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.

Contributions are most welcome. Categories are also open to suggestions!

• API Specification Languages
• API Specification Tools
• API Frameworks
• API Client Library Tools
• API Documentation
• API Testing
• API Design Guides
• API Publishing
• API Gateways
• API Monitoring
• JSON Format Standards
• Learning Resources
• References

• API Blueprint
• JSON Schema
• RAML
• Swagger

• Swagger Editor: An editor for designing Swagger specifications.
• API Studio. Write, mock, and share your Swagger specifications online.
• Dredd: Validate API documentation written in API Blueprint against its backend implementation.
• APITransformer: Transform API Descriptions from/to various formats e.g., Swagger, API Blueprint, RAML, WADL, Google Discovery, I/O Docs.

• 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.

• 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.

• 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

• Go-Json-Rest

• 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.

• Scotty - Micro web framework inspired by Ruby's Sinatra, using WAI and Warp.
• Yesod - The Haskell RESTful web framework.

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

• 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.

• PostgREST: Serve a RESTful API from any existing PostgreSQL database.

• API Platform: API framework on top of Symfony with JSON-LD, Schema.org and Hydra support

• Swagger CodeGen: Generate client libraries automatically from a Swagger-compliant server.

• heroics: Ruby HTTP client for APIs represented with JSON schema.
• blanket: A Ruby API wrapper.
• nestful: Ruby HTTP/REST client.

• 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.
• Embed curl: Embeddable curl commands on the web.
• Gelato: Create developer portals for your API.

• Postman: Desktop API testing tool.
• Paw: REST client for Mac.
• Insomnia REST Client: REST client Chrome app.
• MockBin: Generate mock HTTP endpoints.
• JSON Generator: Generate and host mock JSON data.
• RequestBin: Inspect and debug webhook POST requests.
• Hurl.it: Web-based HTTP client.

• PayPal API Style Guide
• Heroku Platform HTTP API Design Guide
• Haufe API Style Guide

• Mashape: API Marketplace.

• AWS API Gateway. Traffic management, authorization and access control, monitoring, and API version management.
• API Umbrella: Proxy that sits in front of your APIs.
• APIAxle: Proxy that sits in front of your APIs.
• APIGrove: API manager built in Java on top of Fuse ESB.
• APIUmbrella: API management platform
• 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.

• Runscope: API Performance Monitoring.
• Galileo: API Monitoring Platform.
• Ping-API: Automated API Testing.

• HAL
• JSONAPI

• Choosing an HTTP Status Code
• REST in Practice
• Roy Fielding's dissertation on REST
• Best Practices for Designing a Pragmatic RESTful API
• How to Design a REST API

• HTTP Status Codes Reference

Pull Requests are most welcome!

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