IPLocate is a powerful IP geolocation API with 1,500 free requests per day. And for those free requests, you don't need an API key, so you can get started with one line of code.
Really easy to get started with, pre made library for Node was awesome
Fast response time, accurate data
Well such kind of service is not easy to build, because you need some really good data. I assume you take the RIPE information as basis. I'm honestly not satisfied with the result and have seen other service being more accurate than this one.
Lots of free requests
good response time
accuracy is below tolerance that it can be of use - it can't resolve cities in Germany