What are some alternatives?
When comparing ipstack and IP-API.com, you can also consider the following products
ipapi - Web analytics with IP address lookup and location API
ipgeolocation.io - Free IP Geolocation API and Accurate GeoIP Lookup Location Database
IP2Location - IP2Location is a leading provider of IP intelligence service.
ipdata.co - Get the Geolocation, Organisation, Currency, Timezone, Calling Code, Flag, Proxy, Tor and Threat intelligence data from any IPv4 or IPv6 address.
WIPmania - WIPmania provides a number of free products and services based on WorldIP geolocation database.
Ipregistry - Ipregistry is a fast, reliable IP geolocation and threat data API. People use Ipregistry to personalize content, analyze traffic, target ads, block countries but also to prevent abuse by detecting Proxy and Tor users, known spammers and bad bots.