Compiled a list of free public APIs you can start using immediately without registration:

Quick hits:

# Weather
curl "wttr.in/London?format=j1"

# IP info
curl https://ipapi.co/json/

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

# Random cat image
curl "https://api.thecatapi.com/v1/images/search"

# Password breach check
curl https://api.pwnedpasswords.com/range/5BAA6

Full list (15+ APIs, all with curl examples): http://5.78.129.127/free-apis

Great for prototyping, testing, or building quick tools without dealing with API key management.

What free APIs do you use regularly?