xh is a friendly and fast tool for sending HTTP requests. It reimplements as much as possible of HTTPie's excellent design, with a focus on improved performance.

Mock by intercepting requests on the network level. Seamlessly reuse the same mock definition for testing, development, and debugging.

Fast, easy and reliable testing for integrating web apps, APIs and microservices. Pact is a code-first tool for testing HTTP and message integrations using contract tests. Contract tests assert that inter-application messages conform to a shared understanding that is documented in a contract. Without contract testing, the only way to ensure that applications will work correctly together is by using expensive and brittle integration tests.

A free, online, open source API request builder

Smocker (server mock) is a simple and efficient HTTP mock server. Smocker exposes a configuration user interface and a configuration api to register new mocks.

A simple HTTP Request & Response Service.

Use your unique endpoint wherever you need. We'll store the details of any HTTP request and display them below.

HTTPie—aitch-tee-tee-pie—is a command line HTTP client with an intuitive UI, JSON support, syntax highlighting, wget-like downloads, plugins, and more

GoAccess is an open source real-time web log analyzer and interactive viewer that runs in a terminal in *nix systems or through your browser.

It provides fast and valuable HTTP statistics for system administrators that require a visual server report on the fly.

patchbay.pub is a free web service you can use to implement things like static site hosting, file sharing, cross-platform notifications, webhooks handling, smart home event routing, IoT reporting, job queues, chat systems, bots, etc, all completely serverless and requiring no account creation or authentication. Most implementations need nothing but curl and simple bash snippets.

REDbot is lint for HTTP resources; it tests protocol correctness, cacheability, content negotiation and more. REDbot checks HTTP resources to see how they'll behave, pointing out common problems and suggesting improvements. Although it is not a HTTP conformance tester, it can find a number of HTTP-related issues.

Report URI was founded to take the pain out of monitoring security policies like CSP and HPKP. When you can easily monitor what's happening on your site in real time you react faster and more efficiently, allowing you to rectify issues without your users ever having to tell you.

Interactive cli tool for HTTP inspection

Wuzz command line arguments are similar to cURL's arguments, so it can be used to inspect/modify requests copied from the browser's network inspector with the "copy as cURL" feature.

Polly.JS is a standalone, framework-agnostic JavaScript library that enables recording, replaying, and stubbing HTTP interactions.

Polly taps into native browser APIs to mock requests and responses with little to no configuration while giving you the ability to take full control of each request with a simple, powerful, and intuitive API.

mountebank is the first open source tool to provide cross-platform, multi-protocol test doubles over the wire. Simply point your application under test to mountebank instead of the real dependency, and test like you would with traditional stubs and mocks.

Otoroshi is a modern http reverse proxy with a thin layer of api management written in Scala and developped by the MAIF OSS team. Otoroshi is designed to handle all the calls to and between your microservices without service locator and let you change configuration dynamicaly at runtime.

Fast and safe HTTP for the Rust language.

Motty provides the simpler way to test your client services.
It is a web application which gives you ability to create your own custom responses.
So you can intuitively and easily mock http responses. All you need to do is typing and click!

wrk is a modern HTTP benchmarking tool capable of generating significant load when run on a single multi-core CPU. It combines a multithreaded design with scalable event notification systems such as epoll and kqueue.

An optional LuaJIT script can perform HTTP request generation, response processing, and custom reporting.

tus is a resumable upload protocol, with client and server implementations for all platforms!