Free Public APIs That Need No API Key (2026)

Every developer needs quick APIs for prototyping, testing, or building tools. Here's a curated list of APIs that just work — no signup, no key, no BS.

Developer Tools

DevToolKit — 28 endpoints: SSL checker, DNS lookup, email validation, hash generator, UUID, QR codes, JWT decode, cron explainer

curl http://5.78.129.127/api/ssl/example.com
curl http://5.78.129.127/api/dns/lookup/example.com

httpbin.org — HTTP testing

curl https://httpbin.org/ip

JSONPlaceholder — Fake REST API for prototyping

curl https://jsonplaceholder.typicode.com/posts/1

Crypto & Finance

CoinGecko — Crypto prices and market data

curl "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd"

USD to Sats — Quick Bitcoin satoshi conversion

curl http://5.78.129.127/api/crypto/sats?usd=10

Security

Have I Been Pwned (Passwords) — Check password breach status using k-anonymity

curl https://api.pwnedpasswords.com/range/5BAA6

SSL/Headers Check — Audit any domain's security posture

curl http://5.78.129.127/api/headers/inspect?url=https://example.com

Data & Fun

wttr.in — Weather in your terminal

curl "wttr.in/Tokyo?format=j1"

REST Countries — Country info

curl "https://restcountries.com/v3.1/name/japan"

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Full interactive list with search: http://5.78.129.127/free-apis

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