Browse 500+ free public APIs organized by category. Weather, finance, AI, social media, maps, and more — find the perfect API for your next project.
Every side project starts with the same question: where do I get the data? You have the frontend sketched out, the database schema planned, maybe even the deployment pipeline ready. Then you spend three hours Googling "free weather API" and end up on a Stack Overflow answer from 2019 that links to an API that no longer exists.
I've been there more times than I'd like to admit. And every time, the problem isn't that free public APIs don't exist — there are hundreds of them. The problem is finding the right one, knowing whether it's still maintained, understanding the rate limits, and figuring out if "free" actually means free or "free for 7 days."
That's why we built a curated API directory with over 505 free and freemium public APIs, organized by category, with details on authentication, CORS support, rate limits, and available SDKs. This post walks through the major categories, what you can build with each, and the practical details that documentation pages tend to bury.
The API economy isn't slowing down. If anything, it's accelerating. According to industry reports, over 90% of developers use third-party APIs regularly. The reason is straightforward: building everything from scratch is expensive, slow, and usually unnecessary.
Need real-time currency exchange rates? There's an API for that. Want to add AI-powered text generation to your app? API. Geocode an address into coordinates? API. Translate text into 100 languages? You get the idea.
The challenge isn't availability — it's curation. There are thousands of public APIs out there, and the quality varies wildly. Some have excellent documentation and generous free tiers. Others have misleading pricing pages, restrictive rate limits, or authentication flows that require a PhD to implement.
That's the gap our API directory fills. Every API is categorized, tagged with its auth method and pricing model, and includes direct links to documentation. You can search, filter by category, and even save favorites for quick access later.
The finance category is one of the richest in our directory. Whether you're building a budgeting app, a stock tracker, a crypto dashboard, or a payment integration, there's a free public API for it.
What you can build:
The key players here include payment processing APIs, stock market data providers, cryptocurrency exchanges, and currency conversion services. Most offer generous free tiers — thousands of requests per month — which is more than enough for side projects and MVPs.
Pro tip: Financial APIs often have different rate limits for real-time vs. historical data. If your app can tolerate a 15-minute delay on stock prices, you'll usually get significantly higher request limits on the free tier.
Browse all finance APIs in the directory.
This is the category that's exploded in the last two years. AI/ML APIs let you add capabilities that would take months to build from scratch: natural language processing, image recognition, text generation, sentiment analysis, speech-to-text, and more.
What you can build:
The free tiers in this category tend to be more restrictive than others — AI inference is expensive to run. But many providers offer enough free credits to prototype, test, and even run small-scale production apps.
Pro tip: Batch your AI API requests when possible. Instead of sending one text at a time for sentiment analysis, send arrays. Most providers charge per request, not per item in the request, so batching can dramatically reduce your costs.
Explore AI/ML APIs in the directory.
Geo APIs are the backbone of any location-aware application. From geocoding addresses to calculating driving distances to rendering interactive maps, this category covers it all.
What you can build:
The important nuance with maps APIs is that "free" often means "free up to a threshold." Map tile rendering is bandwidth-intensive, so most providers give you a monthly quota. For development and low-traffic apps, these quotas are generous. For production apps with thousands of daily users, you'll likely need a paid plan.
Pro tip: Cache geocoding results aggressively. If a user searches for "New York, NY" once, store the coordinates locally. Geocoding the same address repeatedly is the fastest way to burn through your free tier.
Find geolocation and maps APIs in the directory.
Social and communication APIs let you integrate with platforms where your users already spend their time. Send emails, process webhooks from messaging platforms, pull social media profiles, or build notification systems.
What you can build:
Authentication is the main complexity here. Most social APIs use OAuth 2.0, which means implementing a redirect-based flow. It's not difficult, but it adds steps to your onboarding process. Plan for it early in your architecture.
The data category is deliberately broad. It includes APIs for open government data, scientific datasets, reference data (countries, currencies, time zones), and general-purpose data services like IP geolocation and DNS lookup.
What you can build:
These tend to be the most generous with free tiers because the data itself is often publicly available. The API is just a convenient, structured way to access it.
Pro tip: Many data APIs return more fields than you need. Always specify the fields you want in the request (if the API supports it) to reduce response size and parsing time.
Media APIs cover image processing, video platforms, music services, game data, and content delivery. If you're building something visual or interactive, this is where you'll spend most of your time.
What you can build:
Rate limits in this category vary enormously. Image processing APIs might give you 100 free transformations per month. Content delivery APIs might give you 10GB of free bandwidth. Read the fine print carefully.
Cloud APIs let you programmatically manage infrastructure, storage, compute, and deployment pipelines. While the major cloud providers charge for usage, many offer substantial free tiers.
What you can build:
E-commerce APIs power product searches, price comparisons, shipping calculators, and marketplace integrations. IoT APIs connect to smart home devices, industrial sensors, weather stations, and more. Both categories are smaller but growing fast.
Browse the full API directory to explore all 12 categories, including health and developer tools.
Finding the right API is step one. Using it properly is step two. Here are the lessons I've learned the hard way.
Every free API has rate limits. Some are generous (1,000 requests per minute). Some are not (10 requests per second). Either way, you should implement client-side rate limiting — not because the API won't enforce its own limits, but because hitting those limits returns errors that break your app.
Akousa// Simple rate limiter with a token bucket
const rateLimiter = {
tokens: 10,
maxTokens: 10,
refillRate: 1, // tokens per second
lastRefill: Date.now(),
async waitForToken() {
this.refill();
if (this.tokens <= 0) {
const waitTime = 1000 / this.refillRate;
await new Promise((r) => setTimeout(r, waitTime));
this.refill();
}
this.tokens--;
},
refill() {
const now = Date.now();
const elapsed = (now - this.lastRefill) / 1000;
this.tokens = Math.min(this.maxTokens, this.tokens + elapsed * this.refillRate);
this.lastRefill = now;
},
};Free APIs use four common auth methods:
The most common mistake? Hardcoding API keys in frontend JavaScript. Use environment variables and proxy requests through your backend. Always.
APIs go down. Networks fail. Rate limits get hit. Your code needs to handle all of this gracefully.
async function fetchWithRetry(url: string, options: RequestInit, retries = 3): Promise<Response> {
for (let i = 0; i < retries; i++) {
try {
const response = await fetch(url, options);
if (response.status === 429) {
// Rate limited — wait and retry
const retryAfter = response.headers.get("Retry-After");
const delay = retryAfter ? parseInt(retryAfter) * 1000 : Math.pow(2, i) * 1000;
await new Promise((r) => setTimeout(r, delay));
continue;
}
if (!response.ok) {
throw new Error(`API error: ${response.status}`);
}
return response;
} catch (error) {
if (i === retries - 1) throw error;
await new Promise((r) => setTimeout(r, Math.pow(2, i) * 1000));
}
}
throw new Error("Max retries exceeded");
}If an API returns data that doesn't change every second — and most data doesn't — cache it. In-memory caching, Redis, browser localStorage, HTTP cache headers — use whatever fits your architecture. Your users get faster responses, you stay within rate limits, and the API provider doesn't have to handle unnecessary load.
This isn't exciting advice, but it's important. Some "free" APIs restrict commercial use. Others require attribution. Some prohibit storing data longer than 24 hours. A few minutes reading the ToS can save you from rewriting your entire data layer six months into a project.
Beyond the public API directory, we also maintain a Developer API Portal with 77 endpoints that you can use directly. These cover a wide range of utility functions — text processing, data conversion, encoding/decoding, and more — all documented with request/response examples.
The portal is designed for developers who need quick, reliable utility endpoints without signing up for yet another service.
Our API directory is built for developers who value their time. Here's what makes it different from a static list:
With over 505 APIs across finance, AI/ML, cloud, communication, social, data, geolocation, media, developer tools, e-commerce, health, and IoT categories, there's a strong chance we have what you're looking for.
The best API is the one that solves your specific problem with the least friction. Sometimes that's a massive platform with enterprise features. Sometimes it's a tiny open-source API that does exactly one thing well.
Stop Googling "free API list 2026" and opening ten tabs of outdated blog posts. Browse the full API directory, filter by what you need, save your favorites, and start building something.
The data is out there. The APIs are free. The only thing missing is your next project.