Open-source API libraries on GitHub — REST and GraphQL servers, API gateways, clients and schema tooling, ranked by stars and reviewed by TopGit.
free-for.dev is a curated GitHub list of SaaS, PaaS, and IaaS offerings with free tiers, maintained by ripienaar and scoped to services infrastructure developers actually use: cloud providers, cloud management tooling, source code hosting, and APIs/data/ML services, among other categories. The repository has been built through pull requests, reviews, and ideas from the community.
JSON-Server is an open-source Node.js tool from typicode that generates a REST API from a single JSON file, with full CRUD routes, query-param filtering, sorting, pagination, and relationship embedding built in. The GitHub repository and the project is MIT licensed. The current README documents a v1 beta; a separate v0.17.4 branch remains the stable release.
Dear ImGui is an open-source C++ library at ocornut/imgui for building graphical interfaces inside your own application, described in its own README as bloat-free and renderer agnostic. It targets content-creation tools, visualization panels, and debug UI for game engines and real-time applications rather than end-user software, and ships with officially maintained backends for DirectX, OpenGL, Vulkan, Metal, WebGPU, and more.
Gatsby is a React framework that generates websites at build time, then lets individual pages opt into deferred or server-side rendering when static output isn't enough. It ships as an open-source, MIT-licensed monorepo of npm packages, and its main pitch is a single GraphQL layer that pulls content from Markdown, a headless CMS, or REST/GraphQL APIs into the same query interface.
Bruno is an open-source API client and IDE designed as a lightweight alternative to tools like Postman. Its core differentiator is storing API collections directly on your filesystem using a plain text markup language called Bru, which enables collaboration via Git or any version control system. Bruno operates offline-only, with no plans for cloud synchronization, emphasizing data privacy by keeping all collection data on your device. It is available across Mac, Windows, and Linux via binary downloads and various package managers, and offers a CLI with Docker support for automated testing and CI/CD pipelines. While the majority of its features are free and open source, commercial versions are also available for additional capabilities.
Django REST Framework is a toolkit for adding a REST API layer on top of an existing Django project. It supplies serializers, viewsets, routers, and a web-based browsable API, so a Django app that already has models can expose them as JSON without you writing raw request-parsing and response-formatting code by hand.
YApi is a self-hosted, open-source platform (Apache-2.0) for managing API interface definitions, generating mock data, and running automated response tests for a whole development team.
Swagger Client is a JavaScript library maintained at swagger-api/swagger-js, published to npm as swagger-client, that loads and resolves Swagger 2.0 and OpenAPI 3.x documents so code can call the operations they define. It runs in Node.js 22+ and in current Chrome, Safari, Firefox, and Edge builds via each runtime's native fetch, and the README's compatibility table tracks five tagged releases, from 2.1.32 for Swagger 1.x up to 3.37.x for OpenAPI 3.2.0.
Apollo Client Devtools is a browser extension for Chrome, Firefox, and Opera (via the Chrome Web Store) that integrates directly into the browser's developer tools as an "Apollo" tab. It provides an embedded Apollo Studio Explorer to make queries against a GraphQL server using the application's network interface without extra configuration. Developers can inspect active queries, variables, and cached results, re-run individual queries and mutations, and visualize the Apollo Client cache, searching by field names or values. The extension actively supports the current minor release of Apollo Client and aims to support older 3.x versions, but does not offer support for 2.x. It appears automatically in development mode and can be enabled in production by passing `connectToDevTools: true` to the ApolloClient constructor or manually attaching the client instance to `window.__APOLLO_CLIENT__`.
Gatsby is a React framework that generates websites at build time, then lets individual pages opt into deferred or server-side rendering when static output isn't enough. It ships as an open-source, MIT-licensed monorepo of npm packages, and its main pitch is a single GraphQL layer that pulls content from Markdown, a headless CMS, or REST/GraphQL APIs into the same query interface.
Django REST Framework is a toolkit for adding a REST API layer on top of an existing Django project. It supplies serializers, viewsets, routers, and a web-based browsable API, so a Django app that already has models can expose them as JSON without you writing raw request-parsing and response-formatting code by hand.
Bruno is an open-source API client and IDE designed as a lightweight alternative to tools like Postman. Its core differentiator is storing API collections directly on your filesystem using a plain text markup language called Bru, which enables collaboration via Git or any version control system. Bruno operates offline-only, with no plans for cloud synchronization, emphasizing data privacy by keeping all collection data on your device. It is available across Mac, Windows, and Linux via binary downloads and various package managers, and offers a CLI with Docker support for automated testing and CI/CD pipelines. While the majority of its features are free and open source, commercial versions are also available for additional capabilities.
free-for.dev is a curated GitHub list of SaaS, PaaS, and IaaS offerings with free tiers, maintained by ripienaar and scoped to services infrastructure developers actually use: cloud providers, cloud management tooling, source code hosting, and APIs/data/ML services, among other categories. The repository has been built through pull requests, reviews, and ideas from the community.
Apollo Client Devtools is a browser extension for Chrome, Firefox, and Opera (via the Chrome Web Store) that integrates directly into the browser's developer tools as an "Apollo" tab. It provides an embedded Apollo Studio Explorer to make queries against a GraphQL server using the application's network interface without extra configuration. Developers can inspect active queries, variables, and cached results, re-run individual queries and mutations, and visualize the Apollo Client cache, searching by field names or values. The extension actively supports the current minor release of Apollo Client and aims to support older 3.x versions, but does not offer support for 2.x. It appears automatically in development mode and can be enabled in production by passing `connectToDevTools: true` to the ApolloClient constructor or manually attaching the client instance to `window.__APOLLO_CLIENT__`.
Swagger Client is a JavaScript library maintained at swagger-api/swagger-js, published to npm as swagger-client, that loads and resolves Swagger 2.0 and OpenAPI 3.x documents so code can call the operations they define. It runs in Node.js 22+ and in current Chrome, Safari, Firefox, and Edge builds via each runtime's native fetch, and the README's compatibility table tracks five tagged releases, from 2.1.32 for Swagger 1.x up to 3.37.x for OpenAPI 3.2.0.
Dear ImGui is an open-source C++ library at ocornut/imgui for building graphical interfaces inside your own application, described in its own README as bloat-free and renderer agnostic. It targets content-creation tools, visualization panels, and debug UI for game engines and real-time applications rather than end-user software, and ships with officially maintained backends for DirectX, OpenGL, Vulkan, Metal, WebGPU, and more.
JSON-Server is an open-source Node.js tool from typicode that generates a REST API from a single JSON file, with full CRUD routes, query-param filtering, sorting, pagination, and relationship embedding built in. The GitHub repository and the project is MIT licensed. The current README documents a v1 beta; a separate v0.17.4 branch remains the stable release.
The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.
Blazing fast, instant realtime GraphQL APIs on all your data with fine grained access control, also trigger webhooks on database events.
Swagger UI is a collection of HTML, JavaScript, and CSS assets that dynamically generate beautiful documentation from a Swagger-compliant API.
短信转发器——监控Android手机短信、来电、APP通知，并根据指定规则转发到其他手机：钉钉群自定义机器人、钉钉企业内机器人、企业微信群机器人、飞书机器人、企业微信应用消息、邮箱、bark、webhook、Telegram机器人、Server酱、PushPlus、手机短信等。包括主动控制服务端与客户端，让你轻松远程发短信、查短信、查通话、查话簿、查电量等。（V3.0 新增）PS.这个APK主要是学习与自用，如有BUG请提ISSUE，同时欢迎大家提PR指正
Saleor Core: the high performance, composable, headless commerce API.
Mobile Security Framework (MobSF) is an automated, all-in-one mobile application (Android/iOS/Windows) pen-testing, malware analysis and security assessment framework capable of performing static and dynamic analysis.
swagger-codegen contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI / Swagger definition.
Scalar is an open-source API platform: 🌐 Modern REST API Client 📖 Beautiful API References ✨ 1st-Class OpenAPI/Swagger Support
DataLoader is a generic utility to be used as part of your application's data fetching layer to provide a consistent API over various backends and reduce requests to those backends via batching and caching.
ShowDoc is a tool greatly applicable for an IT team to share documents online一个非常适合IT团队的在线API文档、技术文档工具
Offline documentation browser. Your personal reference library, searchable in an instant.
