OpenAPI.tools

@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.

@hey-api/openapi-ts

OpenAPI to TypeScript codegen. Production-ready SDKs, Zod schemas, TanStack Query hooks, and 20+ plugins. Used by Vercel, OpenCode, and PayPal.

@nest-openapi/mock

Spec-driven mock server for NestJS that generates realistic mock responses from OpenAPI.

@nest-openapi/serializer

High-performance response serialization for NestJS based on your OpenAPI spec using fast-json-stringify.

@nest-openapi/validator

Automatic request/response validation for NestJS based on your OpenAPI spec using AJV.

@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.

@smartrecruiters/openapi-first

Initializes your API express application with the description in OpenAPI 3.0 format using provided middlewares (parsers, validators, controller, defaults setting) or custom ones

// SDK-IT

Generates type-safe client SDKs from OpenAPI descriptions and creates OpenAPI descriptions from TypeScript code.

// Speakeasy

Generate & publish SDKs in 10+ languages, Terraform Providers, and docs from OpenAPI.

✨ Stainless

Generate SDKs in popular languages and publish them to package managers (like npm).

🛠️ Speakeasy OpenAPI

An OSS set of packages and tools used by Speakeasy for working with OpenAPI, Arazzo and Overlay Specification documents. Includes CLI tools for validation, bundling, inlining, upgrading, and more.

42crunch

A unique set of integrated API security tools that allow discovery, remediation of OpenAPI vulnerabilities and runtime protection against API attacks.

42Crunch IntelliJ OpenAPI Editor

OpenAPI extension for Visual Studio Code - new file templates, navigation, intellisense, code snippets.

ABAP OpenAPI Client & Server Generator

ABAP OpenAPI Client & Server Generator written in ABAP. Code generation runs also in the Browser and on command line using NodeJS.

Agentify

An agent interface compiler that transforms OpenAPI specifications into 9 agent-ready formats including MCP servers, AGENTS.md, CLAUDE.md, .cursorrules, Skills, llms.txt, GEMINI.md, A2A Card, and standalone CLI. Supports tiered generation strategies for APIs of any size.

allof-merge

Simplify your JsonSchema by combining allOf safely

Apache APISIX

APISIX API Gateway offers a variety of traffic management features, including load balancing, dynamic upstream, canary release, circuit breaking, authentication, observability, and more.

api

Create an SDK from an OpenAPI description use its codegen offering to create an opinionated SDK in TypeScript/JavaScript.

API Insights (RestCase)

RestCase executes hundreds of security and quality checks against the API definition, the API insights report provides detailed security scoring for prioritization, and remediation advice to help developers define the best API definition possible.

API Insights (Treblle)

API Insights is a web application and native Mac application that allows you get real time insights into your API using your OpenAPI specification. Think of it like a static analysis tool for your API, using your OpenAPI Specification file.

API Platform

REST and GraphQL framework to build modern API-driven projects

api-codegen-ts

Generates TypeScript models, response validators, and operation controllers from OpenAPI descriptions

api-diff-viewer

React component to view the difference between two JSON based API descriptions. Supported description formats: JSON Schema, OpenAPI 3.x, AsyncAPI 2.x.

Api-Fiddle

Opinionated API design platform built for collaboration and exploration. Create API designs for technical documents, governance, and reviews.

api-ref-bundler

Bundle all external $ref in Json based API document into single document

api-smart-diff

Compare two Json based API documents (OpenAPI, AsyncAPI, JsonSchema, GraphAPI)

API7 Enterprise Edition

A comprehensive API lifecycle management solution based on Apache APISIX, featuring a Developer Portal for onboarding.

ApiBldr

Web-based API Designer for OpenAPI and AsyncAPI descriptions.

APIClarity

Reconstruct OpenAPI descriptions from real-time workload traffic seamlessly.

Apicurio Studio

Web-Based Open Source API Design via the OpenAPI specification.

APIDevTools/swagger-parser

OpenAPI 2.0 and 3.0 parser and validator. Can also bundle multiple documents into one via `$ref`.

APIdog

A comprehensive, all-in-one API development platform that revolutionizes how teams design, test, and document APIs. Built for modern development workflows, Apidog combines powerful API documentation generation, robust testing capabilities, and intelligent mock servers into a single, intuitive platform.

APIFuzzer

Fuzz test your application using your OpenAPI definition without coding. Integrate into CI/CD, get Junit XML test result and JSON report of failures

apigen-ts

Typed HTTP client generator as single file without extra dependencies.

APIGit

the native Git based collaboration platform for API design, document, mock, testing and share.

APIMatic Developer Experience Portal

Customizable developer portals packed with language specific documentation, client libraries, code samples, an API console and much more.

APIMatic Generate

Bring in your API description (OAI v2/v3, RAML, API Blueprint, WSDL, etc.) to generate fully functional SDKs in over 10 languages.

APIMatic OpenAPI Linter - GitHub App

The APIMatic OpenAPI Linter GitHub App automatically validates and lints your OpenAPI definitions within GitHub repositories. Every time you create or update a pull request, the app ensures your API definitions meet high standards for both code generation and documentation generation, helping you maintain consistency and quality across your API projects.

APIMatic Transformer

Transform API Descriptions to and from RAML, API Blueprint, OAI v2/v3, WSDL, etc.

APIQuality

A low code tool for APIOps. Integrates all API Tools in one single platform, so you can develop your API-First cycle easily. Create API Templates with AI, simulate APIs with mocking tools and test your APIs before deployment.

Apitally

A simple API monitoring and analytics tool that helps engineering teams understand API usage, monitor performance, and troubleshoot issues. Offers opinionated dashboards, request logs with traces, uptime monitoring and alerts. Integrates via lightweight SDKs for 20+ frameworks across Python, Node.js, Go, .NET and Java.

Arazzo Editor

Build and edit Arazzo workflows with form-based editing and real-time diagrammatic representation. Export valid Arazzo 1.0.1 YAML, JSON, markdown, or HTML documents.

Arazzo Parser

TypeScript/JavaScript parser for Arazzo Specification documents. Parses Arazzo 1.0.0 and 1.0.1 documents from objects, strings, file paths, or URLs into a structured ApiDOM data model.

Arazzo Resolver

TypeScript/JavaScript resolver and dereferencer for Arazzo Specification and OpenAPI documents. Resolves all internal and external references inline, producing self-contained ApiDOM data models.

Arazzo UI

Visualize Arazzo workflows as interactive documentation. It provides diagram views, documentation views, and a split view combining both

arazzo-cli

Standalone Arazzo 1.0 workflow executor with runtime engine, debugger, and MCP server for AI agent integration.

arazzo2openapi

Convert Arazzo workflow documents into OpenAPI documents. Supports CLI and programmatic usage, with intelligent type inference from referenced OpenAPI source descriptions.

Assertible

Import an OpenAPI specification into Assertible to generate tests that validate JSON Schema responses and status codes on every endpoint.

Atlassian OpenAPI Request Validators

A set of Java libraries which allow you to integrate OpenAPI Description Document validation into your testing or clients with tools like WireMock/RestAssured/MockMVC/etc...

avantation

Generate OpenAPI 3.0 specification from HAR.

Azure AutoRest

Generates client libraries for accessing RESTful web services from an OpenAPI document. Supports C#, PowerShell, Go, Java, Node.js, TypeScript, Python, and Ruby.

Ballerina OpenAPI tool

The Ballerina OpenAPI tool enables the generation of Ballerina client and service skeleton from provided OpenAPI descriptions and facilitates the creation of OpenAPI v3.x descriptions for given Ballerina services.

Barbacane

Spec-driven API gateway that compiles OpenAPI specs into portable artifacts with WASM middleware plugins for validation, authentication, rate limiting, and more.

BaucisJS + baucis-openapi3

Create REST resources with persistence on MongoDB and expose OpenAPI v.3 contracts

Beeceptor OpenAPI Mock Server

🐝 A free service that transforms your OpenAPI description documents into instant mock servers with AI-generated realistic responses. Upload your YAML/JSON files to get schema-compliant mocks without writing any code. Helps with early integration testing and simulating various API behaviors.

BlocklyAutomation

Input any OpenAPI document to have generated Blocks in Blockly form to test and generate documentation.

BOATS

BOATS allows for larger teams to contribute to multi-file OpenAPI definitions by writing Nunjucks tpl syntax in YAML with a few important helpers to ensure stricter consistency, eg operationId: <$ uniqueOpId() $>.

Bruno

Bruno is a local, git-native, open source API client. Collections are authored as text files on your system allowing Git operations to be performed on them and ultimately have collections stored and versioned alongside your spec and codebase.

Bump.sh

Bump.sh generates elegant documentation and changelogs from your OpenAPI descriptions. Git diff, for your API. Integrates with CI and Slack. **PAID ONLY**

cats

CATS is a REST API Fuzzer and negative testing tool for OpenAPI endpoints. CATS automatically generates, runs and reports tests with minimum configuration and no coding effort. Tests are self-healing and do not require maintenance.

Chai OpenAPI Response Validator

Simple Chai support for asserting that HTTP responses satisfy an OpenAPI spec.

Chrome OpenAPI DevTools

Browser extension that generates API descriptions for any app or website.

Clio

Clio is a CLI to apply Overlays to OpenAPI descriptions. It's small, blazing fast and dedicated to applying Overlays really well. It's also available as a .net library in case you'd want to integrate overlay processing in your application.

CodeMirror OAS support

Plugin for text editor https://codemirror.net/ running in your browser that can fetch and parse your OpenAPI schema definition and provide auto-completion support (for large and complex JSON message payloads), error highlighting and access to schema documentation. It is capable of parsing megabytes of OpenAPI schema definition in a second and providing auto-completion support in milliseconds. The work is an MVP of a plugin with basic functionality made as part of a master thesis at ČVUT.

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).

Connexion

Connexion is a modern Python web framework that makes spec-first and api-first development easy. No code is generated. With Connexion, you write your server-side API handlers according to a naming convention, and the Connexion engine, given a spec, invokes your code after any input has been validated.

Counterfact

Counterfact is a revolutionary free and open source mock server. If you have Node installed, all you have to do is run `npx counterfact@latest path-or-url-to-your-openapi-document`. Out of the box, you'll get a mock server that returns random data. With a TypeScript API that's optimized for mocking, you can add more realistic behavior. It supports mix and matching mocks with calls to the real API (sans CORS headaches). With hot reloading and a REPL, you can change things up on the fly.

CUE

CUE is an open source language, with a rich set of APIs and tooling, for defining, generating, and validating all kinds of data configuration, APIs, database schemas, code, etc. CUE currently supports generating OpenAPI through its API.

Delimit

Catch breaking API changes before merge. 27 detection types (17 breaking, 10 non-breaking), semver classification, migration guides, and policy enforcement for OpenAPI specs. Works as a GitHub Action, CLI, and MCP server for AI coding assistants.

DeveloperHub

Collaboration platform for product and API documentation

Django REST Framework

Automates generation of OpenAPI 3 description documents either as a static file (via CLI command) or a dynamic view within the Django REST Framework (DRF) application.

django-contract-tester

Validate Django REST Framework (DRF) and Django Ninja APIs against their OpenAPI specification.

DocDriven

DocDriven is a user friendly GUI editor with collaboration features, cloud mock servers and AI code generation.

docler-labs/api-client-generator

API client generator is a console application capable of auto-generating a PSR18/PSR7 API client based on OpenAPI specification according to PHP best practices and your code style standards.

docs

A modern alternative to `go-swagger`. Offers generation and parsing of OpenAPI descriptions.

Docuo

Docuo is a lightweight platform that transforms your static contents into a modern developer hub, API reference, product guides, and more.

draig

DRAIG is an OpenAPI3 based design-first custom generator that creates fully functional microservices from an OAS API description document. You can use DRAIG with openapi-generator as a backend generator or use DRAIG CLI or REPL to generate your microservices. With simple user-customizable templates, you can extended and improve implementation code so that generated code can be compiled and deployed immediatelly.

draig-car

This is a REPL OpenAPI3 description document text editor. It provides both a CLI and and a REPL you can use to test your APIs, but you can also test database queries, start and stop database (containers), generate fake data automatically, start your test microservice and much more. You don't have to exit from your REPL! Or you can use the CLI to do the same if you want, giving you the option to automatize your contract-first based dev cycles.

Dredd

Language-agnostic command-line tool for validating API description document against backend implementation of the API

drf-spectacular

Flexible OpenAPI description generation for Django REST framework.

Elements

Build beautiful, interactive API Docs with embeddable React or Web Components, powered by OpenAPI and Markdown

EvoMaster

A fuzzer for automatically generating system-level test cases for REST APIs, using Evolutionary Algorithms and Dynamic Program Analysis.

express-openapi

An unopinionated OpenAPI framework for Express, which supports Promise based middleware, response handlers and Security Filtering.

express-openapi-validator

🦋 Auto-validate API requests and responses in ExpressJS.

FabriKt

A sophisticated Kotlin code generation library capable of generating Jackson-annotated data classes, Spring Controller interfaces, and fault-tolerant OkHttp clients. Written in Kotlin, this library programmatically generates code and is capable of handling advanced OAS features such as polymorphism.

Fakeit

Create mock server from OpenAPI 3 specification with random response generation and request validation.

Falcon Heavy

The framework for building app backends and microservices via the API design-first workflow.

FastAPI

FastAPI framework, high performance, easy to learn, fast to code, ready for production. A modern, fast web framework for building APIs with OpenAPI as a first-class citizen.

fastify-openapi-glue

A plugin for the Fastify webserver to autogenerate a Fastify configuration based on a OpenApi description.

FastMCP

FastMCP can automatically generate an MCP server from an OpenAPI specification. Users only need to provide an OpenAPI specification (3.0 or 3.1) and an API client.

Fern SDKs & Docs

Generate SDKs in popular languages and publish them to package managers (like npm), plus beautiful API documentation.

Fern Server

Generate server-side boilerplate code from OpenAPI and then implement your business logic.

Fitting

Library add improve test log for RSpec and WebMock, validate it according to API Blueprint and OpenAPI, show the documentation coverage with log.

Fix My OpenAPI - A VSCode Extension by APIMatic

APIMatic's VSCode extension helps you validate, lint, and auto-fix your OpenAPI files, along with other capabilities such as API transformations, API audit report generation, SDKs generation, and more.

Flotiq - headless CMS with OpenAPI support

Visually define your Content Types, Flotiq automatically generates your own OpenAPI v3 compatible endpoints, SDKs and Postman collections.

Framna Docs

Self-hosted web portal that centralizes OpenAPI documentation and facilitates spec-driven development, built with GitHub-based authorization. Integrates with Swagger UI, Stoplight Elements, and Redocly.

Frevo

Keep track of changes in your OpenAPI descriptions & generate API references ⛱️

Frogment Editor

A free openAPI spec editor and linter that breaks down your spec into fragments to make editing easier and more intuituve.

Fuego

Golang Fuego - web & API framework generating OpenAPI descriptions from source code.

Fusio

Open source API management platform

generator-openapi-repo

Generate the repository structure for a scalable OpenAPI Description

GitBook

Effortlessly publish stunning, interactive documentation for products, APIs, and more.

go-openapi-spec-code-diffs

A golang validation tool that compares given OpenAPI descriptions vis-a-vis routes (e.g. /api/v1/customer/:id) defined in golang source code and reports differences. This is useful in scenarios where you want to keep the OpenAPI descriptions and code in sync.

go-swagger

Unmaintained v2.0 only project seeking new maintainer, or probably a fork. Parser, validator, generates descriptions from code, or code from descriptions!

Goa

Goa provides a holistic approach for developing remote APIs and microservices in Go. implementers don't have to worry about the documentation getting out of sync as Goa takes care of generating OpenAPI descriptions for HTTP based services and gRPC protocol buffer files for gRPC based services

Google Gnostic

Compile OpenAPI descriptions into equivalent Protocol Buffer representations

Gram

A platform and TypeScript framework for building, deploying, and running MCP-based tools and applications. Generate complete MCP toolsets from OpenAPI specifications, create custom agent tools, and deploy with serverless scale. Includes managed infrastructure, OAuth support, and built-in observability.

guardrail

Principled code generation from OpenAPI descriptions

Hackolade

A visual editor for OpenAPI v2/v3, from the pioneer in data modeling for NoSQL databases.

har-to-openapi

Automatically generate OpenAPI 3.0 Spec by using network requests captured in one or more HAR files

har2openapi

Automatically generate OpenAPI 3.0 Spec by using network requests captured in one or more HAR files.

hidi

Convert, validate, transform or filter OpenAPI descriptions effortlessly

hikaku

A library that tests if the implementation of a REST-API meets its specification.

HopFront

HopFront automatically builds an user friendly UI from a collection of OpenAPI descriptions. You can setup custom dashboard tailored to the way your interact with your APIs.

Hot Potato

A reverse proxy that validates responses against an OpenAPI description. It can be used as either a standalone .NET tool, or installed as NuGet packages for an ASP.NET Core integration testing project.

Huma

A modern, simple, fast & flexible micro framework for building HTTP REST/RPC APIs in Go backed by OpenAPI 3 and JSON Schema.

InducOapi

A simple python module to generate OpenAPI Description Documents by supplying request/response bodies.

Inspectr

Observe, mock and test APIs using OpenAPI. Inspectr is a real-time HTTP inspection and debugging tool for APIs and webhooks, built around OpenAPI documents. It helps developers observe live traffic, mock backends, monitor MCP server activity, and debug integrations during development and testing.

janephp

Generate a PHP Client API (PSR-7 compatible) given a OpenAPI specification.

jekyll-openapi

An OpenAPI 3 documentation website generator built with Jekyll for use on GitHub Pages.

jest-openapi

Additional Jest matchers for asserting that HTTP responses satisfy an OpenAPI spec.

JetBrains tools (IntelliJ IDEA, PyCharm etc.)

JetBrains development tools like IntelliJ IDEA, PyCharm and others come with a bundled *OpenAPI Specifications* plugin. The plugin allows you to write the OpenAPI descriptions and supports you with validations, formatting, code-completion etc. It supports a *text view* as well as a rendered SwaggerUI-like *graphical interface*.

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.

JSONSchema::Validator

A Perl library which validates request/response according to an OpenAPI specification

KaiZen OpenAPI Parser

High-performance Parser, Validator, and Java Object Model for OpenAPI 3.x

KaiZen-OpenAPI-Editor

Full-featured Eclipse editor for OpenAPI, also available on Eclipse Marketplace.

Kappa

Java validation middleware which can be used to validate HTTP requests and responses against OpenAPI 3.1 definitions based on popular but archived openapi4j. Works with Spring and Vert.x.

Karate-IDE

Generates KarateDSL Tests and Mocks from OpenAPI 3.0 documents and so you can quickly test/explore your API.

kin-openapi

OpenAPI 3.0 (and Swagger v2) implementation for Go (parsing, converting, validation, and more)

Kiota

Kiota is a cross platform API Client code generator that is small, fast, and optimized for API consumers to find APIs and generate client code for just the parts of the API that they need. One tool, for any OpenAPI described API, that delivers a consistent client experience in multiple languages.

Kong Enterprise Edition

Highly customizable developer portal with developer onboarding, integrated with the Kong API Gateway

kotlin-openapi3-dsl

kotlin-openapi3-dsl is a DSL written in Kotlin to write OpenAPI descriptions in plain Kotlin.

KrakenD API Gateway

KrakenD is a high-performance, stateless API Gateway, seamlessly integrated with OpenAPI. It facilitates automatic API documentation and provides the capability to import existing specifications for generating configuration and mock servers.

kubb

Kubb is a tool that can generate TypeScript types, Zod schemas, react-query hooks and much more. It has support for Tanstack Query(React, Solid, Svelte and Vue), SWR(React), Zod, Zodios and Axios. Kubb is made based on a plugin system, meaning you can create your own plugin and couple it with the Kubb ecosystem.

Kusk Gateway

Kusk-Gateway is an OpenAPI-driven API Gateway for Kubernetes. It empowers you to develop, validate, mock and deploy your APIs in a matter of minutes using both manual and automated GitOps/APIOps workflows.

LAP

Compiles API specs into lean, token-efficient formats for AI coding agents. Prevents hallucinated API calls with 1,500+ pre-compiled specs.

laravel-openapi

Generate OpenAPI 3 specification for Laravel Applications.

Legba

Clojure library for building OpenAPI services. Provides rock solid, full coverage of OpenAPI 3.1 description with validation, routing, and overlay support.

libopenapi

Enterprise grade, fully featured OpenAPI 3.1, 3.0 and Swagger parser library for go. A complete toolset for reading and parsing OpenAPI and Swagger specifications. Comes complete with high and low-level APIs, diff engine, index and resolver.

LoopBack 4

A highly extensible object-oriented Node.js and TypeScript framework for building APIs and microservices with tight OpenAPI 3 integration. Serves Swagger UI and OpenAPI 3 spec out of the box. Generate code to interact with other OpenAPI-compliant APIs, or generate new API endpoints based on existing OpenAPI descriptions.

Mayhem for API

Probe your REST API with an infinite stream of test cases generated automatically from your OpenAPI specification.

Meeshkan

Meeshkan is an automated testing and mocking tool. It offers first-class support for GraphQL APIs, but Meeshkan is also built to handle REST APIs and third-party dependencies.

Membrane API Gateway

Open source API gateway with built-in OpenAPI support. Turn OpenAPI descriptions into APIs and enforce request and response validation.

Microcks

Open source Kubernetes-native tool for API Mocking and Testing. Turn your OpenAPI into ready-to-use mocks. Use examples to test and validate implementations according to OpenAPI (and similar) elements. Microcks is a Cloud Native Computing Sandbox project.

Microsoft/OpenAPI.NET

C# based parser with OpenAPI Description validation and migration support from V2

middleBrick

Automated API security scanner that assigns quantified risk scores. Runs 12 parallel security checks covering OWASP API Top 10 plus 18 adversarial probes for AI/LLM endpoints. Supports REST and GraphQL. Available as CLI, GitHub Action, and MCP Server.

Mintlify

Modern standard for API documentation. Beautiful and easy-to-maintain UI components and interactive playground.

mitmproxy2swagger

A tool for automatically converting mitmproxy captures to OpenAPI 3.0 specifications. Automatically reverse-engineer REST APIs by just running the apps and capturing the traffic.

MkDocs Redoc Tag

A MkDocs plugin supports adding Redoc to the page.

MkDocs Swagger UI Tag

A MkDocs plugin supports for add Swagger UI in page.

Mockintosh

Mocks for CloudNative Environments - Converts OpenAPI files to Mocks and use them to develop in isolated environments and test edge cases, Async call to queues such as Kafka or RabbitMQ or simulate performance & chaos testing

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.'

Mojolicious::Plugin::OpenAPI::Modern

Mojolicious plugin for OpenAPI::Modern

Mokapi

Mock your APIs – Spin up realistic mocks from OpenAPI, AsyncAPI, LDAP, or SMTP/IMAP files. Extend them with simple JavaScript to simulate real-world scenarios, test microservices, Kafka streams, or email workflows, and integrate seamlessly into CI/CD pipelines. Free, open-source, and fully under your control.

mondrian-framework

Framework for generating OpenAPI 3.1 documents and servers from formal TypeScript definitions of models and services. Includes built-in data validation.

MrinDoc

OpenAPI description document viewer.

Nexmo OAS Renderer

Ruby OpenAPI docs rendering, use standalone or add to your Rails app

NSwag

OpenAPI toolchain for .NET, Web API and TypeScript

oa-client

Flexible client helper for making and validating calls to OpenAPI backends. For Node and the browser. Runtime lib - no need for code generation!

OAIE Sketch

Browser based OpenApi Integrated Editor with side-by side view of the yaml and an interactive graph.

oapi-bundler

oapi-bundler merges modular OpenAPI files (YAML/JSON) into one output OpenAPI document. It is designed for real-world spec trees where files are split by domain, operation, or component and connected with $ref

oapi-codegen

Generate a client, server, and HTTP types for various Go HTTP servers, from an OpenAPI v3 specification

oas

Comprehensive tooling for working with OpenAPI definitions

OAS RAML Converter

Converts API descriptions between OpenAPI and RAML.

oas_parser

A Ruby parser for OpenAPI 3.0+ descriptions.

oas_rails

OasCore is a Ruby gem designed to generate OAS documentation directly from YARD comments in your endpoints. It serves as the core engine for OAS generation, while framework-specific adapters like OasRails (for Ruby on Rails) handle the extraction, integration and additional features.

oas-normalize

Comprehensive tooling for working with OpenAPI definitions.

oas-overlay-java

Java library for processing OpenAPI Overlay documents.

oas-patch

A command-line tool for OpenAPI Overlays, allowing you to patch and modify OpenAPI documents. And create overlays from two openapi documents

oas-tools

NodeJS module to manage RESTful APIs defined with OpenAPI 3.0 Description over Express servers, including security validations

oas3-api-snippet-enricher

Enrich your existing description documents with generated code samples

oasdiff

Golang module for deep comparison of two OpenAPI descriptions. Available also as a command-line.

oaswrap/spec

A lightweight, framework-agnostic OpenAPI 3.x specification builder for Go that generates API docs programmatically using pure Go code without annotations.

OAuth2 as OpenAPI Spec 3.0 components

OAuth2 token endpoint described with OAS3 schema. All grants documented. Can be installed as NPM or Composer package.

oazapfts!

Generate TypeScript clients from a given OpenAPI description document.

Object Oriented OpenAPI Specification

An object oriented approach to generating OpenAPI Descriptions, implemented in PHP

OData.OpenAPI

Convert an Edm (Entity Data Model) to OpenAPI 3.0

OData.OpenAPI (.NET)

Convert an Edm (Entity Data Model) to OpenAPI 3.0

OpenAPI Client Generators

.NET Core command line program to generate strongly typed client API codes in C# on .NET Frameworks and .NET Core, and in TypeScript for Angular 5+, Aurelia, jQuery, AXIOS and Fetch API.

OpenAPI Commander

Generate a Node.js command line tool from an OpenAPI definition.

OpenAPI CRUD Wizard

This wizard is an IntelliJ Plugin to create a new OpenAPI document including all CRUD operations based only on a Yaml object. No knowledge about OpenAPI specification needed.

OpenAPI Designer

OpenAPI Designer is an easy-to-use, free, web-based, codeless description document editor with JSON and YAML outputs.

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.

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.

OpenAPI Explorer

Generate and render fully customizable API documentation, then explore and execute API requests via the integrated console.

OpenAPI Generator

A template-driven engine to generate API clients (a.k.a SDKs) and server stubs in over 50 languages (Go, Groovy, Java, Kotlin, PHP, Python, Ruby, Rust, Scala, TypeScript, etc.)

OpenAPI HttpFoundation Testing

Validate your HttpFoundation requests and responses (Symfony, Laravel, Drupal...) against OpenAPI definitions

OpenAPI JSON Schema Generator

A template-driven engine to generate API client code + documentation by parsing your OpenAPI Description

OpenAPI Mocker

Standalone nodejs based OpenAPI 3 mock server, docker-friendly with request validation and autoreload.

OpenAPI Qraft

Generate a type-safe TanStack Query client for React from an OpenAPI Document.

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.

OpenAPI Style Validator

A customizable style validator to make sure your OpenAPI description follows your organization's standards.

OpenAPI TypeScript

Convert static OpenAPI schemas to TypeScript types quickly using pure Node.js. Fast, lightweight, (almost) dependency-free, and no Java/node-gyp/running OpenAPI servers necessary.

OpenAPI Validator

Configurable and extensible validator/linter for OpenAPI documents

openapi_first

It validates requests and responses against your API description using rack middlewares or a low-level interface. It gives you access to request parameters that are parsed exactly as described in your API description and produces useful customizable error responses if request validation fails.

openapi-backend

Build, Validate, Route, and Mock using OpenAPI specification. Framework-agnostic

openapi-changes

The world's fastest, most beautiful, powerful and detailed OpenAPI change detection tool on earth. Explore every change in An OpenAPI spec. See changes over time, go back into history and see what changed with each commit. Identifies all breaking changes, Powered by libopenapi.

openapi-cli-tool

Can list up defined API paths and bundle multi-file into one. Supports multiple file extensions.

openapi-code-generator

A code generation tool for openapi 3 / 3.1, and typespec specifications, primarily aimed at generating typescript client SDKs, and server stubs, with an emphasis on compile & runtime safety.

openapi-comparator

C# library for comparing two OpenAPI descriptions.

openapi-core

Validate your requests and responses against an OpenAPI 3 specification and get very verbose and human-readable descriptions of errors. You will receive a deserialized object along with validation result, so you won't need to deserialize it twice.

openapi-data-mocker

Tiny library to generate basic OpenAPI Data Types. Consider it as extended Faker package. First version able to mock most of the data formats. It doesn't support polymorphism yet, but work in progress. May be useful for writing custom unit tests.

openapi-data-validator

Validate API requests against an OpenAPI schema. Lightweight, focused, and integrates with any framework

openapi-dev-tool

OpenAPI Dev Tool proposes to developers a unique tool to address development and industrialization needs!

openapi-diff

Utility for comparing two OpenAPI descriptions.

openapi-examples-validator

Validates embedded JSON-examples in OpenAPI-specs

openapi-filter

OpenAPI 2.0 and 3.0 filter utility. A CLI/module to filter out internal/private paths, operations, parameters, schemas etc from OpenAPI v1/OpenAPI v2/AsyncAPI definitions. Simply flag any OpenAPI object within the definition with an `x-internal` specification extension or target a OpenAPI property (tags, methods, OperationId), and it will be removed from the output.

openapi-format

A CLI to format an OpenAPI document by ordering fields in a hierarchical order, with the option to filter out flags, tags, methods, operationIDs; including the option to convert between OpenAPI 3.0, 3.1 and 3.2.

openapi-fuzzer

Based on OpenAPI specification, openapi-fuzzer provides random data as inputs to the API endpoints in order to find bugs.

openapi-merge

A simple tool to merge multiple independent OpenAPI description files into one file. Useful when you have a number of microservices and you decide to expose them through a gateway.

openapi-overlays-dotnet

A dotnet implementation of OpenAPI overlays which relies on Microsoft.OpenAPI. Includes both a library and CLI tool for applying overlays to OpenAPI documents.

openapi-overlays-js

Apply overlays to OpenAPI descriptions with this handy NodeJS library and CLI.

openapi-processor

Generates java interfaces & DTOs (pojo or record) for Spring Boot (annotation based, MVC & WebFlux) or Micronaut (annotation based) from an OpenAPI YAML/JSON description. Provides powerful type mapping capabilities to adjust the generated code. Gradle & Maven support. Playground.

openapi-processor/openapi-parser

OpenAPI parser with (JSON schema) validation. Separate APIs for OpenAPI 3.2, 3.1, 3.0. Easily get resolved $ref objects. Pluggable document reader & JSON/YAML converter. Minimal dependencies.

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.

openapi-python-client

Generate modern Python clients from OpenAPI 3.0 documents.

openapi-request-response-validation

Runtime validation of requests and responses of your API according to the OpenAPI descriptions, returning (if any) the list of errors found. It is integrated via a simple REST API therefore usable by Java and non-Java applications and CI/CD.

openapi-schema-validator

OpenApi description validation

openapi-snippet

Generates code snippets in various languages & tools (cURL, Node, Python, Ruby, Java, Go, C#...), from OpenAPI documents.

openapi-snippet-cli

Adds code snippets in redoc style (x-codeSamples) to OpenAPI documents. This is a CLI wrapper for the "openapi-snippet".

openapi-spec-validator

OpenAPI Description validator

openapi-spring-webflux-validator

A friendly kotlin library to validate API endpoints against an OpenAPI description document.

openapi-to-hurl

A CLI to convert OpenAPI 3.1 Description Documents to hurl test files

openapi-to-postman

Convert OpenAPI and Swagger specs to the Postman Collection (v2) format

OpenAPI-TS

TS Model & utils for OpenAPI 3.0.x contracts

openapi-ts-sdk-builder

Generate a TypeScript SDK from OpenAPI 3 definitions.

openapi-validator-bundle

Validates Request and Response using Symfony Framework

openapi-validator-junit

A JUnit extension for validating a wide range of properties of a specification.

openapi-validator-middleware

Provides data validation within an Express, Koa or Fastify app according to a OpenAPI definition. It uses Ajv under the hood for validation.

openapi-viewer

Browse and test a REST API described with the OpenAPI 3.0 Specification

OpenAPI::Modern

OpenAPI v3.0, v3.1, v3.2 validator and JSON Schema validator (drafts 4 through draft2020-12)

openapi.tanna.dev/go/validator

A Go library for making it easier to validate that your OpenAPI contracts match your HTTP request/responses used in your tests. Based on kin-openapi.

openapi3

An OpenAPI 3 Specification client, and validator, covering both description validation and limited data validation for Python 3.

OpenAPI3 Fuzzer

Simple fuzzer for OpenAPI 3 specification based APIs. Verifies responses and sends various attack patterns.

openapi3_parser

A Ruby implementation of parser and validator for the OpenAPI 3 Specification.

OpenAPI3-Rust

Rust serialization library for OpenAPI v3

OpenApi4s

OpenApi generators for Scala. Direct code generation, minimally intrusive and with automatic refactoring.

OpenAPIKit

Codable Swift types that encode to- and decode from OpenAPI 3.0.x and OpenAPI 3.1.x Documents and their components.

OpenApiSpecGeneratorPlugin

Built-in plugin for open-source DevProxy that automatically generates OpenAPI 3.0 Spec from captured network requests.

Openapiviewer

Upload a openapi.json and view it online via a shareable link. Nothing else. Uses OpenAPI Explorer under the hood.

OpenDocumenter

OpenDocumenter is a automatic documentation generator for OpenAPI v3.0 schemas. Simply provide your schema file in JSON or YAML, then sit back and enjoy the documentation.

optic

Build your first OpenAPI description from traffic. Use Optic to patch the OpenAPI every time it detects new API behavior.

optic diff

Diff the effective API contract between any two versions of your OpenAPI description. Exit 1 on breaking changes.

orval

orval is able to generate client with appropriate type-signatures (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification, either in yaml or json formats. Generate, valid, cache and mock in your frontend applications all with your OpenAPI specification. 🍺

Overlay Playground

Mess around with Overlays for OpenAPI in this online playground. Upload your OpenAPI document and one or more overlays to see the combined result.

Oxlip API Language

Oxlip is a high-level functional programming language for designing OpenAPI definitions. It defines algebraic abstractions over REST concepts to alleviate the pain of managing OpenAPI in JSON or YAML by hand and at scale.

php-openapi

A PHP library for manipulating and validating OpenAPI 3.0 Descriptions

php-openapi-faker

Library to generate fake data for OpenAPI 3.x requests, responses and schemas.

portman

Port OpenAPI Spec to Postman Collection, with contract & variation tests included!

Prism

Turn any OAI file into an API server with mocking, transformations, validations, and more.

psx-api

Parse and generate API specification formats

Python OpenAPI Generator

This library facilitates creating OpenAPI document for Python projects.

Rage

A Ruby web framework for building APIs with first-class OpenAPI support.

RapiDoc

Custom Element to view OpenAPI descriptions.

RapiPdf

Custom Element to generate PDF from OpenAPI descriptions.

Rate My OpenAPI

Free and open source OpenAPI automated review and validation tool.

ReadMe

Interactive developer hubs that help users succeed with your APIs 🦉

ReadyAPI

an end to end API functional, security, performance and virtualization tool where OAS description documents can be utilized to automate the creation and validation of end to end tests, running them manually or at any point in your CI/CD pipeline. pipelines.

ReDoc

Open source API reference docs from OpenAPI descriptions

Redocly CLI

Bring versatile OpenAPI validation, linting & bundling to your command line with this open-source Swiss-army knife.

Redocly VSCode Extension

Redocly OpenAPI is a Visual Studio Code extension that helps you write, validate, preview, and maintain your OpenAPI documents.

Response2Schema

Takes any JSON response and generates an OpenAPI definition document with the component schema and a default endpoint.

RestCase Designer

A design-first API management platform with WYSIWYG API Designer for OpenAPI and AsyncAPI.

RestCase Docs

An API-first and security-first management platform. Design visually and we will create a beautiful API documentation for your APIs.

RESTest

RESTest is a framework for automated black-box testing of RESTful web APIs. It follows a model-based approach, where test cases are automatically derived from the OpenAPI description document (OAS) of the API under test.

restful-react

Generate React hooks with appropriate type-signatures from OpenAPI descriptions

Restish

A CLI for REST-ish APIs with HTTP/2, built-in auth, content negotiation, caching, and more that understands and can discover OpenAPI descriptions.

RESTler

RESTler is the first stateful REST API fuzzing tool for automatically testing cloud services through their REST APIs and finding security and reliability bugs in these services. RESTler analyzes the OpenAPI description of a cloud service, and then generates and executes tests that exercise the service through its REST API. During testing, it checks for specific classes of bugs and dynamically learns how the service behaves from prior service responses.

rswag

Rswag extends rspec-rails request specs with a Swagger-based DSL for describing and testing API operations.

Scalar

Beautiful Open-Source API references from Swagger/OAS files ✨

schema2dts

Create types definitions from an OpenAPI schema.

Schemathesis

Automatically generates test cases from OpenAPI and GraphQL schemas using property-based testing to find crashes, validation bugs, and specification violations.

Scramble

Modern Laravel OpenAPI documentation generator. No PHPDoc annotations required.

Scribe

Generate API documentation for humans from your Laravel codebase.

Serverless API Gateway

Serverless API Gateway is a serverless, open-source, and free API Gateway that is designed to be used with any HTTP source.

Sourcemeta JSON Schema Standard Library

A growing collection of battle-tested schemas (ISO, IETF, IEC, W3C, etc) to power your next API spec, so you never have to bother with JSON Schema again

Sourcey

Static documentation generator for OpenAPI specs and markdown. Outputs a complete docs site with API reference, guides, and search.

Specmatic

Specmatic enables teams to practice Contract-Driven Development by leveraging OpenAPI descriptions as Executable Contracts to reduce time-to-market by allowing teams to build, test and deploy their MicroServices and MicroFrontends independently and Shift-Left the identification of compatibility issues between Components / Services in complex interdependent systems such as those built with MicroServices architecture. In the process it reduces / removes the need for Integration Testing.

Spectator

Spectator provides light-weight OpenAPI testing tools you can use within your existing Laravel test suite.

Spectral

A flexible OpenAPI/AsyncAPI API linter, which can help you build anything from automated API Style Guides for API Governance workflows, or handle any other JSON/YAML object linting with custom functions.

Specway

API documentation platform with live OpenAPI spec sync, AI chatbot, breaking change detection, and interactive playground.

Spot

A concise, developer-friendly way to describe your API contract.

spring-openapi

OpenAPI v3 generator for Java Spring. Includes also client generation. Supports inheritance with discriminators, Jackson annotations and custom interceptors.

Springdoc

A Java library that automates the generation of API documentation using Spring Boot projects. It works by examining an application at runtime to infer API semantics based on Spring configurations, class structure and various annotations.

StackHawk HawkScan

StackHawk is an application vulnerability scanner purpose built for developers to use in the DevOps pipeline. It leverages a provided OpenAPI v2 or v3 spec file for route discovery and enhanced scanning.

Step CI

Open-source framework for API Quality Assurance. Generate multi-step test-scenarios from OpenAPI. Validate responses against description documents and more.

Stoplight Docs

Create beautiful, customizable, interactive API documentation generated from OpenAPI, powered by Stoplight Platform.

Stoplight Studio

Stoplight Studio is a powerful GUI/text editor with linting and mocking built right in. The desktop version has been discontinued, but it runs in the browser, powered by your existing GitHub, GitLab, or BitBucket repos.

super-linter

GitHub Action to lint repositories as part of CI/CD. Implements the latest version of Spectral.

Supermodel

Model your data using JSON Schema, refer and remix the models freely, convert to various formats including OAS v2/v3.

Swagger Core

Examples and server integrations for generating the Swagger API Specification, which enables easy access to your REST API.

Swagger Editor

Design, describe, and document your API on the first open source editor fully dedicated to OpenAPI-based APIs.

Swagger PHP

Generate interactive OpenAPI documentation for your RESTful API using PHP attributes or doctrine annotations.

Swagger-Codegen

Swagger Codegen enables generating server stubs and client SDKs for APIs described in OpenAPI

swagger-coverage-cli

A Node.js CLI tool to measure test coverage of OpenAPI descriptions using Postman collections or Newman run reports. Features smart endpoint mapping with intelligent status code prioritization and enhanced path matching.

swagger-jsdoc

Generates OpenAPI descriptions based on jsDoc comments and YAML files.

swagger-parser

Swagger Parser reads OpenAPI definitions into current Java POJOs.

swagger2openapi

Upgrade files from OpenAPI v2.0 to v3.0, bundling into one mega file or respecting $refs. Part of oas-kit.

SwaggerHub

API design and documentation platform to improve collaboration, standardize development workflow and centralize their API discovery and consumption.

Swaggie

Swaggie is an OpenAPI 3.x code generator that produces fully typed TypeScript API clients from JSON or YAML specs. It supports multiple client templates (fetch, axios, xior, SWR, TanStack Query, Angular), and robust schema handling for real-world APIs.

Swashbuckle

Documenting API's built on ASP.NET Core

Swift OpenAPI Generator

Generate Swift client and server code from an OpenAPI document. Includes support for type-safe JSON event streaming, multipart, Swift concurrency, customizable middlewares, and pluggable HTTP libraries.

Tcases for OpenAPI

Generates test cases directly from an OpenAPI v3 description of your API. Creates tests executable using various test frameworks. Bonus: Semantic linter reports elements that are inconsistent, superfluous, or dubious.

The Codegen Project

Stop wasting time on manual code. Generate payloads, parameters, headers, types, client wrappers, and more from your OpenAPI document!

Traefik Hub

Traefik Hub is a Kubernetes-native API Management solution for publishing, securing, and managing APIs. Configuration is driven by Kubernetes CRDs, labels, and selectors for effective GitOps.

Treblle

Treblle is a lightweight SDK that helps Engineering and Product teams build, ship, and maintain REST based APIs faster.

ts-oas

Automatically generate OpenAPI descriptions from lovely Typescript types.

tsoa

Build OpenAPI-compliant REST APIs using TypeScript and Node, and power runtime validation for Koa, Express, Hapi (and more) services. (v7.0.0 alpha supports OpenAPI v3.1)

typeconv

typeconv is an extremely fast silver bullet type conversion utility. It converts between any of its supported types, bidirectionally. typeconv lets you convert between type systems which have core-types converters, such as JSON Schema, TypeScript, GraphQL, OpenAPI and SureType. This package can be used as an API programatically or as an application (installed in node_modules/.bin or by using e.g. npx).

TypeSpec

Emit OpenAPI descriptions from an elegant DSL using the TypeScript-like TypeSpec language.

Typoas

Fully typed OpenAPI Typescript generator

Unchase.OpenAPI.Connectedservice

Visual Studio extension to generate C# (TypeScript) HttpClient (or C# Controllers) code for OpenAPI web service with NSwag.

vacuum

A blazing fast OpenAPI linter and validator that is compatible with Spectral rulesets, and designed for enterprise-grade speed and scale.

vacuum OWASP

OWASP API security ruleset for vacuum, implementing Open Worldwide Application Security Project (OWASP) API security rules to identify and prevent common API security vulnerabilities in OpenAPI specifications.

Vert.x Web Api Contract

Create API endpoints with Vert.x 3 and OpenAPI 3 with automatic requests validation

vitepress-openapi

Generate VitePress API Docs from OpenAPI descriptions.

vREST NG

vREST NG is a simple and powerful application for API Automation. It Allows to use OpenAPI specification into vREST NG to drive your API testing that validates the API responses against JSON Schema and also provides powerful response validation capabilities.

VSCode OpenAPI Editor

OpenAPI extension for Visual Studio Code - new file templates, navigation, intellisense, code snippets.

VSCode OpenAPI Preview

Preview OpenAPI v3.0 & v3.1 documents in Visual Studio Code using Spotlight Elements.

VSCode OpenAPI Snippets

OpenAPI Snippets for Visual Studio Code editor, includes split file validation

VSCode OpenAPI Viewer

Preview and edit JSON or YAML OpenAPI descriptions in Visual Studio Code using RapiDoc.

Whook

OpenAPI 3 based NodeJS server.

widdershins

Generate Slate/Shins markdown from OpenAPI 2.0/3.0.x

Wiremock Cloud

WireMock Cloud is a complete API simulation tool, built by the team behind the WireMock open source library. It provides a fully-managed mock server that can be deployed anywhere with broad protocol support including REST, GraphQL, SOAP, and gRPC. WireMock Cloud is a popular choice for larger teams thanks to advanced capabilities such as stateful mocking, chaos testing, OpenAPI generation, AI-native features via MCP, collaboration, and prototyping.

wiretap

Wiretap is a feature packed OpenAPI compliance testing tool. Validate that a client and server are compliant with an OpenAPI spec. Rewrite paths, inject headers, and even host a UI locally to test an OpenAPI implementation.

WuppieFuzz

WuppieFuzz is a coverage-guided REST API fuzzer developed on top of LibAFL, targeting a wide audience of end-users, with a strong focus on ease-of-use, explainability of the discovered flaws and modularity. WuppieFuzz supports all three settings of testing (black box, grey box and white box).

Xapi Platform

Xapi is an integrated platform that enables you to implement a streamlined API-first design strategy with standardized API artifacts and collaborative teams.

xyd

A new scalable docs framework. Generate API Docs from OpenAPI definitions easier. Powered by LiveSession.

Yaak

A fast, secure, and offline API client that works with Git. This is the same developer who originally created Insomnia (before it was sold to Kong who ruined it with AI nonsense.)

yii2-app-api

Generate Server side API code with routing, models, data validation and database schema from an OpenAPI description. Based on Yii Framework.

Zed Attack Proxy (ZAP)

Zed Attack Proxy (ZAP) by Checkmarx is a free, open-source penetration testing tool. ZAP is designed specifically for testing web applications and is both flexible and extensible. It works with OpenAPI descriptions and can be used for automated scans as well as a set of tools that allow you to find security vulnerabilities manually.

Zudoku

OpenAPI powered, highly customizable, API reference and documentation framework with CDN packaged and self-hosted options.

Zuplo (OpenAPI-based gateway and documentation)

Zuplo is an API gateway designed for developers. Natively powered by OpenAPI, zuplo offers an OpenAPI design surface, API documentation and a serverless, programmable edge gateway that includes request validation, auth, rate-limiting and more.