List of free ip-address stuff for developerππ½
If you're looking for all programming tools around ip-address (not just free). Check this page List of ip-address Programming Tools

IPinfo.io
We're the trusted source for IP address information, handling 40 billion IP geolocation API requests per month for over 1,000 businesses and 100,000+ developers
Tag: ip-address
Geolocation 50k requests / month