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20 Free APIs You Didn't Know Existed (Bookmark This)

#ai #webdev #javascriptlibraries #beginners

Most of the backend code I've deleted this year wasn't deleted because it was bad. It was deleted because the thing it did was already a free API, and I just didn't know.

That's the quiet tax on building alone: not the stuff that's hard, but the stuff that's solved — solved by someone who put it behind a public URL and a free tier, and never crossed your feed. You write a currency-conversion endpoint. You scrape a weather site. You build a little service to turn a postal code into a city, and you maintain it forever, because you never found out that five people already did and gave it away.

So here are twenty I actually reach for. Not the famous ones everybody lists — not Stripe, not OpenWeather, not the GitHub API you already know. The ones that quietly save you an afternoon and a server. I've grouped them by the problem they solve, put a real example call next to each, and — because the one thing worse than not knowing an API exists is getting burned by its fine print — I've been honest about which ones need a key, which rate-limit you, and which ask for attribution.

A fair warning up front: "free" has edges. A free tier is a gift, not a guarantee. Several of these are run by one person or a small nonprofit, and the fastest way to kill a free API is to hammer it like it's yours. Read the one-line caveat next to each before you put it in production. With that said:

Data you'd otherwise pay for, scrape, or maintain forever

1. Open-Meteo — weather, with no API key at all.
The one that feels illegal. Full forecast, historical, and air-quality data, no sign-up, no key, free for non-commercial use.

GET https://api.open-meteo.com/v1/forecast?latitude=23.81&longitude=90.41&current=temperature_2m
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That's the whole integration. No dashboard, no billing page, no "your trial ends in 14 days."

2. REST Countries — every country, one call.
Flags, capitals, currencies, calling codes, languages, borders, population. Every dropdown of countries you've ever hand-typed could have been this. Free, no key.

GET https://restcountries.com/v3.1/name/bangladesh
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3. Frankfurter — currency exchange rates from the European Central Bank.
Open-source, no key, backed by official ECB reference rates. If you've been paying a FX API for a side project, stop.

GET https://api.frankfurter.app/latest?from=USD&to=BDT,EUR
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Caveat: ECB publishes once per working day, so this is daily rates, not live tick-by-tick. Perfect for 95% of apps; wrong for an actual trading desk.

4. Nager.Date — public holidays for any country, any year.
"Is next Tuesday a holiday in Germany?" is a shockingly annoying thing to compute, and this answers it for free, no key, for most of the world.

GET https://date.nager.at/api/v3/PublicHolidays/2026/BD
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5. Open Library — book metadata by ISBN.
Covers, titles, authors, publish dates, from the Internet Archive. If you're building anything with books, this is your catalogue. Free, no key.

GET https://openlibrary.org/isbn/9780140328721.json
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Location & identity, without the geo-SaaS bill

6. Nominatim (OpenStreetMap) — free geocoding, both directions.
Address → coordinates and back. The thing every maps SDK charges you for after a few thousand calls.

GET https://nominatim.openstreetmap.org/search?q=Dhaka&format=json
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Caveat — and this one's load-bearing: Nominatim's public server is max 1 request/second, requires a real User-Agent, and asks for attribution. It's run for the community, not for your bulk job. Respect it or self-host; abuse it and you're blocked, fairly.

7. Zippopotam.us — postal code to place, 60+ countries.
Postal/ZIP code in, city + state + coordinates out. No key.

GET https://api.zippopotam.us/BD/1207
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8. ip-api.com — IP geolocation with no key.
Country, region, city, ISP, lat/long from an IP. Free for non-commercial use at 45 requests/minute, no sign-up.

GET http://ip-api.com/json/8.8.8.8
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Caveat: the free endpoint is HTTP and non-commercial only; HTTPS and commercial use are the paid tier. Fine for internal tooling and demos, read the terms before it ships to paying users.

9. Sunrise-Sunset — solar times for any coordinate.
Sunrise, sunset, dawn, dusk, solar noon, day length. For anything that should behave differently at night, this beats guessing. Free, no key.

GET https://api.sunrise-sunset.org/json?lat=23.81&lng=90.41
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Content, media & metadata

10. Free Dictionary API — definitions, phonetics, audio.
dictionaryapi.dev. Definitions, parts of speech, example sentences, even pronunciation audio. No key, no cost.

GET https://api.dictionaryapi.dev/api/v2/entries/en/serendipity
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11. Wikipedia REST API — clean article summaries.
Skip scraping Wikipedia. There's a real API that hands you a clean summary, thumbnail, and extract for any title. Free; just attribute.

GET https://en.wikipedia.org/api/rest_v1/page/summary/Dhaka
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12. Unsplash & Pexels — genuinely free stock photos, programmatically.
Both have real APIs with generous free tiers (Unsplash: 50 requests/hour on the demo tier; Pexels: 200/hour). High-quality images for placeholders, hero sections, or user-facing search — without a stock-photo invoice.

GET https://api.pexels.com/v1/search?query=mountains   (header: Authorization: <key>)
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Caveat: both need a free API key and ask you to credit the photographer. Unsplash's demo tier is for building; you apply for production limits.

13. goQR (api.qrserver.com) — QR codes from a URL.
No SDK, no npm package, no key. The image is the endpoint — drop it straight into an <img src>.

https://api.qrserver.com/v1/create-qr-code/?size=300x300&data=https://xenition.com
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14. Microlink — turn any URL into a rich preview.
Give it a link, get back the title, description, OG image, logo — even a screenshot. This is how you build link previews without writing a single scraper.

GET https://api.microlink.io/?url=https://dev.to
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Caveat: the keyless free tier is rate-limited (around 50 requests/day). Enough to prototype; you sign up for more.

Dev plumbing — prototyping, testing & demos

15. JSONPlaceholder — a fake REST API that's always up.
Posts, comments, users, to-dos — real-shaped JSON for wiring up a frontend before the backend exists. The localhost:3001 mock server you keep rebuilding, already hosted. Free, no key.

GET https://jsonplaceholder.typicode.com/posts/1
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16. Hacker News API — the whole site, as JSON.
Stories, comments, users, live updates, straight from Firebase. No key. Great for building a reader, a dashboard, or just a realistic data source with actual text in it.

GET https://hacker-news.firebaseio.com/v0/topstories.json
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17. Open Food Facts — product data by barcode.
Scan a barcode, get ingredients, nutrition, allergens, images. A community food database the size of a commercial one, free and open, no key.

GET https://world.openfoodfacts.org/api/v2/product/737628064502.json
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18. CoinGecko — crypto prices without an account.
Prices, market caps, historical charts for thousands of coins. The free "demo" tier works with no key for basic calls.

GET https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd
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Caveat: the keyless path is rate-limited (roughly 30 calls/minute) and CoinGecko has been tightening it — grab a free demo key if you're doing anything real.

19. Agify / Genderize / Nationalize — predict age, gender, nationality from a name.
Three sibling APIs, same team. Feed in "Michael," get back a predicted age, likely gender, or probable countries. The best "wow, it guessed" demo you can build in one fetch. Free up to 100 names/day, no key.

GET https://api.agify.io?name=michael
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A real caveat worth saying out loud: these are statistical guesses from name datasets. Fun for a demo, genuinely risky if you use them to make decisions about real people. Don't gate anything that matters on them.

20. Numbers API & Advice Slip — the fun that fills a demo.
numbersapi.com gives you a trivia fact about any number; Advice Slip hands you a random piece of advice. Neither needs a key. When you need something in the empty state of a prototype that isn't lorem ipsum, these are it.

GET http://numbersapi.com/42
GET https://api.adviceslip.com/advice
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The thing the list doesn't tell you

Here's the part nobody puts in these roundups, and it's the whole game: knowing the API exists was never the bottleneck. You can bookmark all twenty and still ship nothing. The gap between "oh neat, a free weather API" and a working feature is reading the docs, matching the auth, shaping the response into your UI, and handling the call that fails at 2am — and that gap is where side projects quietly die.

That gap is the reason I keep this list at all. Over the last year I stopped treating each integration as a project and started treating it as a sentence: "when someone enters a city, show them the forecast." Say the outcome, wire the one endpoint that delivers it, move on. The apps that shipped were the ones where I refused to rebuild what twenty strangers had already given away for free.

That's also the gap we built Xenition to sit in — our AI workspace, a Flutter app on iOS and Android. You describe the thing you want — "an app that turns a postal code into the local weather and a map" — and it drafts the app with the free endpoints already wired in, so the integration is a conversation instead of an afternoon. The list above is the raw material. The skill is spending none of your day on the part that was already solved.

Bookmark the twenty. Then go build the one feature you actually opened the laptop for.

Top comments (1)

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alexcodebytes profile image
Oleksandr •

This is genuinely useful — especially the honest caveats. Most "free API" lists skip the fine print and then your production app gets a 429 at 2 AM.

One I'd add that's saved me days: Frankfurter's sibling exchangerate.host is nice but the real gem is open.er-api.com/v6/latest/USD — free, no key, 160+ currencies, refreshed daily. Not ECB-official, but fine for non-financial use cases.

Also, on #2 (REST Countries): they've had outages this year because the project is one maintainer and the traffic is huge. Worth mentioning as a "have a fallback" case — I've seen projects break because they treated a single volunteer API as critical infrastructure.