Almost every useful feature on a modern website borrows data from somewhere else. The weather on a patio page, the map on a contact page, the check that stops a typo’d email address in a form: those usually come from free APIs, small services that hand your site a piece of information when it asks.
The trouble is finding them. There are thousands, and most lists are written for programmers. So I went through one of the biggest community lists, public-apis, and sorted it into plain English. It holds 1,969 APIs across 51 categories, and 930 of them need no key at all. This page is the map. The deeper guides for each category link from here as I write them.
What an API is, in plain English
An API is a doorway one computer program uses to ask another for something. Your website asks a weather service “what’s the forecast for Stow tomorrow?” and gets back a short, structured answer it can show on the page. Nobody copies and pastes anything, and the answer is always current.
You don’t need to be a programmer to benefit from one. Many website plugins and no-code tools are really just a friendly front end on top of an API. Knowing what’s out there helps you ask better questions when you’re planning a feature.
What free APIs can do for a small business site
A few everyday examples:
- Show the local forecast or a “patio’s open” note on a restaurant site.
- Fill in city and state automatically when someone types a ZIP code.
- Catch fake or mistyped email addresses before a contact form sends.
- Show public holidays so your hours banner is right on the Fourth of July.
- Make QR codes, charts, or PDFs on the fly.
- Pull in upcoming local events or game schedules.
If you’re curious how a site talks to your other tools more broadly, I wrote about that in connecting your website to your business tools.
How to read the directory
Each entry says whether you need a key. “No key needed” means you can try it right away. “Sign up for a key” means a free account first, and many of those have paid tiers once you grow. “Users connect their own account” means each person signs in with that service. The APIs come from the community-kept public-apis list, and the descriptions are mine. Services change, so check each one before you rely on it.
Before you build on a free API
Free is a great way to start, but it comes with trade-offs. Here’s what I check before I build anything on a free API:
- Read the terms. Some free APIs are for personal or non-commercial use only. If it will run on a business site, make sure that’s allowed.
- Check the limits. Free plans usually cap how many requests you can make per day or month. Know what happens when you hit the cap.
- Look for signs of life. Recent documentation updates, a status page, and a clear way to contact the people behind it are good signs.
- Keep your key private. If an API needs a key, it belongs on your server, not in code anyone can see in their browser.
- Have a plan B. Free services change or shut down. Build so you could swap in another provider without rebuilding everything.
The free API directory, by category
The number in brackets is how many APIs the list has in that category. Categories with a guide link have their full list, sorted and explained.
For business websites
- Weather (43): Forecasts, history, radar, UV and air quality. My guide: Free Weather APIs, Sorted and Explained.
- Geocoding (102): Turn addresses into map points and back, look up ZIP codes, maps, routing, and find where a website visitor is from their IP. My guide: Free Geocoding and Map APIs: Addresses, ZIP Codes, and Visitor Location.
- Events (4): Find concerts, games and local events (Ticketmaster, SeatGeek, Eventbrite, local trivia and open mics).
- Calendar (18): Public holidays by country and state, plus Google Calendar.
- Email (32): Validate email addresses, check domain email setup (SPF/DKIM/DMARC), spam-score a message, send email, or make throwaway test inboxes. My guide: Free Email and Phone Validation APIs, Explained.
- Phone (7): Check that a phone number is real and find its carrier. My guide: Free Email and Phone Validation APIs, Explained.
- Data Validation (14): Check that an address, VAT number or piece of text is real and clean (includes a profanity filter). My guide: Free Email and Phone Validation APIs, Explained.
- Business (38): Company lookups, email marketing, analytics, payments (Square), project boards and lead-finding tools.
- Social (54): Social network APIs for posting, login and data (Facebook, Instagram, LinkedIn, TikTok, X, plus multi-network posting tools).
- URL Shorteners (21): Short links, some with click tracking and QR codes.
- Photography (34): Stock photos, image compression and resizing, background removal, screenshots.
- Documents & Productivity (45): Make PDFs, convert files, read text from images (OCR), and connect to tools like Airtable, Notion and Asana.
- Shopping (21): Store and marketplace data (Best Buy, eBay, Etsy, WooCommerce).
- Authentication & Authorization (7): Ready-made login, passwordless sign-in and permission services.
- Security (54): Website and domain security scans, breached-password checks, bot and fraud detection.
- Anti-Malware (18): Check whether a link, domain, IP or file is known to be dangerous (phishing, malware, blacklists).
Food, health, and getting around
- Food & Drink (31): Nutrition facts, barcode food databases, recipes, grocery data, breweries and beer. My guide: Free Food and Nutrition APIs for Recipe and Diet Apps.
- Health (42): Nutrition databases, FDA data, clinical and medical references, COVID data.
- Sports & Fitness (56): Team and game stats and schedules, betting odds, workout and exercise data, Fitbit and Strava.
- Environment (25): Air quality, pollen, carbon footprint and energy data.
- Transportation (88): Public transit, flights, traffic, EV charging, routing, Uber, Tripadvisor ratings.
- Vehicle (14): Vehicle specs, recalls, VIN lookups and connected-car data.
- Tracking (11): Package tracking and habit tracking.
Data and research
- Government (115): Open government data: census, labor stats, federal spending, city open data, company registries.
- Open Data (63): Large public datasets: Wikipedia, Internet Archive, barcodes, business listings (Yelp), link previews.
- Finance (83): Stock prices, banking data, tax and financial filings.
- Currency Exchange (26): Currency conversion rates.
- Cryptocurrency (86): Crypto prices, exchanges and wallet data.
- Blockchain (16): Blockchain network data and tools.
- Jobs (29): Job listings and salary data.
- News (26): News headlines and articles.
- Science & Math (47): Space, math, physics and scientific data.
- Patent (4): Patent search.
- Books (26): Book catalogs, Bible and religious texts, library data.
- Dictionaries (16): Word definitions, synonyms and translations.
- Text Analysis (19): Language detection, translation, sentiment and text analysis.
- Machine Learning (42): AI services: text generation, image recognition, speech-to-text, content moderation.
For developers
- Development (193): Developer utilities: screenshots, QR codes, charts, push notifications, web scraping, domain lookups, test servers.
- Programming (5): Code-related data (for example, Codeforces, Hackerearth).
- Open Source Projects (11): Data about open source projects and packages.
- Continuous Integration (6): Build and test automation services for code.
- Cloud Storage & File Sharing (19): Upload, store and share files (Dropbox, Google Drive, Box, and simple file drops).
- Test Data (33): Fake names, addresses, users and products for testing.
Just for fun
- Animals (24): Pictures and facts about dogs, cats, birds and other animals. Mostly for fun or placeholder content.
- Anime (19): Anime and manga databases, quotes and pictures.
- Art & Design (27): Museum collections, icons, colors and design assets.
- Entertainment (18): Jokes, quotes, movie and TV trivia.
- Music (35): Song, artist and lyrics data (Spotify, Last.fm and others).
- Personality (26): Quotes, advice and fun personality content.
- Video (52): Movie, TV and video platform data (YouTube and others).
Other API directories worth bookmarking
- public-apis on GitHub: the community list this directory is built from.
- APIs.guru: technical descriptions of public APIs, useful once a developer is involved.
- RapidAPI: a marketplace where one account gives you access to many APIs. Lots are paid, so check the price on each.
Questions I hear a lot
Are free APIs really free?
Many are free up to a limit, then paid. Some are free forever for personal use but not for business use. Read the pricing and terms page before you build on one.
Do I need a developer to use an API?
For a custom feature, usually yes. But many plugins and no-code tools already use these APIs behind the scenes, so you may be able to get the feature without writing code.
Is it safe to use a free API on my website?
It can be, as long as keys stay on your server, you only send the data the service needs, and you have a fallback if it goes down.
What’s the difference between an API and a plugin?
A plugin is software installed on your site. An API is a service somewhere else that your site talks to. Plenty of plugins are wrappers around an API.
If you’d like a hand
Picking an API and wiring it into a website or small app safely is part of my apps and platforms work. If you have a feature in mind and aren’t sure it’s doable, tell me what you’re picturing and I’ll tell you honestly what it would take.