finally uninstall Charles. It is written entirely in Swift. The performance difference is immediately obvious. I loaded a 250MB HAR file containing a massive GraphQL query log, and Proxyman parsed it instantly. The interface looks like a modern Apple app, complete with dark mode and native window controls.

I love how it handles iOS simulators. A single click in the menu bar installs the root certificate into your active Xcode simulator. No more dragging and dropping certificates or digging through iOS settings menus. The free version is technically a trial, but it does not expire. You hit a paywall only if you need advanced features. The free tier limits you to two pinned domains and two active Map Local rules. I hit this limit quickly when debugging complex microservices. You have to constantly delete old rules to make room for new ones.

Despite the rule limits, the core interception features are entirely unrestricted. The JSON viewer is gorgeous. It auto-formats messy responses and lets you copy individual keys with a right-click. If you just need to see what your app is sending over the wire, the free version is more than enough.

I avoided mitmproxy for years because I wanted a graphical interface. That was a mistake. This Python-based tool runs entirely in your terminal. Once you learn the keyboard shortcuts, it is the fastest way to manipulate network traffic on a Mac.

I tested mitmproxy 12.2.3 on my M3 Mac. Because it lacks a heavy GUI, it barely registers on Activity Monitor. The real power lies in its scriptability. I needed to add a custom authentication header to every request matching a specific regex pattern. I wrote a six-line Python script, pointed mitmproxy at it, and it worked perfectly. You cannot do that easily in Charles.

mitmproxy intercepts HTTP/2 and WebSockets flawlessly. It also includes a web-based interface (mitmweb) if you really need to use a mouse, but the web UI feels barebones compared to a native app. The terminal interface takes about a day to get used to. You navigate flows with your arrow keys and press 'enter' to inspect payloads. It is not pretty. It is incredibly effective.

HTTP Toolkit feels like magic when you are working with Android devices. Intercepting Android traffic usually involves fighting with ADB commands and patching network security configs. I plugged a Pixel 6 into my Mac, opened HTTP Toolkit, and clicked the 'Android Device' button. It automatically pushed the proxy settings and injected the system certificate. I was reading encrypted app traffic in ten seconds.

The desktop app is built on Electron. I usually hate Electron apps for being slow, but HTTP Toolkit performs well. The developers clearly spent time optimizing the UI rendering. The interface is split into a simple interceptor and a rule builder. You can mock responses visually without writing scripts.

It is entirely open-source under the hood. They monetize by offering a Pro tier for advanced validation and importing/exporting tools. The free version handles basic interception, but you cannot save your mock rules between sessions. If you close the app, your rules disappear. This is frustrating if you have a complex local testing environment.

Reqable surprised me. It is built using Flutter. Cross-platform UI frameworks usually feel out of place on macOS, but Reqable is snappy and responsive. The developers looked at the typical developer workflow and realized we constantly switch between Postman to send requests and Charles to monitor them. Reqable puts both tools in the same window.

I captured a failing API request from an iOS simulator. With one click, I sent that exact request to Reqable's API client tab. I modified the JSON payload, fired it back to the server, and watched the response. It removes so much friction from the debugging process.

The free tier is generous compared to Proxyman. You do not hit annoying rule limits immediately. However, the UI is quite dense. It throws a lot of icons and panels at you right away. It took me a good twenty minutes to figure out how to simply map a local file to a domain. The documentation is mostly translated from Chinese and lacks detailed examples for complex use cases.

If you refuse to pay for software and you want a graphical interface, ProxyPin is your best option. It is a 100% free, open-source project hosted on GitHub. Like Reqable, it is built with Flutter. Unlike Reqable, there is no premium tier or Pro version holding back features.

I tested the macOS version to debug a React application. It captures traffic reliably. The request rewrite feature works exactly like Charles. You can modify headers, swap out hostnames, or block requests entirely. It even has mobile apps for iOS and Android, allowing you to run the proxy directly on the phone rather than routing through your Mac.

The catch is the polish. ProxyPin feels like a hobby project. The English translations in the app are rough. Sometimes the UI stops updating if you leave it running overnight, requiring a force quit. It does not handle massive PCAP files well. When I tried to load a gigabyte of captured traffic, the app simply crashed. Keep your sessions small, and it works perfectly.

Whistle is massive in the Chinese web development community but largely ignored in the West. I installed it via npm and fired up its local web server. Instead of a native app, you configure Whistle entirely through a browser tab on localhost:8899.

Whistle operates using a text-based rule system that looks exactly like a host file or an Nginx configuration. I wanted to map a production JavaScript file to my local machine. I literally typed `https://example.com/app.js file:///Users/me/local.js` in the rules tab. That was it. No menus, no popups. It is incredibly fast for frontend developers who prefer typing configurations over clicking through menus.

The web UI is strictly functional. It feels like a developer tool from 2012. You have to install a companion Chrome extension to get the most out of it. It also requires Node.js to be installed on your Mac. If you are a frontend developer already living in the Node ecosystem, Whistle fits perfectly into your workflow.

Caido is technically positioned as a replacement for Burp Suite, targeting the cybersecurity crowd. I tested it purely as an HTTP debugging proxy, and I was blown away by its efficiency. It is written in Rust. The memory footprint on my Mac never exceeded 50MB, even with thousands of requests flowing through it.

Caido uses a web-based interface, but it feels incredibly modern and responsive. The search functionality is the best I have tested. If you need to find a specific JSON key buried in an hour of captured traffic, Caido's query language finds it instantly. You type simple queries like `req.method:POST and resp.status:500`.

The free tier is heavily restricted for infosec features, but totally fine for basic API debugging. However, it lacks simple tools that Charles users expect. There is no easy 'Map Local' button. You have to use their 'Automate' tab to write rules that intercept and replace responses. It is a powerful tool, but it requires a mindset shift.

Including Wireshark in a list of Charles alternatives is a bit like comparing a scalpel to a microscope. Wireshark operates at a much lower network level. It does not just capture HTTP traffic. It captures every single packet hitting your Mac's network interface.

I use Wireshark when Charles and Proxyman fail. I was debugging a video streaming app that used a custom UDP protocol. HTTP proxies cannot see that traffic. Wireshark captured it perfectly. I could inspect the raw hex dumps of the video packets.

Using Wireshark for simple API debugging is a terrible idea. The interface is overwhelming. You have to write complex display filters just to hide background macOS noise. Setting it up to decrypt modern TLS traffic requires exporting session keys from your browser via terminal variables. It is difficult, frustrating, and absolutely essential when you are dealing with non-HTTP protocols.