Top 23 API Open-Source Projects

1. public-apis

   1 414 350,930 3.5 Python

   A collective list of free APIs

   

   Project mention: 🔥 Hidden Gems on GitHub That Every Developer (IT/Non-IT) Needs to Explore | dev.to | 2025-05-30

   📊 6. Public APIs 📍 https://github.com/public-apis/public-apis  Why it's awesome:  A massive list of free APIs for development, testing, and integration. You can use them to build apps, dashboards, or even just explore new ideas. ✅ Best For: App devs, students, startup founders  🧠 Ideas: Weather app, crypto tracker, quote bot, anime finder

2. InfluxDB

   www.influxdata.com featured

   InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

   

3. neovim

   2 1,431 90,252 10.0 Vim Script

   Vim-fork focused on extensibility and usability

   

   Project mention: When Life Gives You Time Off Install and Configure Neovim | dev.to | 2025-06-04

   So I headed over to the Neovim GitHub like any lost soul would and followed the official install steps:

4. fastapi

   3 549 86,038 9.8 Python

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

   

   Project mention: Getting Started with FastAPI: A Beginner’s Guide Using Python 🐍 | dev.to | 2025-06-01

   Official FastAPI Docs

5. Hoppscotch

   4 238 72,156 9.7 TypeScript

   Open source API development ecosystem.

   

   Project mention: These 20 Awesome API Clients Will Change How You Work with APIs | dev.to | 2025-06-11

   Hoppscotch is a modern, sleek, and fast browser-based API client designed for speed and simplicity. Originally inspired by Postman, it's now a full ecosystem supporting REST, GraphQL, WebSocket, and more.

6. Strapi

   5 504 66,977 9.9 TypeScript

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

   

   Project mention: SOLVED: REST API and Content Manager returning different IDs for entries | dev.to | 2025-05-29

   This case is not rare, you can find another case here: https://github.com/strapi/strapi/issues/21967

7. imgui

   6 375 66,091 9.8 C++

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

   

   Project mention: Ask HN: What are good high information density UIs (screenshots, apps, sites) | news.ycombinator.com | 2025-05-08

   I find the imgui UIs to be very high density (https://github.com/ocornut/imgui and the gallery issues) See for example the tracy profiler: https://github.com/wolfpld/tracy. It seems the game dev community has pretty powerful tools to understand and interrogate their work.

8. quivr

   7 24 37,970 9.5 Python

   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.

   

   Project mention: Ask HN: Local RAG with private knowledge base | news.ycombinator.com | 2024-10-29

9. SaaSHub

   www.saashub.com featured

   SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

   

10. trpc

    8 38 37,564 9.8 TypeScript

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

    

    Project mention: How to Secure TypeScript Applications...?? | dev.to | 2025-01-01

    Leverage libraries like tRPC or GraphQL with TypeScript to ensure type safety across the stack:

11. ccxt

    9 76 36,883 10.0 Python

    A JavaScript / TypeScript / Python / C# / PHP / Go cryptocurrency trading API with support for more than 100 bitcoin/altcoin exchanges

    

    Project mention: Revolutionize Your Crypto Trading with CCXT! | dev.to | 2025-05-07

    View the Project on GitHub

12. insomnia

    10 248 36,534 9.8 TypeScript

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

    

    Project mention: Postman is logging all your secrets and environment variables | news.ycombinator.com | 2025-05-16

13. slate

    11 21 36,148 3.4 SCSS

    Beautiful static documentation for your API

    

14. httpie

    12 133 35,841 6.6 Python

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

    

    Project mention: 6 Game-Changing Postman Alternatives That Will Revolutionize Your API Development in 2025 | dev.to | 2025-05-09

    For developers who prefer terminal-based workflows, HTTPie offers a more user-friendly alternative to curl while maintaining the efficiency of command-line tools. Its intuitive syntax and colorized output make API testing from the terminal more accessible and productive.

15. LocalAI

    13 90 33,172 9.9 Go

    :robot: 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 models architectures. Features: Generate Text, Audio, Video, Images, Voice Cloning, Distributed, P2P inference

    

    Project mention: Nvidia on NixOS WSL – Ollama up 24/7 on your gaming PC | news.ycombinator.com | 2025-04-10

    If you're going to run Ollama in Windows anyway, why not use the native build? And if you want to use WSL, then I'd sugggest using something like LocalAI which gives you a lot more control and support for additional formats (GGML, GGUF, GPTQ, ONNX, etc).

    https://github.com/mudler/LocalAI

16. Hasura

    14 236 31,569 9.9 TypeScript

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

    

    Project mention: My personal favorite MCP server which has became part of my life | dev.to | 2025-05-27

    GitHub: github.com/hasura/graphql-engine

17. SWR

    15 258 31,566 7.4 TypeScript

    React Hooks for Data Fetching

    

    Project mention: React’s Four Horsemen of the Frontendpocalypse | dev.to | 2025-05-24

18. Directus

    16 227 30,844 9.9 TypeScript

    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.

    

    Project mention: Directus.js (JavaScript SDK) – The official client for Directus APIs | dev.to | 2025-06-11

    If you're working with Directus, the open-source headless CMS and data platform, then Directus.js is your new best friend.

19. Medusa

    17 225 29,433 10.0 TypeScript

    The world's most flexible commerce platform.

    

    Project mention: Ask HN: Who is hiring? (January 2025) | news.ycombinator.com | 2025-01-02

20. django-rest-framework

    18 209 29,198 8.4 Python

    Web APIs for Django. 🎸

    

    Project mention: Why Django REST Framework doesn't show your custom validation error messages (and what to do about it) | dev.to | 2025-05-21

    The GitHub Discussion: link

21. one-api

    19 1 25,635 9.7 JavaScript

    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.

    

22. postgrest

    20 112 25,387 9.5 Haskell

    REST API for any Postgres database

    

    Project mention: Generate an OpenAPI From Your Database | dev.to | 2024-12-27

    This is especially helpful because Supabase uses PostegREST under the hood, which does not support OpenAPI 3.x. Note that some Postgres specific features like enums are not converted to JSON Schema enums as Sequelize doesn't expose that information.

23. openapi-generator

    21 254 23,956 9.9 Java

    OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

    

    Project mention: How To Introduce a New API Quickly Using Micronaut | dev.to | 2025-05-28

    The beta version was able to generate the expected Quote model object, but I ran into issues trying to generate an interface or abstract class that my controllers could extend. So I decided to create an issue in the openapi-generator library (link for those who are interested in the details) and pivot toward another approach.

24. api-guidelines

    22 18 23,032 4.8

    Microsoft REST API Guidelines

    

    Project mention: Common Mistakes in RESTful API Design | dev.to | 2025-03-25

    According to Microsoft's API design guidelines, excessive nesting makes APIs brittle and difficult to evolve. The second approach provides multiple ways to access the same data depending on the consumer's needs, improving flexibility without sacrificing clarity.

25. API-Security-Checklist

    23 4 22,854 4.2

    Checklist of the most important security countermeasures when designing, testing, and releasing your API

    

26. SaaSHub

    www.saashub.com featured

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    

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Index

Sponsored

InfluxDB – Built for High-Performance Time Series Workloads

InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

www.influxdata.com