Free APIs for side projects — 7 that work with no credit card

The most common snag on a first project isn't code — it's data. You want to build something live, but where do you get weather, images, a list of countries? Good news: plenty of services hand over data for free, and half of them need no signup or key at all. Here are seven you can actually build a first project on tonight. Ordered from "easiest" to "a bit more involved."

1. Open-Meteo — weather with no key

What it is: a weather forecast by coordinates. No API key, no signup — just hit the URL and get JSON back.

When to reach for it: a weather dashboard, an "umbrella today?" widget, a homepage block. The perfect first API — nothing to configure.

The catch: data is by coordinates (lat/long), not city name. Turning a name into coordinates means a separate lookup.

2. REST Countries — everything about countries, no key

What it is: flags, capitals, currencies, languages, population for any country. No key and almost no limits.

When to reach for it: a flag quiz, a currency converter, a country picker in a signup form.

The catch: it's reference data that rarely changes — for a "live" app it's just a reliable lookup, nothing more.

3. JSONPlaceholder — fake data for a prototype

What it is: a mock REST API with posts, users, comments. You use it not for the data but to practice: learn to fetch data, render lists, do pagination.

When to reach for it: when you're building the UI but have no real backend yet. Plug it in and the list fills up — now you have something to show.

The catch: the data is fake and doesn't persist. Submit a post and it "kind of" gets created — but not really.

4. Random User — ready-made fake users

What it is: a generator of realistic users — name, email, avatar, address. No key.

When to reach for it: filling a mockup with a list of people, a test feed, avatar placeholders. So the UI doesn't look empty in a demo.

The catch: same as #3 — it's decoration, not real people. Perfect for a presentation; in production, swap it for real data.

5. Google Gemini — AI in your project, with a generous free tier

What it is: access to an AI model straight from code — text generation, image understanding, Q&A. The free tier is generous (on the order of a few thousand requests a day); a key is required.

When to reach for it: a chatbot, auto-tagging notes, photo analysis — anything that needs "smart" processing. It's your bridge to agents.

The catch: there's a per-minute and per-day request limit — fine for a side project, not for production load. And the key must never be exposed in front-end code.

6. TheCatAPI / Dog API — animal pictures

What it is: an endless stream of cat and dog photos. The simplest API there is: "ask — get an image URL."

When to reach for it: the classic first project, "press a button — show a cat." Sounds trivial, but it's the best trainer: request → response → image on screen, the whole loop in 20 lines.

The catch: none. That's the point — a teaching API with no pain.

7. OpenRouteService — maps and routes

What it is: routing, distances, geocoding (address → coordinates). Up to 2,000 requests a day free; a key is required.

When to reach for it: "how long from A to B," a map with pins, delivery. A more serious step — this one has signup and a key.

The catch: the API is rich and the documentation is hefty — budget time to learn it. But it covers almost everything "maps."

How do I even connect an API to my project?

In short: you send a request to the service's URL and get data back (usually as JSON) to show in your app. Stuck? Ask your AI editor: "connect Open-Meteo and show the weather for Moscow." It'll write the request code for you — and you can study how it works. More in the vibe-coder tools roundup.

What if an API runs out of its free quota?

Rare for a side project — limits run into the thousands of requests. If you do hit it: cache responses (don't hit the service a hundred times for the same thing), and move to a paid tier as the project grows. But early on the free tier is plenty — no need to pay in advance; better to validate the idea with real people first.