Open-source apis software
2782 open-source libraries, tools and applications tagged apis, ranked by how closely apis is their primary purpose, then by adoption and maintenance health. Each entry links to a page with sources, use cases and when to choose or avoid it.
2782 products, primary matches first, then adoption-weighted; health v2 shown.
| Product | Health v2 | Stars | Maturity |
|---|---|---|---|
| OpenIddict OpenIddict is a flexible OAuth 2.0/OpenID Connect framework for .NET, providing server, client, and token validation stacks. It supports st… | 96 | 5257 | stable |
| su-kaka/gcli2api A self-hosted Python service that converts GeminiCLI and Antigravity into OpenAI-, Gemini-, and Claude-compatible API endpoints. It can be … | 63 | 5243 | active |
| typicode/jsonplaceholder JSONPlaceholder is a free online fake REST API for testing and prototyping, serving common resources like posts, comments, and users. It is… | 32 | 5239 | stable |
| AgnesAI-Labs/AgnesAI-Models Official gateway and model catalog for Agnes AI, providing OpenAI-compatible API access to multimodal foundation models covering text, imag… | 55 | 5192 | active |
| signalwire/freeswitch FreeSWITCH is an open-source software-defined telecom stack that turns commodity servers into a full telephony platform for voice, video, a… | 96 | 5191 | stable |
| MapsterMapper/Mapster Mapster is a fast, convention-based object-to-object mapping library for .NET/C#. It supports mapping to new or existing objects, queryable… | 99 | 5182 | active |
| NdoleStudio/httpsms httpSMS is a service that turns an Android phone into an SMS gateway, letting you send and receive SMS messages programmatically via a simp… | 91 | 5160 | active |
| Rack Rack is a minimal, modular Ruby library and specification that wraps HTTP requests and responses into a simple call, unifying the bridge be… | 81 | 5131 | stable |
| go-restful A Go package for building REST-style web services with explicit HTTP method routing and path parameter support. It provides configurable ro… | 67 | 5113 | stable |
| LoopBack LoopBack 4 is a highly extensible Node.js and TypeScript framework for building REST APIs and microservices, driven by OpenAPI specificatio… | 77 | 5101 | active |
| mislav/hub hub is a command-line tool that wraps git to add GitHub-specific features like cloning, creating repositories, forking, and submitting pull… | 23 | 22953 | maintenance |
| stoplightio/prism Prism is an open-source CLI tool that turns OpenAPI v2/v3 documents or Postman Collections into a fully functional HTTP mock server with dy… | 93 | 5043 | active |
| CrowCpp/Crow Crow is a fast, header-only C++ microframework for building HTTP and WebSocket web services, with Flask-style routing and type-safe handler… | 89 | 4997 | active |
| MockServer MockServer is an open-source HTTP(S) mock server and proxy for testing that can mock APIs, record and inspect live traffic, and inject fail… | 100 | 4994 | active |
| python-jsonschema/jsonschema A Python library implementing the JSON Schema specification for validating JSON data against schemas. It supports all major JSON Schema dra… | 79 | 4987 | stable |
| googlemaps/google-maps-services-python The official Python client library for Google Maps Platform Web Services, covering Directions, Distance Matrix, Elevation, Geocoding, Geolo… | 67 | 4978 | stable |
| protobuf-net protobuf-net is a contract-based serializer for .NET that writes data in Google's Protocol Buffers wire format using idiomatic .NET pattern… | 96 | 4972 | stable |
| slack-go/slack A Go client library covering most of the Slack Web API (api.slack.com) plus real-time messaging via WebSocket, Socket Mode, and the Events … | 95 | 4965 | active |
| Apache Dubbo Apache Dubbo-go is the official Go implementation of the Apache Dubbo microservice framework, providing high-performance RPC with service d… | 95 | 4964 | active |
| Swift Protobuf Apple's Swift Protobuf provides a protoc plugin for generating Swift code from .proto files plus the runtime library needed to use that gen… | 93 | 4963 | stable |
| Alpha Vantage Python Wrapper A Python wrapper library for the Alpha Vantage API providing access to stock, cryptocurrency, forex, fundamental, technical indicator, and … | 62 | 4926 | active |
| mailru/easyjson easy is a fast JSON serializer for Go that generates marshaler/unmarshaler code for structs via a CLI code generator, avoiding reflection. … | 64 | 4914 | stable |
| spring-cloud/spring-cloud-gateway Spring Cloud Gateway is an API gateway built on Spring Framework, Spring Boot, and Project Reactor. It provides routing, filtering, and tra… | 95 | 4907 | stable |
| ACI.dev ACI.dev is an open-source tool-calling platform that connects 600+ SaaS tools to AI agents and agentic IDEs via direct function calling or … | 59 | 4905 | active |
| aldinokemal/go-whatsapp-web-multidevice GoWA is a self-hosted WhatsApp REST API service written in Go, exposing WhatsApp multi-device messaging over HTTP with a web UI, webhooks, … | 94 | 4898 | active |
| Goravel Goravel is a full-featured, modular web application framework for Go, styled after Laravel so PHP developers can build Golang applications … | 87 | 4869 | active |
| imroc/req Req is a simple yet powerful Go HTTP client library with chainable APIs, supporting HTTP/1.1, HTTP/2, and HTTP/3. It offers built-in debugg… | 94 | 4866 | active |
| ZijianHe/koa-router koa-router is Express-style routing middleware for the Koa web framework, supporting named parameters, nested routers, and async/await. It … | 50 | 4811 | stable |
| Integuru-AI/Integuru Integuru is an AI agent that reverse-engineers platforms' internal APIs by analyzing browser network requests (HAR files) and building depe… | 59 | 4781 | active |
| tokio-rs/prost prost is a Protocol Buffers implementation for Rust that generates simple, idiomatic Rust types from proto2 and proto3 files. It supports s… | 79 | 4775 | stable |
| CLI Printing Press A Go-based CLI generator that studies official API docs, community CLIs, MCP servers, and undocumented web APIs to produce token-efficient,… | 77 | 4774 | active |
| graphql-go A GraphQL server library for Go focused on ease of use, with schema parsing, type-checked resolvers, and an HTTP relay handler. It supports… | 98 | 4754 | active |
| EasySwoole EasySwoole is a high-performance, persistent-memory PHP framework built on the Swoole extension, designed for building coroutine-based APIs… | 68 | 4753 | active |
| googleworkspace/md2googleslides A Node.js command-line tool that converts Markdown and HTML into Google Slides decks via the Google Slides API. It supports CommonMark/GFM … | 10 | 4727 | active |
| Strawberry GraphQL Strawberry is a developer-friendly GraphQL library for Python built on dataclasses and type hints. It lets you define GraphQL schemas with … | 92 | 4721 | active |
| Twikit Twikit is a free Python library that wraps Twitter's internal API, allowing posting, searching, and scraping tweets without an official API… | 57 | 4720 | active |
| webonyx/graphql-php A feature-complete PHP implementation of the GraphQL specification, based on the JavaScript reference implementation. It provides type syst… | 95 | 4715 | stable |
| xxnuo/MTranServer MTranServer is an offline machine translation server with very low resource usage and millisecond response times, requiring no GPU. It supp… | 60 | 4711 | active |
| discord-jda/JDA JDA (Java Discord API) is a Java library for building Discord bots, wrapping Discord's real-time WebSocket gateway and REST API behind an e… | 98 | 4691 | active |
| IBM/mcp-context-forge ContextForge is an open-source AI gateway, registry, and proxy from IBM that federates MCP, A2A, and REST/gRPC APIs behind a unified endpoi… | 86 | 4646 | active |
| prest/prest pRESTd is a production-ready Go service that exposes instant REST APIs (and a read-only MCP endpoint) on top of any existing or new Postgre… | 100 | 4624 | stable |
| mholt/json-to-go A tool that instantly converts JSON into Go type (struct) definitions, available as a browser-based web tool and a Node.js script. It is a … | 32 | 4621 | stable |
| Cerbos Cerbos is an open-core, language-agnostic policy decision point (PDP) that externalizes authorization from application code using context-a… | 94 | 4616 | stable |
| spec-first/connexion Connexion is a Python web framework for spec-first (API-first) development, where the API is described in an OpenAPI/Swagger specification … | 77 | 4613 | active |
| Knife4j Knife4j is an all-in-one enhancement solution for Swagger2 (OpenAPI2) and OpenAPI3 in the Java/Spring ecosystem, providing an improved API … | 48 | 4588 | active |
| apache/fory Apache Fory is a blazingly fast multi-language serialization framework supporting idiomatic domain objects, a reference-aware schema IDL, a… | 98 | 4568 | active |
| emissary-ingress/emissary Emissary-ingress is an open-source, Kubernetes-native API gateway, Layer 7 load balancer, and Kubernetes Ingress built on Envoy Proxy. It i… | 83 | 4521 | stable |
| Google Cloud Go Client Libraries The official Google Cloud Client Libraries for Go, providing idiomatic Go packages for accessing Google Cloud Platform services such as Sto… | 95 | 4520 | active |
| typestack/routing-controllers A TypeScript framework for building structured, declarative class-based controllers with decorators on top of Express or Koa. It handles ro… | 68 | 4506 | stable |
| uber-go/dig dig is a reflection-based dependency injection toolkit for Go that resolves object graphs at process startup. It is designed to power appli… | 36 | 4504 | stable |
| Judge0 Judge0 is an open-source, sandboxed online code execution system exposing a simple HTTP JSON API for compiling and running untrusted code i… | 68 | 4485 | active |
| tdlib/telegram-bot-api An open-source C++ server that implements the Telegram Bot API as an HTTP service, built on TDLib. It can be self-hosted to run bots agains… | 73 | 4474 | active |
| Agent Client Protocol The Agent Client Protocol (ACP) is an open protocol, with a Rust schema crate and JSON Schema artifacts, that standardizes communication be… | 82 | 4473 | active |
| spatie/laravel-query-builder A Laravel package that builds Eloquent queries from API request parameters, supporting filtering, sorting, field selection, and relationshi… | 100 | 4470 | stable |
| Cysharp/MagicOnion MagicOnion is a unified RPC and real-time communication framework for .NET and Unity, built on gRPC and MessagePack. It uses C# interfaces … | 93 | 4452 | active |
| danielgtaylor/huma Huma is a modern micro-framework for building HTTP REST/RPC APIs in Go, backed by OpenAPI 3.1 and JSON Schema. It is router-agnostic (bring… | 94 | 4449 | active |
| poem-web/poem Poem is a full-featured, easy-to-use web framework for Rust built on async/await, with crates for OpenAPI, gRPC, AWS Lambda, and MCP server… | 67 | 4445 | active |
| Salvo Salvo is a powerful yet simple async web framework for Rust, built on Hyper and Tokio. It offers tree-based routing, unified handler/middle… | 99 | 4440 | active |
| Wire Protocol Buffers Wire is Square's protocol buffer (protobuf) library with gRPC support for Kotlin, Java, Swift, and Android. It generates lightweight, idiom… | 76 | 4432 | active |
| rails/jbuilder Jbuilder is a Ruby gem providing a simple Builder-style DSL for declaring JSON structures, commonly used in Rails views via ..jbuilder temp… | 82 | 4421 | stable |
| Kinto/kinto Kinto is a minimalist self-hostable JSON document storage service with synchronisation and sharing capabilities, exposed over a REST HTTP A… | 100 | 4418 | active |
| tmenier/Flurl Flurl is a fluent URL builder and testable HTTP client library for .NET, available as a stand-alone URL builder (Flurl) or with HTTP featur… | 23 | 4402 | stable |
| Absinthe Absinthe is a complete, production-ready GraphQL implementation and toolkit for Elixir. It provides compile-time-verified schema macros, a … | 90 | 4398 | stable |
| open-webui/mcpo mcpo is a lightweight Python proxy that takes any MCP (Model Context Protocol) server command and exposes its tools as a standard OpenAPI-c… | 64 | 4385 | active |
| microsoft/RulesEngine A Microsoft-maintained .NET library for abstracting business rules and policies out of application code into externally stored, JSON-define… | 72 | 4350 | active |
| phpDocumentor/phpDocumentor phpDocumentor is the de-facto documentation generator for PHP projects, producing API documentation from source code and DocBlock comments.… | 85 | 4347 | stable |
| getsentry/responses A Python library for mocking out the `requests` HTTP library in tests. It lets you register fake responses with matching on method, URL, he… | 92 | 4342 | active |
| algorithmicsuperintelligence/optillm OptiLLM is an OpenAI API-compatible optimizing inference proxy that applies 20+ inference-time techniques (e.g., Mixture of Agents, MCTS, c… | 85 | 4307 | active |
| wechatpy/wechatpy wechatpy is a third-party Python SDK for the WeChat (微信) official platform ecosystem. It wraps APIs for official accounts, WeChat Pay, WeCo… | 57 | 4307 | active |
| HttpRunner HttpRunner (hrp) is an open-source, Go-based all-in-one testing framework for API testing (HTTP/HTTP2/WebSocket/RPC), load testing, and mul… | 44 | 4302 | active |
| ssut/py-googletrans An unofficial free Python library that wraps Google Translate's Ajax API for text translation and language detection. It supports async usa… | 62 | 4284 | active |
| google-gemini/gemini-skills A collection of agent skills (context packages) for the Gemini API, SDKs, and model interactions, installable into AI coding assistants via… | 60 | 4279 | active |
| OWASP Dependency-Track OWASP Dependency-Track is an open-source component analysis platform that ingests CycloneDX SBOMs to continuously identify vulnerabilities,… | 99 | 4269 | active |
| rhysd/actionlint actionlint is a static checker for GitHub Actions workflow files, written in Go. It validates syntax, type-checks ${{ }} expressions, verif… | 78 | 4265 | active |
| praw-dev/praw PRAW is a Python package that wraps Reddit's API, providing simple, rule-compliant access to Reddit data and actions. It handles OAuth auth… | 95 | 4259 | stable |
| UsefulSoftwareCo/executor Executor is an open-source integration layer and MCP gateway for AI agents, letting you configure MCP servers, OpenAPI specs, GraphQL APIs,… | 77 | 4162 | active |
| ericc-ch/copilot-api A reverse-engineered proxy that exposes the GitHub Copilot API as OpenAI and Anthropic compatible endpoints, letting any OpenAI/Anthropic-c… | 44 | 4148 | active |
| typhoeus/typhoeus Typhoeus is a Ruby library that wraps libcurl to make fast, reliable HTTP requests, including running many requests in parallel via its Hyd… | 61 | 4134 | stable |
| juhaku/utoipa Utoipa is a Rust library that auto-generates OpenAPI documentation at compile time using proc macros, treating a code-first approach as a f… | 99 | 4132 | stable |
| Microsoft Authentication Library (MSAL) Microsoft Authentication Library (MSAL) for JavaScript enables client-side and server-side JS apps to authenticate users with Microsoft Ent… | 95 | 4126 | active |
| acacode/swagger-typescript-api A TypeScript tool that generates typed API clients for Fetch or Axios from OpenAPI 3.0/2.0 specifications in JSON or YAML. It can be used a… | 92 | 4124 | active |
| msgspec/msgspec msgspec is a fast Python serialization and validation library supporting JSON, MessagePack, YAML, and TOML. It combines high-performance en… | 80 | 4122 | stable |
| weavejester/compojure Compojure is a concise routing library for the Ring web ecosystem in Clojure, letting developers compose web applications from small, indep… | 48 | 4114 | stable |
| Connect Connect is a family of slim libraries (Go, TypeScript, Swift, Kotlin, Dart, Python) for building browser- and gRPC-compatible HTTP APIs fro… | 99 | 4110 | stable |
| Pyramid Pyramid is a small, fast, open-source Python web framework from the Pylons Project built on WSGI. It scales from single-file hello-world ap… | 72 | 4102 | stable |
| jetty/jetty.project Eclipse Jetty is a lightweight, highly scalable Java web server and servlet container supporting HTTP/1, HTTP/2, HTTP/3, and WebSocket. It … | 99 | 4099 | stable |
| swagger-api/swagger-codegen Swagger Codegen is a template-driven code generator that parses OpenAPI/Swagger definitions to produce API client SDKs, server stubs, and d… | 95 | 17789 | maintenance |
| knowm/XChange XChange is a Java library providing a simple, consistent API for interacting with 60+ Bitcoin and other cryptocurrency exchanges. It suppor… | 77 | 4089 | active |
| DailyHot API DailyHotApi is a TypeScript-based API service that aggregates trending/hot list data from many Chinese platforms (Bilibili, Weibo, Zhihu, D… | 53 | 4088 | active |
| urllib3/urllib3 urllib3 is a user-friendly, powerful HTTP client library for Python with thread-safe connection pooling, SSL/TLS verification, retries, and… | 93 | 4068 | stable |
| OAuth2 Server A Node.js module for implementing a fully RFC 6749/6750 compliant OAuth2 server/provider, framework-agnostic with official wrappers for Exp… | 23 | 4063 | active |
| httpie/desktop HTTPie Desktop is a cross-platform graphical API testing client for REST, GraphQL, and HTTP APIs, distributed via this repository as releas… | 32 | 4047 | active |
| koxudaxi/datamodel-code-generator A Python CLI tool that generates type-safe Python data models (Pydantic v2, dataclasses, TypedDict, msgspec.Struct) from schema definitions… | 96 | 4042 | active |
| apollographql/apollo-ios Apollo iOS is a strongly-typed, caching GraphQL client for Swift, supporting iOS, macOS, watchOS, tvOS, and visionOS. It provides code gene… | 94 | 4037 | stable |
| googleapis/python-genai The official Google Gen AI Python SDK for integrating Google's generative models (Gemini Developer API and Gemini Enterprise Agent Platform… | 85 | 4035 | active |
| slackapi/python-slack-sdk The official Slack Developer Kit for Python, providing packages for calling Slack Web API methods, sending messages via webhooks, receiving… | 96 | 4016 | active |
| cloudflare/capnweb Cap'n Web is a JavaScript/TypeScript-native, schema-free object-capability RPC library from Cloudflare, created by the Cap'n Proto author. … | 83 | 4015 | active |
| badrisnarayanan/antigravity-claude-proxy A Node.js proxy server that exposes Antigravity's Cloud Code Claude and Gemini models behind an Anthropic-compatible Messages API. It trans… | 74 | 4004 | active |
| Kubernetes The official Python client library for the Kubernetes API, generated from the OpenAPI spec and maintained by SIG API Machinery. It supports… | 100 | 4001 | active |
| BenedictKing/ccx CCX is a self-hosted AI API proxy and protocol translation gateway written in Go that unifies access to Claude, OpenAI Chat/Images/Embeddin… | 72 | 3992 | active |