FreeAPI.watch

15 Free APIs Perfect for Hackathon Projects

 ·  guide

Tested, no-key-required where possible, working in 2026. Pick from this list and start coding in minutes.

These 15 APIs are all actively monitored on FreeAPI.watch, working as of May 2026, and require no credit card. I've prioritised no-key APIs where possible — the fewer environment variables you need to manage at 2am, the better.

Grouped by category with a one-line integration example for each. All curl examples work verbatim.

Weather

  • Open-Meteo — 10,000 calls/day, no key. Best free weather API, period. `curl 'https://api.open-meteo.com/v1/forecast?latitude=51.5&longitude=-0.12&current=temperature_2m,weathercode'`
  • NOAA National Weather Service — unlimited, US only, no key. Official government data, solid uptime. `curl https://api.weather.gov/points/40.71,-74.00` (returns forecast URL for that location)
  • MET Norway Locationforecast — unlimited, no key, set User-Agent. Global coverage from Norwegian Met Institute. `curl -H 'User-Agent: HackathonApp/1.0' 'https://api.met.no/weatherapi/locationforecast/2.0/compact?lat=51.5&lon=-0.12'`

Finance & Currency

  • Frankfurter — unlimited, no key, ECB data. `curl https://api.frankfurter.app/latest` returns all major currency rates vs EUR. For a specific conversion: `curl 'https://api.frankfurter.app/latest?from=USD&to=EUR,GBP'`
  • ECB Rates — unlimited, no key. The raw XML source Frankfurter uses. `curl https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml`

Cryptocurrency

  • CoinGecko — 10–30 calls/min, no key (Demo). `curl 'https://api.coingecko.com/api/v3/simple/price?ids=bitcoin,ethereum&vs_currencies=usd'`
  • Coinpaprika — 25,000 calls/month, no key. `curl https://api.coinpaprika.com/v1/tickers/btc-bitcoin`
  • Binance Public — 1,200 req/min, no key. Real-time price: `curl 'https://api.binance.com/api/v3/ticker/price?symbol=BTCUSDT'`
  • Mempool.space — unlimited, no key. Bitcoin fee estimates: `curl https://mempool.space/api/v1/fees/recommended`

News & Content

  • Hacker News API — unlimited, no key. Top story IDs: `curl https://hacker-news.firebaseio.com/v0/topstories.json`. Single item: `curl https://hacker-news.firebaseio.com/v0/item/1234.json`
  • Wikipedia REST API — unlimited, no key, set User-Agent. Article summary: `curl -H 'User-Agent: HackathonApp/1.0' 'https://en.wikipedia.org/api/rest_v1/page/summary/Python_(programming_language)'`
  • DEV Community API — 30 calls/30s, no key for reads. Latest articles: `curl 'https://dev.to/api/articles?per_page=10&tag=javascript'`
  • Spaceflight News — unlimited, no key. `curl 'https://api.spaceflightnewsapi.net/v4/articles/?limit=5'`

Geocoding & Location

  • Nominatim — 1 req/sec, no key, set User-Agent. `curl -H 'User-Agent: HackathonApp/1.0' 'https://nominatim.openstreetmap.org/search?q=Times+Square&format=json&limit=1'`
  • ip-api.com — 45 req/min, no key (HTTP only). Lookup caller's IP: `curl http://ip-api.com/json` — useful for auto-detecting user location

Putting It Together: A Weather + Location Stack

For a hackathon weather app: use ip-api.com to get the user's lat/lng from their IP (no user input needed), then feed those coordinates directly to Open-Meteo for a forecast. Total setup time: under 5 minutes, zero environment variables.

See /no-key for the complete list of no-key APIs on FreeAPI.watch, and /best-free-apis-2026 for top picks per category with live status.

Frequently Asked Questions

What if I need an API not on this list?

Check /no-key for all no-key APIs we track, or /category/[name] for category-specific rankings. If you find an API that works well, suggest it via /contact. During a hackathon specifically, if a required API has a free tier but needs a key, sign up for the key first — most free key signups process in under 2 minutes.

How fast can I integrate these?

The no-key APIs on this list (Open-Meteo, Frankfurter, Hacker News, Nominatim, etc.) take under 5 minutes to integrate at the prototype level — one fetch() call, no environment variables required. Key-based APIs (CoinGecko, OpenWeatherMap) take 5–10 minutes including signup. All code snippets in this article are copy-paste ready.

Can I use them after the hackathon?

Yes — all APIs on this list are in regular production use by indie developers. The no-key APIs (Open-Meteo, Frankfurter, Nominatim) have no usage terms that restrict post-hackathon production use. Key-based APIs have terms you should review before going live, but the free tiers are generally available for personal and small-scale commercial use.

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