Apps similar to HTTP Toolkit include Insomnia REST Client, which is open source with a free version. Other options are Fiddler, mitmproxy, Hoppscotch and Burp Suite. You're spoiled for choice with API Clients like HTTP Toolkit: we list more than 50 alternatives for Mac, Windows, Linux, the web and iPad.
Lama2 defines the human-friendly l2 syntax and CLI for describing and executing APIs. Store your APIs in plain-text files. Collaborate with team using version control (say, git). Run Lama2 directly from VSCode extension. Think of Lama2 as Markdown for APIs.
Send HTTP requests to API endpoints. GetIt's main focus is to make your life a lot easier when you have to test APIs or use somebody else's API.
Built from the ground up for mobile developers. Monitor network requests, logs, and events in real-time. Debug faster, ship with confidence.
Germany
EU
apikumo is an API workspace that combines an API client, a hosted documentation site, and a live MCP (Model Context Protocol) endpoint in one place. Design your API once, and every AI agent can call it.
Easy, intuitive yet powerful HTTP(S) debugging proxy for macOS, Windows and Linux — capture, inspect, mock, break and replay traffic.
GermanyEU
Resonance is a local-first, zero-account API client application designed to provide an excellent user experience for testing and interacting with APIs. Built with Tauri, it offers a modern and intuitive interface for developers.
Free, open-source Fiddler Classic alternative for Windows. Capture, inspect, filter, replay, compose and mock HTTP/HTTPS traffic with TLS decryption, HTTP/2, HTTP/3 and SAZ support.
Modern HTTP debugging tool, Debug, mock, and rewrite HTTP/HTTPS traffic with composable rules.
United States
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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