One Open Source Project a Day (No. 213): public-apis — The 474k-Star Definitive Free API List

Introduction

"Whatever data you need, someone has almost certainly already organized it here."

This is the 213th article in the "One Open Source Project a Day" series. Today's project is public-apis.

Every developer has hit this scenario: you want to add a feature — real-time weather, currency exchange rates, random quotes, IP geolocation — and spend half a day hunting for "where is there a free API I can use," sorting out which ones need registration, which have rate limits, which support CORS…

public-apis exists precisely to solve that problem. A community-maintained list of free APIs: 1,400+ APIs, 50+ categories, each entry annotated with authentication method, HTTPS support, and CORS policy.

474k Stars, GitHub's top three by star count, MIT license.

What You Will Learn

• The complete categorization system (50+ categories, representative APIs in each)
• How to quickly find the API type you need
• Auth methods and usage constraint explanations across API types

Prerequisites

• Understanding of REST API basics
• Knowing what CORS, HTTPS, and API Key authentication are

Project Background

What It Is

public-apis is a pure documentation repository. The core is one very large table in README.md — each row is a usable public API, each column is key metadata:

CORS = Yes means the API can be called directly from the browser without a backend proxy — hugely important for frontend developers.

Project Stats

• ⭐ GitHub Stars: 474,000+ (top 3 on GitHub)
• 🍴 Forks: 52,400+
• 📄 License: MIT
• 📝 API count: 1,400+
• 🗂️ Categories: 50+
• 📅 Active maintenance: community contributions, updated weekly

Complete Category List

All categories with representative APIs, listed alphabetically.

🐾 Animals

Animal photos, facts, species data

🎌 Anime

Anime databases, images, quotes

🛡️ Anti-Malware

IP/domain/URL reputation, malware analysis

🎨 Art & Design

Museum collections, icons, color palettes, image generation

🔐 Authentication & Authorization

Login, OTP, access control

⛓️ Blockchain

On-chain data, smart contracts, DEX

📚 Books

Book data, poetry, religious texts

💼 Business

Company info, marketing, payments, procurement

📅 Calendar

Public holidays, religious calendars, working day queries

☁️ Cloud Storage & File Sharing

File upload, sharing, storage

⚙️ Continuous Integration

CI/CD platform APIs

💰 Cryptocurrency

Real-time/historical prices, DEX, on-chain data

💱 Currency Exchange

Real-time/historical exchange rates, conversion

✅ Data Validation

Address verification, phone numbers, VAT numbers

🛠️ Development

Screenshots, QR codes, IP lookup, code execution, web scraping

The largest category in the list — 100+ APIs. Grouped by sub-function:

IP & Networking

Screenshots & Web

QR Codes & Barcodes

Code Execution

Web Scraping

Dev Utilities

📖 Dictionaries

Definitions, synonyms, pronunciation

📄 Documents & Productivity

PDF generation, file conversion, project management

📧 Email

Email validation, disposable inboxes, sending services

🎭 Entertainment

Jokes, memes, quotes, horoscopes

🌍 Environment

Air quality, carbon emissions, renewable energy

🎟️ Events

Concerts, ticketing, venues

💹 Finance

Stocks, funds, macroeconomics, SEC filings

🍔 Food & Drink

Nutrition data, recipes, food products

🎮 Games & Comics

Game databases, esports, card games, comics

🗺️ Geocoding

Coordinate conversion, address search, mapping services

🏛️ Government

US/EU/global government open data

🏥 Health

Medical data, disease statistics, drugs

💼 Jobs

Job search, remote work, government positions

🤖 Machine Learning

AI models, image recognition, NLP

🎵 Music

Music catalogs, lyrics, concert info

📰 News

Global news aggregation, historical archives

📊 Open Data

General datasets, knowledge bases, city data

📋 Patent

Patents and intellectual property

💬 Personality

Inspirational quotes, advice, affirmations

📱 Phone

Phone number validation and lookup

📷 Photography

Photo libraries, placeholder images, image optimization

💻 Programming

Competitive programming, code execution

🔬 Science & Math

Space, astronomy, earthquakes, academic research

🔒 Security

Vulnerabilities, threat intelligence, identity

🛍️ Shopping

E-commerce platforms, product data

🌐 Social

Major social platform APIs

🏆 Sports & Fitness

All sports data, live scores

🧪 Test Data

Fake data, placeholders, random users

📝 Text Analysis

NLP, translation, sentiment analysis

📦 Tracking

Package and shipment tracking

✈️ Transportation

Flights, public transit, real-time schedules

🔗 URL Shorteners

Link shortening and tracking

🚗 Vehicle

Vehicle info, VIN decoding, safety ratings

🎬 Video

Movie/TV databases, streaming info

🌤️ Weather

Real-time/historical weather, forecasts, air quality

Deep Dive

How to Find the API You Need

public-apis offers three main discovery methods:

Method 1: Browse the README

Open the GitHub repo, jump to the relevant category in the table of contents, browse alphabetically.

Method 2: Keyword search

Press t on the repo page to enter file search, or search directly:

# Search in browser address bar
https://github.com/public-apis/public-apis/search?q=weather

Method 3: Use companion tools

The community has built several searchable interfaces on top of public-apis:

https://publicapis.dev          # Searchable web UI
https://api.publicapis.org      # REST API form of public-apis

The REST API form supports filtering by category, auth requirement, and CORS:

# Get all APIs requiring no auth and supporting CORS
curl "https://api.publicapis.org/entries?auth=null&cors=yes"
 
# Get APIs by category
curl "https://api.publicapis.org/entries?category=weather"
 
# Get a random API
curl "https://api.publicapis.org/random"

Understanding the Auth Field

The Auth field has three values that directly determine integration cost:

Prototyping/learning: prioritize Auth = No.
Production projects: apiKey is the norm; most provide free tiers.
Need to act on behalf of users: only then reach for OAuth (e.g., reading a user's Google Calendar).

Why CORS Matters

For frontend developers, CORS = Yes means the API can be called directly from the browser — no backend proxy needed.

// CORS = Yes: call directly from the browser
const response = await fetch('https://api.chucknorris.io/jokes/random');
const joke = await response.json();
 
// CORS = No: requires a backend proxy
// Browser → your backend server → target API

Project Links & Resources

Official Resources

• 🌟 GitHub: https://github.com/public-apis/public-apis
• 📄 License: MIT
• 🔍 Searchable UI: publicapis.dev
• 🤝 Contributing: CONTRIBUTING.md

Related Resources

• awesome-public-datasets — similar project focused on downloadable datasets (not APIs)
• rapidapi.com/hub — commercial API marketplace (includes paid APIs)

Summary

Key Takeaways

1. 474k Stars represents real developer need: every developer occasionally needs "data of some type without building the service" — this repo compresses that process to seconds
2. 50+ categories, 1,400+ entries: from animal photos to financial data, AI models to public transit — almost no gaps
3. Auth / HTTPS / CORS are the three critical columns: these three tell you the integration cost and use context
4. CORS = Yes is the frontend developer's quick filter: direct browser call, no proxy — the first choice for rapid prototyping

Who This Is For

• Frontend developers: quickly find data sources callable directly from the browser (filter: CORS=Yes, Auth=No)
• Beginners learning API development: a treasure chest of practice data sources — from cat photos to weather forecasts, every type is covered
• Hackathon participants: 48 hours to find the data your project needs
• Full-stack developers: integrate existing APIs rather than reinventing the wheel
• Technical content creators: source material for API tutorials and demo projects

One-Line Verdict

public-apis' value isn't in how many entries it has — it's that it permanently answers the question "I need some kind of data, where do I find it?" in a single place.

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