Public REST APIs To Use In Tests

• Kong - Scalable, distributed, and plugin oriented API gateway backed by Nginx.
• Tyk API Gateway - Lightweight API gateway with analytics logging, written in Go.
• API Umbrella - API management platform for exposing web services, with web interface and analytics, written in Lua.
• WSO2 API Management - API management tool with lightweight gateway and API lifecycle management, written in Java.
• Express Gateway - Microservices API Gateway built on top of ExpressJS (Node.js).
• KrakenD - Ultra performant API Gateway with middleware. Written in Go.
• Zuplo - OpenAPI-Powered API & MCP Management platform for Security, Deployment, and Documentation. Add auth, rate-limiting, and monetization to your API or MCP Server in minutes, written in TypeScript & Go.
• Lura - Ultra performant API Gateway with middleware. Written in Go.

Generators

• openapi-generator - OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3).

Go Clients

• gopencils - Small and simple package to easily consume REST APIs.
• resty - Simple HTTP and REST client for Go inspired by Ruby rest-client.

JavaScript Clients

• restangular - AngularJS service to handle REST API properly and easily.
• restful.js - JS client for interacting with server-side RESTful resources.
• traverson - A Hypermedia API/HATEOAS Client for Node.js and the Browser
• raml-client-generator - Generates static client libs for js.
• traverson - A Hypermedia API/HATEOAS Client for Node.js and the Browser
• raml-client-generator - Generates static client libs for js.

.NET Clients

• RestSharp - Simple REST and HTTP API client for .NET
• Refit - The automatic type-safe REST library for Xamarin and .NET
• RestEase - Easy-to-use typesafe REST API client library, which is simple and customisable. Heavily inspired by Refit
• Tiny.RestClient - Simpliest Fluent REST client for .NET.
• RestLess - The automatic type-safe-reflectionless REST API client library for .Net Standard.
• Apizr - Refit-based web api client, but resilient (retry, connectivity, cache, auth, log, priority, etc...).

Node.js Clients

• restler - REST client library for node.js.
• unirest for Node.js - Simplified, lightweight HTTP client library.

PHP Clients

• Guzzle - HTTP client and framework for consuming RESTful web services.
• Buzz - Another lightweight HTTP client.
• unirest for PHP - Simplified, lightweight HTTP client library.
• Guzzle - HTTP client and framework for consuming RESTful web services.
• unirest for PHP - Simplified, lightweight HTTP client library.

Ruby Clients

• Net::HTTP - Net::HTTP provides a rich library which can be used to build HTTP user-agents.
• RESTClient - Simple HTTP and REST client for Ruby, inspired by microframework syntax for specifying actions.
• Spyke - Interact with REST services in an ActiveRecord-like manner.
• excon - Usable, fast, simple Ruby HTTP 1.1. It works great as a general HTTP(s) client and is particularly well suited to usage in API clients.
• httparty - Makes HTTP fun again!
• raml-ruby-client-generator - Auto generate API client from a RAML file.

Guidelines

• Adidas REST API Guidelines - Adidas REST API Guidelines define standards and guidelines for building REST APIs at adidas.
• Atlassian REST API design guidelines version 1 - This document provides guidelines to Atlassian developers who are designing REST APIs for Atlassian applications.
• Microsoft REST API Guidelines - The Microsoft REST API Guidelines, as a design principle, encourages application developers to have resources accessible to them via a RESTful HTTP interface.
• Cisco REST API Guide - Guidelines for designing REST APIs at Cisco.
• Haufe API Style Guide - Guidelines created by Haufe-Lexware CTO team.
• Restful API Guidelines by Zalando - Developing Restful APIs: A Comprehensive Set of Guidelines.
• Google Cloud API design guide - Guidelines Google follows when designing Cloud APIs and other Google APIs (REST APIs and gRPC APIs).
• Microsoft REST API Guidelines - The Microsoft REST API Guidelines, as a design principle, encourages application developers to have resources accessible to them via a RESTful HTTP interface.

• Best Practices for Designing a Pragmatic RESTful API
• Richardson Maturity Model - Explained by Martin Fowler, originally presented by Leonard Richardson at the [QCon 2008](https://www.crummy.com/writing/speaking/2008-QCon/act3.html).
• Enterprise Integration Using REST - Discusses the constraints and flexibility that you have with nonpublic APIs, and lessons learned from doing large scale RESTful integration across multiple teams.
• HATEOAS - Clear explanation on what HATEOAS is, and why you should use it.
• How to GET a cup of coffee
• REST API Tutorial - RestApiTutorial.com is dedicated to tracking REST API best practices and making resources available to enable quick reference and self education for the development crafts-person.
• HTTP API design guide extracted from work on the Heroku Platform API
• API-Security-Checklist - Best practices about REST API security
• Architectural Styles and the Design of Network-based Software Architectures - Roy Fielding's dissertation defining REST
• How to design a REST API? - Full guide tackling security, pagination, filtering, versioning, partial answers, CORS, etc.

Public REST APIs To Use In Tests

• Swagger - Documentation/querying web interface for REST APIs.
• API doc - Inline Documentation for RESTful web APIs.
• raml2html - Generates HTML documentation from a RAML file.
• Optic - Maintain an accurate API specification without writing OpenAPI/Swagger. Works with any Stack
• Slate - Beautiful and responsive three-panel API documentation using Middleman.
• Zudoku - Create clean, consistent API docs with Zudoku — open source, extensible, and developer-first
• Sourcey - Open source documentation platform for OpenAPI specs and markdown. Static HTML output.
• Stoplight - Design-first API platform with visual OpenAPI editor, documentation, and mocking.
• Sourcey - Open source documentation platform for OpenAPI specs and markdown. Static HTML output.
• ReDoc - OpenAPI/Swagger-powered three-panel documentation.
• Cortex - Generate interactive API documentation, typed SDKs, and MCP servers from OpenAPI and other API specification formats.

Public REST APIs To Use In Tests

• react-admin - Add a ReactJS admin GUI to any RESTful API.
• ng-admin - Add an AngularJS admin GUI to any RESTful API.
• swagger-codegen - Auto generation of client libraries or server stubs given an OpenAPI specification (formerly known as the Swagger Specification).
• Lumber - Generate the admin interface of your application.
• shadcn-admin-kit - Build internal tools, admin panels, B2B apps, and dashboards on top of any REST API
• Linx - Low-code API platform. Build, debug and host REST APIs

Public REST APIs To Use In Tests

• Amazon API Gateway - Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs at any scale.
• Runscope - Automated API Monitoring & Testing.
• Ping-API - Automated API Monitoring & Testing.
• Apiary - Collaborative design, instant API mock, generated documentation, integrated code samples, debugging and automated testing.
• Beeceptor - An HTTP inspecting, mocking and proxing service. Gives named endpoints for creating mock API endpoints and simulate responses.
• Nango - Native integrations framework to consume REST APIs (open-source).
• BlazeMeter - Continuous testing platform for API performance and load testing at scale.
• Loader.io - Free cloud-based load testing service for APIs.
• Keploy - Open-source API testing and data mocking tool that generates test cases and stubs automatically from real traffic, enabling end-to-end API testing and monitoring.
• Apigee - Apigee is the leading provider of API technology and services for enterprises and developers.
• 3scale - Nginx based API gateway to integrate internal and external API services with 3scale's API Management Platform.
• Assertible - Continuously test and monitor your APIs after deployments and across environments.
• Apitally - Analytics, request logging and monitoring for REST APIs with a focus on simplicity and data privacy.

Directly On Top Of A RMDB

• MySQL HTTP plugin - Simple REST-like / CRUD server for any MySQL database.
• pREST - A fully RESTful API from any existing PostgreSQL database written in Go.
• MySQL HTTP plugin - Simple REST-like / CRUD server for any MySQL database.
• postgrest - Serve a fully RESTful API directly from an existing PostgreSQL database.

Go

• gocrud
• go-json-rest - Thin layer on top of `net/http` that helps building RESTful APIs easily.
• sleepy - RESTful micro-framework written in Go.
• go-relax - Framework of pluggable components to build RESTful API's.
• go-rest - Small and evil REST framework for Go.
• go-restful - A declarative highly readable framework for building restful API's.
• Goat - Minimalistic REST API server in Go.
• Resoursea - REST framework for quickly writing resource based services.
• go-relax - Framework of pluggable components to build RESTful API's.
• restit - Go micro framework to help writing RESTful API integration test.

Haskell

• Rest for Haskell - This package allows you to create REST APIs in Haskell. These APIs can be run in different web frameworks. They can also be used to automatically generate documentation as well as client libraries.

Java

• RestExpress - Netty-based, highly performant, lightweight, container-less, plugin-extensible, framework that is ideal for microservice architectures.
• Vertx-Web - Vert.x-Web is a set of building blocks for building web applications with Vert.x, a toolkit for building reactive applications on the JVM.
• Dropwizard - A framework for developing ops-friendly, high-performance, RESTful web services.

Node.js

• loopback - Powerful Node.js framework for creating APIs and easily connecting to backend data sources.
• Feathers - is a real-time, micro-service web framework that gives you control over your data via RESTful resources, sockets and flexible plug-ins.
• Baucis - Build scalable REST API based on your Mongoose entities.
• node-restify - Framework specifically meant for REST API.
• mers - Express service exposing Mongoose finders as RESTful API.
• flatiron/resourceful - Isomorphic Resource engine for JavaScript.
• Expressa - Express middleware for creating APIs from JSON schemas with a simple admin editor and permissions model.
• rest-hapi - Generate RESTful API based on mongoose models that supports relational data.
• Nestjsx/crud - Generate CRUD controllers and services for RESTful API with NestJS and TypeORM.

PHP

• REST APIs with Symfony2: the Right Way - Complete guide to build a state-of-the-art REST API with Symfony2 framework.
• lakion/Lionframe - Glu between several community libraries to ease API development.
• Microrest - Micro-web application providing a REST API on top of any relational database.
• Negotiation - Content negotiation library.
• Drest - Library for exposing Doctrine entities as REST resource endpoints.
• Restler - Lightweight framework to expose PHP methods as RESTful web API.
• HAL - Hypertext Application Language (HAL) builder library.
• Apigility - API builder built with Zend Framework 2.
• phprest - Specialized REST microframework for PHP.
• Hateoas - PHP library to support implementing representations for HATEOAS REST web services.
• Fusio - Open source API management platform.
• FOSRestBundle - Bundle handling view, routing, error handling, etc. for your REST API.
• stanlemon/rest-bundle - Build a REST API based on Doctrine entities using conventions over configuration.
• BazingaHateoasBundle - Integrate the [Hateoas](https://github.com/willdurand/Hateoas) library into a Symfony2 application.
• Symfony REST Edition - Start with a Symfony2 application with all REST-friendly bundles pre-configured.
• NgAdminGeneratorBundle - Boostrap ng-admin configuration based on `stanlemon/rest-bundle`.
• API Platform - Specialize Symfony edition for the creation of hypermedia REST APIs.
• NelmioApiDocBundle - Generate documentation for your REST API from annotations.
• lakion/Lionframe - Glu between several community libraries to ease API development.
• DunglasApiBundle - Build a REST API which follow Hydra/JSON-LD specification.

PowerShell

• Pode - Pode is an cross-platform, open-source, community-supported web server and REST API framework for PowerShell developers

Python

• Django REST framework - Powerful and flexible toolkit that makes it easy to build Web APIs.
• django-tastypie - Creating delicious APIs for Django apps.
• hug - Lightweight and fast API Framework.
• Ramses - Makes RAML files executable by generating production-ready APIs from them at runtime.
• sandman - Automated REST APIs for existing database-driven systems.
• Flask-Potion - Flask-Potion is a powerful Flask extension for building RESTful JSON APIs. It also provides several Clients for easier access to the API.
• apistar - A smart Web API framework, designed for Python 3.
• Falcon - Falcon is a bare-metal Python web API framework for building high-performance microservices, app backends, and higher-level frameworks.
• django-tastypie - Creating delicious APIs for Django apps.
• FastAPI - FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints. With automatic API documentation using Swagger UI and ReDoc, based on OpenAPI and JSON Schema.
• Zato - Platform for building server-side integrations, automations and API backends in Python.
• Ramses - Makes RAML files executable by generating production-ready APIs from them at runtime.
• Zato - Platform for building server-side integrations, automations and API backends in Python.

Ruby

• Rails - RailsGuides: Using Rails for API-only applications.

Scala

• Chaos - A lightweight framework for writing REST services in Scala.

Guidelines

• JSON API - Standard for building APIs in JSON.
• RAML - Simple and succinct way to describe RESTful API.
• OData - Open protocol to allow the creation and consumption of queryable and interoperable RESTful APIs. Quite complex.
• HAL - Simple format that gives a consistent and easy way to hyperlink between resources in your API.
• JSON-LD - Standard for describing Linked Data and hypermedia relations in JSON (W3C).
• Hydra - Vocabulary for Hypermedia-Driven Web APIs (W3C).
• JSend - Simple specification that lays down some rules for how JSON responses from web servers should be formatted.
• OpenAPI - Formerly known as the Swagger Specification, OpenAPI specifcation is the world’s most popular description format for defining Restful APIs.
• HAL - Simple format that gives a consistent and easy way to hyperlink between resources in your API.
• OpenAPI - Formerly known as the Swagger Specification, OpenAPI specifcation is the world’s most popular description format for defining Restful APIs.

Debugging Proxies

• mitmproxy - Free, open-source interactive HTTPS proxy for debugging API traffic.
• Charles - HTTP proxy/monitor for inspecting API traffic on Windows, Mac, and Linux.
• Fiddler - Web debugging proxy tool by Telerik/Progress.

Mocking

• RequestBin - Inspect and debug webhook requests sent by your clients or third-party APIs.
• MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.
• Mockintosh - A mock server generator that's capable to generate RESTful APIs and communicate with the message queues to mimick asynchronous tasks.
• FakeRest - Patch XMLHttpRequest to fake a REST API client-side.
• json-server - Serve a REST API from fixture files using quick prototyping.
• Request Baskets - Service to collect HTTP requests and inspect them via RESTful API or web UI.
• DuckRails - Mock quickly & dynamically API endpoints.
• httpbin - HTTP request and response service - a/k/a Swiss Army Knife for HTTP.
• Mockoon - Easily create mock APIs locally. No remote deployment, no account required, open source.

Public REST APIs To Use In Tests

• Deck of Cards API - Open API for simulating a deck of cards.
• ProgrammableWeb - The world's largest API repository.
• Marvel Comics API - Query characters, stories, events about Marvel superheroes.
• JSON Placeholder - Free online REST service that you can use whenever you need some fake data.
• The Cat API - Public API for Cats Images, Facts and Jokes.
• Public APIS - Explore The Largest API Directory In The Galaxy.
• APIs.guru - Wikipedia for Web APIs, each API has OpenAPI/Swagger description.
• Mockae - Fake REST API powered by Lua.
• Public APIs - The world's largest directory of public APIs.

Querying

• HttpMaster - GUI tool for testing REST APIs and services. Windows OS only.
• ExtendsClass - Make HTTP requests with a simple web-based HTTP client.
• TestMace - Cross-platform simple but powerful IDE for API automation testing.
• resty - Little command line REST client that you can use in pipelines (bash or zsh).
• Http-console - Command line interface for HTTP that let you *speak HTTP like a local*
• rest-assured - Java DSL for easy testing of REST services.
• Milkman - Extensible cross-platform request/response workbench, not only for http calls.
• Schemathesis - Property-based testing tool for web applications built with Open API and GraphQL specifications.
• Step CI - Open-source framework for API Quality Assurance, which tests REST, GraphQL and gRPC automated and from Open API spec.
• RestQA - A REST API testing Framework based on BDD / Gherkin to manage microservice local testing.
• httpie - Command line HTTP client, far more dev-friendly than `curl`.
• HTTP Prompt - HTTP Prompt is an interactive command-line HTTP client featuring autocomplete and syntax highlighting, built on HTTPie and prompt_toolkit.
• Postman - Cross-platform API development and testing platform.
• SoapUI - Cross-platform API testing tool for REST and SOAP APIs.
• RapidAPI - Full-featured HTTP client for macOS.
• Insomnia - Cross-platform HTTP and GraphQL Client
• TestMace - Cross-platform simple but powerful IDE for API automation testing.