Apps similar to Charles include Fiddler, which has a free version. Other options are mitmproxy, HTTP Toolkit, Burp Suite and Proxyman. There's no shortage of HTTP(S) Debuggers like Charles, with more than 25 alternatives for Mac, Windows, Linux, iPhone and iPad.
Slowy is an OSX app which simulates custom connection's conditions and limits the network traffic. It is created for web developers that work on a local server, to test a website with a real-world connection.
A lightweight macOS menu bar app for simulating poor network conditions instantly. Test your apps on 3G, Edge, high latency, or packet loss system-wide with a single click.
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HttpFox monitors and analyzes all incoming and outgoing HTTP traffic between the browser and the web servers.
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Uthrottle is a tool which simulates custom connection’s conditions and limits the network traffic to a specified speed on network interfaces. In complex service oriented application stacks, some bugs only manifest themselves on congested or slow
HTTP Scoop is a Mac network sniffer that displays requests to websites along with the response, and makes it fairly easy to see what's going on.
ReqRes is an open-source, high-performance, modern native web debugging proxy for macOS. It lets you capture, inspect, modify, and intercept HTTP(S) traffic in real time.
A macOS and iOS tool from Apple for simulating poor network conditions such as 3G, Edge, and packet loss during app development.
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Built from the ground up for mobile developers. Monitor network requests, logs, and events in real-time. Debug faster, ship with confidence.
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Free native HTTPS debugging proxy for Mac (Linux beta) with a built-in API client and an MCP server for AI coding assistants.
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Interceptor is a local-first desktop HTTP/HTTPS proxy for authorized security testing, traffic capture, replay, diagnostics, and evidence-ready reporting.
Modern HTTP debugging tool, Debug, mock, and rewrite HTTP/HTTPS traffic with composable rules.
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