HTTP API Development Tools

This is a collection of useful resources for building RESTful HTTP+JSON APIs. There are a lot of good tools and entire ecosystems out there! It can be overwhelming not knowing what options are available, so you can use this as a reference starting point.

API Specification Languages

API Specification Tools

Swagger Inspector: Test and auto-generate OpenAPI documentation for any API.
Swagger Editor: An editor for designing Swagger specifications.
Swagger Tools and Integrations: A list of libraries and frameworks serving the Swagger ecosystem.
OpenAPI extension for VS Code: Visual Studio Code (VS Code) extension that provides support for the OpenAPI Specification.
OpenAPI plugin for JetBrains IDEs: Jetbrains plugin that provides support for the OpenAPI Specification.
Dredd: Validate API documentation written in API Blueprint against its backend implementation.
API Spec Converter: Convert between different API spec formats.
Apimatic: Supports API description formats including Swagger, OAI format, RAML, API Blueprint, IO Docs, WADL, Postman Collections and HAR 1.4 and more
OpenAPI Definition Designer: Free visual OpenAPI3 definition creation and editing tool.
Stoplight Studio: Create, prototype, and share OpenAPI descriptions and JSON Schemas using a visual editor.
Spectral: Define rulesets to lint YAML or JSON, including OpenAPI 2.x, 3.x and AsyncAPI

API Specifications

API Commons: A repository of language-agnostic API specifications / Data Models.
APIS.guru: Directory of API specs in OpenAPI(aka Swagger) 2.0 format.
AnyAPI: Documentation and Test Consoles for Public APIs.

API Frameworks

Ruby

rails-api: Rails for API only applications.
pliny: Opinionated template Sinatra app for writing APIs in Ruby.
grape: An opinionated micro-framework for creating REST-like APIs in Ruby.
ActiveModel::Serializer: Brings convention over configuration to your JSON generation.
rabl: Generate JSON and XML from any ruby object.
jbuilder: Create JSON structures via a Builder-style DSL.
roar: Parse and render REST API documents using representers.

Python

Django REST framework: Toolkit that makes it easy to build Web APIs.
Tastypie: Webservice API framework for Django.
restless: A lightweight REST miniframework for Python.
flask-restful: Simple framework for creating REST APIs.
Falcon: Falcon is a low-level, high-performance Python framework for building HTTP APIs, app backends, and higher-level frameworks.
Connexion: Swagger/OpenAPI First framework for Python on top of Flask with automatic endpoint validation and OAuth2 support
apistar: A smart Web API framework, designed for Python3.
sanic: Sanic is a Flask-like Python 3.5+ web server that’s written to go fast.
hug: hug aims to make developing Python driven APIs as simple as possible, but no simpler.
FastAPI: FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.

Javascript

hapi.js: Web and services application framework for Node.js.
Restify: Node.js REST framework specifically meant for web service APIs.
Express: Fast, unopinionated, minimalist web framework for Node.js.
sailsjs: Realtime MVC Framework for Node.js.
Actionhero: Multi-transport Node.js API server with integrated cluster capabilities and delayed tasks.
Baucis: To build
Koa: Next generation web framework for Node.js
Loopback: Node.js framework for creating APIs and easily connecting to backend data sources.
Seneca: A microservices toolkit for Node.js.
Feathers: Build RESTful and real-time APIs through Socket.io or Primus.
Deployd: Deployd is the simplest way to build realtime APIs for web and mobile apps
Nest: A modern node.js framework for efficient and scalable web applications built on top of TypeScript

Go-Json-Rest: Thin layer on top of net/http that helps building RESTful APIs easily
gocrud: Go library to simplify creating, updating and deleting arbitrary depth structured data — to make building REST services fast and easy.
sleepy: RESTful micro-framework written in Go.
restit: Go micro framework to help writing RESTful API integration test.
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.
Zerver: Zerver is a expressive, modular, feature completed RESTful framework.
Fiber: ⚡Fiber is an Express inspired web framework written in Go with ☕ .

Scala

Colossus: I/O and microservice library for Scala.
Finatra: Fast, testable, Scala HTTP services built on Twitter-Server and Finagle.
Play: The high velocity web framework for Java and Scala.
Scalatra: Simple, accessible and free web micro-framework.
Skinny Micro: Micro-web framework to build servlet applications in Scala.
Spray: Open-source toolkit for building REST/HTTP-based integration layers on top of Scala and Akka.
Akka HTTP: The Akka HTTP modules implement a full server- and client-side HTTP stack on top of akka-actor and akka-stream.
Swagger Akka HTTP: Swagger-Akka-Http brings Swagger support for Akka-Http Apis.

Java

Rest.li: REST framework using type-safe bindings and asynchronous, non-blocking IO.
Dropwizard: Framework for developing ops-friendly, high-performance, RESTful web services.
Jersey: RESTful web services in Java.
Spring Boot: RESTful Web Service using Spring, high-performance and little configuration needed.
Metamug Mason: Create REST APIs with JSP tags and SQL. Edit and hot deploy REST resources on the server.

Haskell

Scotty: Micro web framework inspired by Ruby’s Sinatra, using WAI and Warp.
Spock: Another Haskell web framework for rapid development.
Servant: A Type-Level Web DSL.
Yesod: The Haskell RESTful web framework.

Elixir

Phoenix: Framework for building HTML5 apps, API backends and distributed systems.
Plug: A specification and conveniences for composable modules between web applications.

Erlang

Cowboy: Small, fast, modular HTTP server written in Erlang.
Gen Microservice: This library solves the problem of implementing microservices with Erlang.
Mochiweb: Erlang library for building lightweight HTTP servers.

Postgres

PostgREST: Serve a RESTful API from any existing PostgreSQL database.
pREST: pREST is a way to serve a RESTful API from any databases written in Go.

MySQL

xmysql: Generate REST APIs for any MySQL Database.

PHP

API Platform: API framework on top of Symfony with JSON-LD, Schema.org and Hydra support
Dingo API: A RESTful API package for the Laravel and Lumen frameworks
Fractal: Fractal provides a presentation and transformation layer for complex data output, the like found in RESTful APIs, and works really well with JSON
Yii2 Framework: Provides a whole set of tools to simplify the task of implementing RESTful Web Service APIs

Plumber: API Framework to build APIs for simple R Functions

ASP.NET Web APIs: Build secure REST APIs on any platform with C#

Miscellaneous

Dream Factory: Turn any database into an API platform.

API Client Development Tools

General

Swagger CodeGen: Generate client libraries automatically from a Swagger-compliant server.
AutoRest: Generate client libraries for RESTful web services
OpenAPI Generator: A community fork of Swagger Codegen to automatically generate API clients, server stubs and documentation for REST APIs given an OpenAPI/Swagger spec.

Ruby

Net::HTTP: An HTTP client API for Ruby.
faraday: Simple, but flexible HTTP client library, with support for multiple backends.
rest-client: Simple HTTP and REST client for Ruby
heroics: Ruby HTTP client for APIs represented with JSON schema.
blanket: A Ruby API wrapper.
nestful: Ruby HTTP/REST client.

Java

Retrofit: A type-safe HTTP client for Android and Java.

Javascript

Restangular: Restangular is an AngularJS service that simplifies common GET, POST, DELETE, and UPDATE requests with a minimum of client code

.NET

Refit: The automatic type-safe REST library for .NET Core, Xamarin and .NET
WebAnchor: Web Anchor provides type-safe, testable and flexible access to web resources.

API Documentation

ReDoc: OpenAPI/Swagger-generated API Reference Documentation.
Swagger UI: Dynamically generate documentation from a Swagger-compliant API.
Slate: Static site generated documentation for your API.
prmd: JSON Schema tooling: scaffold, verify, and generate documentation from JSON Schema documents.
Aglio: An API Blueprint renderer with theme support that outputs static HTML.
Apiary: Collaborative design, instant API mock, generated documentation, integrated code samples, debugging and automated testing.
Readme: API Documentation Hosting.
API Docs: Hosted public API documentation for OAS (Swagger) and RAML specs.
Docbox: REST API documentation generator, using Markdown.
widdershins: REST API documentation generator from OpenAPI 3.0 / Swagger 2.0 / AsyncAPI 1.x / Semoasa 0.1.0 definition
Elements: Web Components-based API documentation for OpenAPI 3.x/2.x

API Clients

Open Source

Hoppscotch: API client for REST, GraphQL, Websocket, SSE, Socket.IO and MQTT

Hosted

JSON Generator: Generate and host mock JSON data.

Desktop

Postman: Desktop API testing tool.
Firecamp: API Studio for WebSocket, Rest API and GraphQL.
HTTPie: Command line HTTP client.
Paw: REST client for Mac.
Insomnia: REST API client for Mac, Windows, and Linux.

API Debugging and Mocking

Hosted

Beeceptor: An HTTP-proxy for rest APIs – inspect and build mock APIs.
MockBin: Generate mock HTTP endpoints.
httpbin: Templated responses for testing various scenarios for HTTP requests.
Prism: a set of packages for API mocking and contract testing with OpenAPI v2 (formerly known as Swagger) and OpenAPI v3.x, including mock servers and a validation proxy.
MockingCloud: Generate full mock REST APIs with just OpenAPI yaml/json spec files.

Desktop

Postman: Desktop API client and mocking tool.
Json-Server Full fake REST API with zero coding.
Mockoon: Desktop API mocking tool.

API Design Guides

API Publishing

Mashape: API Marketplace.

API Gateways

AWS API Gateway: Traffic management, authorization and access control, monitoring, and API version management.
Ambassador API Gateway: Ambassador is a specialized control plane that translates Kubernetes annotations to Envoy configuration. All traffic is directly handled by the high-performance Envoy Proxy.
APIGrove: API manager built in Java on top of Fuse ESB.
Apigee127: nodejs based API Gateway
Pushpin: Proxy for both request/response or streaming (long poll) of responses
Strongloop: nodejs based API Gateway
Fusio: PHP based open source API management platform
Camel: Empowers you to define routing and mediation rules in a variety of domain-specific languages, including a Java-based fluent API, Spring or Blueprint XML configuration files, and a Scala DSL.
HAProxy: Reliable, high Performance TCP/HTTP load balancer.
OpenResty: Fast web application server built on top of Nginx.
Tengine: A distribution of Nginx with some advanced features.
Tyk: Open-source, fast and scalable API gateway, portal and API management platform.
Vulcand: Programmatic load balancer backed by Etcd.
Zuul: An edge service that provides dynamic routing, monitoring, resiliency, security, and more.
Kong: An open-source management layer for APIs, delivering high performance and reliability.
Janus: A lightweight API Gateway written in Go by Hello Fresh.
fabio: A fast, modern, zero-conf load balancing HTTP(S) router for deploying microservices managed by consul by eBay.
Traefik: Træfik (pronounced like traffic) is a modern HTTP reverse proxy and load balancer written in Go.
Oathkeeper: OIdentity & Access Proxy (IAP) that authorizes HTTP requests based on sets of rules. Integrates with ORY Hydra.

API Security

Online OpenAPI/Swagger File Security Audit: Free online static analysis of API contract files. Upload the file and get the report.
API Security checklist: Checklist of the most important security countermeasures when designing, testing, and releasing your API.
Ory Hydra: OAuth2 server with OpenID Connect written in Go.

API Web Scanners

Cherrybomb: Stop half-done API specifications! Cherrybomb is a CLI tool that helps you avoid undefined user behaviour by validating your API specifications.

API Monitoring

Runscope: API Performance Monitoring.
Ping-API: Automated API Testing.

API Testing

Assertible: Continuously test and monitor your APIs after deployments and across environments.
Pyresttest: YAML based REST testing and API microbenchmarking tool
OWASP Zaproxy: A tool to test your API for known security vulnerabilities, with a great CI integration.

API Developer Portal

Tyk: API Developer Portal on top of API gateway, make your API gateway easier to be used by developers.
APIMATIC: Instantly build an API Portal with SDKs, Live Code Samples, Test Cases, API Transformation and language specific Docs & Reference – tailored for your API.

HTTP API Development Tools