OpenAPI.Tools

Tool Types

We've organised everything into categories so you can jump to the section you're interested in.

Converters: Various tools to convert to and from OpenAPI and other API description formats.
Data Validators: Check to see if API requests and responses are lining up with the API description.
Description Validators: Check your API description to see if it is valid OpenAPI.
Documentation: Render API Description as HTML (or maybe a PDF) so slightly less technical people can figure out how to work with the API.
DSL: Writing YAML by hand is no fun, and maybe you don't want a GUI, so use a Domain Specific Language to write OpenAPI in your language of choice.
GUI Editors: Visual editors help you design APIs without needing to memorize the entire OpenAPI specification.
Learning: Tools that make it easy to learn an OpenAPI description by inspecting real traffic.
Miscellaneous: Anything else that does stuff with OpenAPI but hasn't quite got enough to warrant its own category.
Mock Servers: Fake servers that take description document as input, then route incoming HTTP requests to example responses or dynamically generates examples.
Parsers: Loads and read OpenAPI descriptions, so you can work with them programmatically.
SDK Generators: Generate code to give to consumers, to help them avoid interacting at a HTTP level.
Security: By poking around your OpenAPI description, some tools can look out for attack vectors you might not have noticed.
Server Implementations: Easily create and implement resources and routes for your APIs.
Testing: Quickly execute API request and validate responses on the fly through command line or GUI interfaces.
Text Editors: Text editors give you visual feedback whilst you write OpenAPI, so you can see what docs might look like.

Converters

Various tools to convert to and from OpenAPI and other API description formats.

Name	Language	v2	v3
Apimatic Transformer - Transform API Descriptions to and from RAML, API Blueprint, OAI v2/v3, WSDL, etc.	SaaS	✅	✅
avantation - Generate OpenAPI 3.x specification from HAR.	TypeScript	❌	✅
go-swagger - Unmaintained v2.0 only project seeking new maintainer, or probably a fork. Parser, validator, generates descriptions from code, or code from descriptions!	Go	✅	❌
Google Gnostic - Compile OpenAPI descriptions into equivalent Protocol Buffer representations	Go	✅	✅
JSON Schema to OpenAPI Schema - Due to the OpenAPI v3.0 and JSON Schema discrepancy, you can use this JS library to convert JSON Schema objects to OpenAPI Schema.	JavaScript	❌	✅
laravel-openapi - Generate OpenAPI 3 specification for Laravel Applications.	PHP	❌	✅
OAS RAML Converter - Converts between OpenAPI and RAML API specifications	Node.js	✅	✅
OData OpenAPI - OData 4.0 to OpenAPI v3.0 converter	XSLT	✅	✅
OData.OpenAPI - Convert an Edm (Entity Data Model) to OpenAPI 3.0	.NET	❌	✅
odata2openapi - OData 4.0 to OpenAPI v2.0 converter	Node.js	✅	❌
OpenAPI Filter - Filter internal components from OpenAPI Descriptions	Node.js	✅	✅
OpenAPI Schema to JSON Schema - Due to the OpenAPI v3.0 and JSON Schema discrepancy, you can use this JS library to convert OpenAPI Schema objects to proper JSON Schema.	JavaScript	❌	✅
pyswagger - Client & converter in Python, which is type-safe, dynamic, spec-compliant.	Python	✅	👷
swagger2openapi - Upgrade files from OpenAPI v2.0 to v3.0, bundling into one mega file or respecting $refs. Part of oas-kit.	Node.js / CLI	✅	✅

Data Validators

Check to see if API requests and responses are lining up with the API description.

Name	Language	v2	v3
committee - Validation middleware for Rack server. This gem validates request and response using an OpenAPI Description. And convert parameter string to specific Ruby object (e.g. convert datetime string to DateTime class).	Ruby	✅	✅
express-ajv-swagger-validation - Express middleware which validates request body, headers, path parameters and query parameters according to an OpenAPI Description	Node.js	✅	✅
express-openapi-validator - 🦋 Auto-validate API requests and responses in ExpressJS.	JavaScript	❌	✅
kin-openapi - A Go library for handling OpenAPI 3.0 specifications	Go	❌	✅
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅
OpenAPI Enforcer - Validate your OpenAPI document, serialize, deserialize, and validate incoming requests and outgoing responses, and simplify response building. You can even produce mock data.	Node.js	✅	✅
openapi-psr7-validator - Using a PHP framework that supports PSR-7? Get free validation without writing a bunch of code, by registering this middleware and pointing it at your API description document.	PHP	❌	✅
openapi-spring-webflux-validator - 🌱 A friendly kotlin library to validate API endpoints using an OpenAPI 3.0 or OpenAPI 2.0 specification	Java/Kotlin	✅	✅
openapi4j - Parse Description Document, validate api requests and responses using OpenAPI 3.x.	Java	❌	✅
openVALIDATION - Allows complex validation rules to be specified in openAPI spec files using natural language.	Java	❌	✅

Documentation

Render API Description as HTML (or maybe a PDF) so slightly less technical people can figure out how to work with the API.

Name	Language	v2	v3
APIMatic Developer Experience Portal - Customizable developer portals packed with language specific documentation, client libraries, code samples, an API console and much more.	SaaS	✅	✅
Apitive Studio - A platform for Digital Product Managers and API Consultants to design REST APIs with in-built mock and documentation.	Angular 7.0, Java / Saas	✅	✅
APITree - HUB for managing and sharing APIs. Converts OpenAPI v2 / v3 files into beautiful API documentations.	SaaS	✅	✅
Bump - Bump generates elegant documentations and changelogs from your OpenAPI specifications. Git diff, for your API.	SaaS	✅	✅
Kong Enterprise Edition - Highly customizable developer portal with developer onboarding, integrated with the Kong API Gateway	Lua	✅	✅
LucyBot DocGen - Generate a customizable website, with API documentation, console, and interactive workflows, from an OpenAPI spec	JavaScript	✅	✅
MrinDoc - OpenAPI description document viewer.	Vue.JS	✅	✅
Nexmo OAS Renderer - Ruby OpenAPI docs rendering, use standalone or add to your Rails app	Ruby	❌	✅
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅
oas3-api-snippet-enricher - Enrich your existing description documents with generated code samples	JavaScript	❌	✅
openapi-viewer - Browse and test a REST API described with the OpenAPI 3.0 Specification	Vue.js	❌	✅
RapiDoc - Custom Element to view OpenAPI descriptions.	Custom Element	✅	✅
RapiPdf - Custom Element to generate PDF from OpenAPI descriptions.	Custom Element	✅	✅
ReadMe - Build beautiful, personalized, interactive developer hubs	SaaS	✅	✅
ReDoc - OpenAPI-generated API Reference Documentation	React.js	✅	✅
Stoplight Docs - Create beautiful, customizable, interactive API documentation generated from OpenAPI, integrated with Stoplight Studio	SaaS	✅	✅
widdershins - Generate Slate/Shins markdown from OpenAPI 2.0/3.0.x	Node.js	✅	✅

DSL

Writing YAML by hand is no fun, and maybe you don't want a GUI, so use a Domain Specific Language to write OpenAPI in your language of choice.

Name	Language	v2	v3
BOATS - BOATS allows for larger teams to contribute to multi-file OpenAPI defintions by writing Nunjucks tpl syntax in yaml with a few important helpers to ensure stricter consistency, eg operationId: <$ uniqueOpId() $>.	Node.js	✅	✅
Spot - A concise, developer-friendly way to describe your API contract.	TypeScript	✅	✅
Supermodel - Model your data using JSON Schema, refer and remix the models freely, convert to various formats including OAS v2/v3.	SaaS	✅	✅

Text Editors

Text editors give you visual feedback whilst you write OpenAPI, so you can see what docs might look like.

Name	Language	v2	v3
Atom/linter-swagger - This plugin for Atom Linter will lint OpenAPI, both JSON and YAML using swagger-parser node package.	JavaScript	✅	✅
KaiZen-OpenAPI-Editor - Full-featured Eclipse editor for OpenAPI, also available on Eclipse Marketplace.	Java	✅	✅
Senya Editor - JetBrains IDE plugin to show Swagger UI as a preview, for visual feedback as you edit.	Java	✅	✅
Swagger Editor - Design, describe, and document your API on the first open source editor fully dedicated to OpenAPI-based APIs.	Node.js	✅	✅
SwaggerHub - API design and documentation platform to improve collaboration, standardize development workflow and centralize their API discovery and consumption.	SaaS/On-Premise NodeJS	✅	✅
VSCode OpenAPI - OpenAPI extension for Visual Studio Code - new file templates, navigation, intellisense, code snippets.	Any	✅	✅
VSCode/openapi-lint - OpenAPI 2.0/3.0.x intellisense, validator and linter for Visual Studio Code	Node.js	✅	✅

GUI Editors

Visual editors help you design APIs without needing to memorize the entire OpenAPI specification.

Name	Language	v2	v3
Apicurio Studio - Web-Based Open Source API Design via the OpenAPI specification.	Angular 7.0, Java / Saas	✅	✅
Apitive Studio - A platform for Digital Product Managers and API Consultants to design REST APIs with in-built mock and documentation.	Angular 7.0, Java / Saas	✅	✅
Flotiq - headless CMS with OpenAPI support - Visually define your Content Types, Flotiq automatically generates your own OpenAPI v3 compatible endpoints, SDKs and Postman collections.		❌	✅
Hackolade - A visual editor for OpenAPI v2/v3, from the pioneer in data modeling for NoSQL databases.	ReactJS	✅	✅
RepreZen API Studio - RepreZen API Studio is an integrated workbench that brings API-first design into focus for your whole team, harmonizes your API designs, and generates APIs that click into client apps.	Java	✅	✅
Stoplight Studio - Stoplight Studio is a GUI/text editor with linting and mocking built right in. It can run on the desktop with local files, and in the browser powered by your existing GitHub, GitLab, or BitBucket repos.	Desktop / SaaS	✅	✅

Learning

Tools that make it easy to learn an OpenAPI description by inspecting real traffic.

Name	Language	v2	v3
Meeshkan - Mock HTTP APIs through a combination of API definitions, recorded traffic and code. Used for sandboxes, as well as automated and exploratory testing.	Python	❌	✅
Optic - A proxy server that watches an API and helps you build an OpenAPI description interactively.	cli	❌	✅
Swagger Inspector - Run mock requests in a webapp and Swagger Inspector infers your OpenAPI description.	SaaS	✅	✅

Mock Servers

Fake servers that take description document as input, then route incoming HTTP requests to example responses or dynamically generates examples.

Name	Language	v2	v3
API Sprout - Lightweight, blazing fast, cross-platform OpenAPI 3 mock server with validation	cli / Docker	❌	✅
Apitive Studio - A platform for Digital Product Managers and API Consultants to design REST APIs with in-built mock and documentation.	Angular 7.0, Java / Saas	✅	✅
Connexion - OpenAPI First framework for Python on top of Flask with automatic endpoint validation & OAuth2 support	Python	✅	✅
Fakeit - Create mock server from OpenAPI 3 specification with random response generation and request validation.	cli / Docker	❌	✅
Falcon Heavy - The framework for building app backends and microservices via the API design-first workflow.	Python	❌	✅
Meeshkan - Mock HTTP APIs through a combination of API definitions, recorded traffic and code. Used for sandboxes, as well as automated and exploratory testing.	Python	❌	✅
Microcks - Mocking and testing platform for API and microservices. Turn your OAI contract examples into ready to use mocks. Use examples to test and validate implementations according schema elements.	Self-hosted / SaaS	✅	✅
MockLab - SaaS platform to upload your spec to create a mock server	SaaS	✅	✅
OpenAPI Mocker - Standalone nodejs based OpenAPI 3 mock server, docker-friendly with request validation and autoreload.	nodejs	❌	✅
Prism - Turn any OAI file into an API server with mocking, transformations, validations, and more.	cli	✅	✅
Sandbox - SaaS, self-hosted, or CLI tool for turning OpenAPI (and other) descriptions into a mock server, where you can modify behaviour, simulate downtime, and any other nonsense you can think of thanks to a built-in code editor!	SaaS / Java	✅	✅
Unmock - API integration testing library that intercepts outgoing requests and serves back mock data based on the OpenAPI descriptions.	Node.js	❌	✅
yii2-app-api - Generate Server side API code with routing, models, data validation and database schema from an OpenAPI description. Based on Yii Framework.	PHP	❌	✅

Description Validators

Check your API description to see if it is valid OpenAPI.

Name	Language	v2	v3
BigstickCarpet/swagger-cli - Simple validation for OpenAPI files, supporting JSON/YAML and v2/v3 description documents.	Node.js / CLI	✅	✅
express-openapi-validator - 🦋 Auto-validate API requests and responses in ExpressJS.	JavaScript	❌	✅
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅
OpenAPI Enforcer - Validate your OpenAPI document, serialize, deserialize, and validate incoming requests and outgoing responses, and simplify response building. You can even produce mock data.	Node.js	✅	✅
OpenAPI Style Validator - A customizable style validator to make sure your OpenAPI description follows your organization's standards.	Java, CLI	✅	✅
openapi-spec-validator - OpenAPI Description validator	Python	✅	✅
openapi-spring-webflux-validator - 🌱 A friendly kotlin library to validate API endpoints using an OpenAPI 3.0 or OpenAPI 2.0 specification	Java/Kotlin	✅	✅
openVALIDATION - Allows complex validation rules to be specified in openAPI spec files using natural language.	Java	❌	✅
php-openapi - A PHP library for manipulating and validating OpenAPI 3.0 Descriptions	PHP	❌	✅
Spectral - A flexible JSON/YAML object linter with portable "rulesets" and custom functions.	CLI & TypeScript/JavaScript	✅	✅

Security

By poking around your OpenAPI description, some tools can look out for attack vectors you might not have noticed.

Name	Language	v2	v3
42crunch - A unique set of integrated API security tools which allow discovery, remediation of OpenAPI vulnerabilities and runtime protection against API attacks.	SaaS	✅	✅
API Contract Security Audit - Upload OpenAPI file, get detailed report with located vulnerabilities, possible attack scenarios, ways to remediate.	SaaS	✅	❌
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅

SDK Generators

Generate code to give to consumers, to help them avoid interacting at a HTTP level.

Name	Language	v2	v3
APIMatic CodeGen - Bring in your API description (OAI v2/v3, RAML, API Blueprint, WSDL, etc.) to generate fully functional SDKs in over 10 languages.	SaaS	✅	✅
Flotiq - headless CMS with OpenAPI support - Visually define your Content Types, Flotiq automatically generates your own OpenAPI v3 compatible endpoints, SDKs and Postman collections.		❌	✅
go-swagger - Unmaintained v2.0 only project seeking new maintainer, or probably a fork. Parser, validator, generates descriptions from code, or code from descriptions!	Go	✅	❌
guardrail - Principled code generation from OpenAPI descriptions	Scala, Java, ...	✅	✅
janephp/open-api - Generate a PHP Client API (PSR-7 compatible) given a OpenAPI specification.	PHP	✅	✅
oazapfts! - Generate TypeScript clients from a given OpenAPI description document.	TypeScript	✅	✅
OpenAPI Generator - A template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI Description (community-driven fork of swagger-codegen)	Java	✅	✅
restful-react - Generate React hooks with appropriate type-signatures from OpenAPI descriptions	React (Typescript)	✅	✅
Unchase.OpenAPI.Connectedservice - Visual Studio extension to generate C# (TypeScript) HttpClient (or C# Controllers) code for OpenAPI web service with NSwag.	.NET	✅	✅

Server Implementations

Easily create and implement resources and routes for your APIs.

Name	Language	v2	v3
@eropple/nestjs-openapi3 - Integrates tightly with a NestJS application to infers complex descriptions and expresses them in its generated OpenAPI document. It then presents that document via ReDoc, and validates inputs for conformance to spec.	Node.js	❌	✅
@nestjs/swagger - Official OpenAPI (Swagger) module for NestJS. Use decorators to define OpenAPI endpoint documentation, parameters and return types. Integrates tightly with a NestJS application. Ships with Swagger UI and serves OpenAPI v3 spec.	TypeScript	❌	✅
@smartrecruiters/openapi-first - Initializes your API express application with description in OpenAPI 3.0 format using provided middlewares (parsers, validators, controller, defaults setting) or custom ones	Node.js	❌	✅
API Platform - REST and GraphQL framework to build modern API-driven projects	PHP	✅	✅
BaucisJS + baucis-openapi3 - Create REST resources with persistence on MongoDB and expose OpenAPI v.3 contracts	JavaScript	❌	✅
BaucisJS + baucis-swagger2 - Create REST resources with persistence on MongoDB and expose OpenAPI v.2 contracts	JavaScript	✅	❌
Falcon Heavy - The framework for building app backends and microservices via the API design-first workflow.	Python	❌	✅
Fusio - Open source API management platform	PHP	❌	✅
MicroTS - Take an OpenAPI description and generate TypeScript projects via Docker.	Node.js	✅	✅
Mojolicious::Plugin::OpenApi - Mojolicious::Plugin::OpenAPI is a plugin for Mojolicious framework that add routes and input/output validation to your Mojolicious application based on OpenAPI description documents.'	Perl	✅	✅
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅
OpenAPI Enforcer Middleware - An express middleware that makes it easy to write web services that follow an OpenAPI specification by leveraging the tools provided in the openapi-enforcer package.	Node.js	✅	✅
openapi-backend - Build, Validate, Route, and Mock using OpenAPI specification. Framework-agnostic	Node.js	❌	✅
tsoa - Creates OpenAPI docs and provides free runtime validation for your Koa, Express, Hapi (and more) services	TypeScript	✅	✅
Vert.x Web Api Contract - Create API endpoints with Vert.x 3 and OpenAPI 3 with automatic requests validation	Java, Kotlin, JavaScript, Groovy, Ruby, Ceylon & Scala	❌	✅
Vert.x Web API Service - Create API service proxies using event bus with request/response validation	Java	❌	✅
yii2-app-api - Generate Server side API code with routing, models, data validation and database schema from an OpenAPI description. Based on Yii Framework.	PHP	❌	✅

Miscellaneous

Anything else that does stuff with OpenAPI but hasn't quite got enough to warrant its own category.

Name	Language	v2	v3
$ oas (CLI) - Generate OAS files from code comments and easily host them ($ npm install oas -g)	JavaScript	✅	✅
express-openapi-validator - 🦋 Auto-validate API requests and responses in ExpressJS.	JavaScript	❌	✅
Flotiq - headless CMS with OpenAPI support - Visually define your Content Types, Flotiq automatically generates your own OpenAPI v3 compatible endpoints, SDKs and Postman collections.		❌	✅
laravel-openapi - Generate OpenAPI 3 specification for Laravel Applications.	PHP	❌	✅
OpenAPI Server Code Generator (oapi-codegen) - Generate a web service using the [Echo](https://github.com/labstack/echo) framework from an OpenAPI v3 specification	Go	❌	✅
openapi-cli-tool - Can list up defined API paths and bundle multi-file into one. Supports multiple file extensions.	Python	❌	✅
openapi-diff - Utility for comparing two OpenAPI specifications.	Java	❌	✅
openapi-spring-webflux-validator - 🌱 A friendly kotlin library to validate API endpoints using an OpenAPI 3.0 or OpenAPI 2.0 specification	Java/Kotlin	✅	✅
openVALIDATION - Allows complex validation rules to be specified in openAPI spec files using natural language.	Java	❌	✅

Parsers

Loads and read OpenAPI descriptions, so you can work with them programmatically.

Name	Language	v2	v3
BigstickCarpet/swagger-parser - Swagger/OpenAPI 2.0 and 3.0 parser and validator. Can also bundle multiple files into one via `$ref`.	Node.js	✅	✅
KaiZen OpenAPI Parser - High-performance Parser, Validator, and Java Object Model for OpenAPI 3.x	Java	❌	✅
kin-openapi - A Go library for handling OpenAPI 3.0 specifications	Go	❌	✅
Microsoft/OpenAPI.NET - C# based parser with OpenAPI Description validation and migration support from V2	.NET	✅	✅
oas-tools - NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over express servers, including security validations	Node.js	❌	✅
oas_parser - A Ruby parser for OpenAPI 3.0+ descriptions.	Ruby	❌	✅
Object Oriented OpenAPI Specification - An object oriented approach to generating OpenAPI Descriptions, implemented in PHP	PHP	❌	✅
OpenAPI-TS - TS Model & utils for OpenAPI 3.0.x contracts	TypeScript	❌	✅
openapi3 - An OpenAPI 3 Specification client, and validator, covering both description validation and limited data validation for Python 3.	Python	❌	✅
OpenAPI3-Rust - Rust serialization library for OpenAPI v3	Rust	❌	✅
openapi3_parser - A Ruby implementation of parser and validator for the OpenAPI 3 Specification.	Ruby	❌	✅
openapi4j - Parse Description Document, validate api requests and responses using OpenAPI 3.x.	Java	❌	✅
php-openapi - A PHP library for manipulating and validating OpenAPI 3.0 Descriptions	PHP	❌	✅
psx-api - Parse and generate API specification formats	PHP	✅	✅
swagger-parser - Swagger Parser reads OpenAPI definitions into current Java POJOs.	Java	✅	✅

Testing

Quickly execute API request and validate responses on the fly through command line or GUI interfaces.

Name	Language	v2	v3
Assertible - Import an OpenAPI specification into Assertible to generate tests that validate JSON Schema responses and status codes on every endpoint.	SaaS	✅	✅
Chai OpenAPI Response Validator - Simple Chai support for asserting that HTTP responses satisfy an OpenAPI spec.	Node.js	✅	✅
Dredd - Language-agnostic command-line tool for validating API description document against backend implementation of the API	Javascript	✅	✅
EvoMaster - A tool for automatically generating system-level test cases for RESTful APIs, using Evolutionary Algorithms and Dynamic Program Analysis.	Java/Kotlin	✅	✅
hikaku - A library that tests if the implementation of a REST-API meets its specification.	Kotlin	❌	✅
OpenAPI Enforcer - Validate your OpenAPI document, serialize, deserialize, and validate incoming requests and outgoing responses, and simplify response building. You can even produce mock data.	Node.js	✅	✅
Schemathesis - Reads the description document and generates test cases which will ensure that your application is compliant with its description.	Python	✅	✅
Swagger Inspector - Swagger Inspector is a free online tool to quickly execute any API request, validate its responses and generate a corresponding OpenAPI Description.	Self-hosted/SaaS	✅	✅
Tcases for OpenAPI - Generates test cases directly from an OpenAPI v3 spec. Bonus: Semantic linter reports elements that are inconsistent, superfluous, or dubious.	Java	❌	✅
Unmock - API integration testing library that intercepts outgoing requests and serves back mock data based on the OpenAPI descriptions.	Node.js	❌	✅