AnAPI can be thought of as an instruction manual for communication between multiple software apparatuses. For example, an API may be used for database communication between web applications. By extracting the implementation and relinquishing data into objects, an API simplifies programming.

A collective list of free APIs

• UpdatedNov 4, 2025
• Python

Vim-fork focused on extensibility and usability

• UpdatedDec 17, 2025
• Vim Script

FastAPI framework, high performance, easy to learn, fast to code, ready for production

• UpdatedDec 17, 2025
• Python

Open-Source API Development Ecosystem •https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia

• UpdatedDec 16, 2025
• TypeScript

🚀 Strapi is the leading open-source headless CMS. It’s 100% JavaScript/TypeScript, fully customizable, and developer-first.

• UpdatedDec 17, 2025
• TypeScript

Dear ImGui: Bloat-free Graphical User interface for C++ with minimal dependencies

• UpdatedDec 15, 2025
• C++

A lightning-fast search engine API bringing AI-powered hybrid search to your sites and applications.

• UpdatedDec 17, 2025
• Rust

A cryptocurrency trading API with more than 100 exchanges in JavaScript / TypeScript / Python / C# / PHP / Go

• UpdatedDec 17, 2025
• Python

🤖 The free, Open Source alternative to OpenAI, Claude and others. Self-hosted and local-first. Drop-in replacement for OpenAI, running on consumer-grade hardware. No GPU required. Runs gguf, transformers, diffusers and many more. Features: Generate Text, MCP, Audio, Video, Images, Voice Cloning, Distributed, P2P and decentralized inference

• UpdatedDec 17, 2025
• Go

🧙‍♀️ Move Fast and Break Nothing. End-to-end typesafe APIs made easy.

• UpdatedDec 17, 2025
• TypeScript

Opiniated RAG for integrating GenAI in your apps 🧠 Focus on your product rather than the RAG. Easy integration in existing products with customisation! Any LLM: GPT4, Groq, Llama. Any Vectorstore: PGVector, Faiss. Any Files. Anyway you want.

• UpdatedJul 9, 2025
• Python

The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.

• UpdatedDec 17, 2025
• TypeScript

🥧 HTTPie CLI — modern, user-friendly command-line HTTP client for the API era. JSON support, colors, sessions, downloads, plugins & more.

• UpdatedDec 17, 2024
• Python

Beautiful static documentation for your API

• UpdatedJun 13, 2024
• SCSS

Free ChatGPT&DeepSeek API Key，免费ChatGPT&DeepSeek API。免费接入DeepSeek API和GPT4 API，支持 gpt | deepseek | claude | gemini | grok 等排名靠前的常用大模型。

• UpdatedDec 15, 2025
• Python

The flexible backend for all your projects 🐰 Turn your DB into a headless CMS, admin panels, or apps with a custom UI, instant APIs, auth & more.

• UpdatedDec 17, 2025
• TypeScript

Blazing fast, instant realtime GraphQL APIs on all your data with fine grained access control, also trigger webhooks on database events.

• UpdatedDec 15, 2025
• TypeScript

网易云音乐 Node.js API service

• UpdatedFeb 28, 2024

Web APIs for Django. 🎸

• UpdatedDec 15, 2025
• Python

LLM API 管理 & 分发系统，支持 OpenAI、Azure、Anthropic Claude、Google Gemini、DeepSeek、字节豆包、ChatGLM、文心一言、讯飞星火、通义千问、360 智脑、腾讯混元等主流模型，统一 API 适配，可用于 key 管理与二次分发。单可执行文件，提供 Docker 镜像，一键部署，开箱即用。LLM API management & key redistribution system, unifying multiple providers under a single API. Single binary, Docker-ready, with an English UI.

• UpdatedNov 20, 2025
• JavaScript