binlist.net — how a Fuerteventura holiday side-project became iinlist.com
In 2013, sitting on a balcony in Playitas, Fuerteventura, I built binlist.net as my first ever Go project — a free HTTP API for looking up the issuer of a credit card from its first six digits. It hit 1 million queries/day by 2015. Thirteen years later it's still free, and its commercial sibling iinlist.com is the one we run the business on.