bgpstuff.net has been far more successful than I could imagine. I initially created it as a side project to learn how to create a website directly with Go. I also used gRPC between the front and backs ends. Since I created the first implementation it’s now served nearly 2 million requests.
Soon after the initial version, I added JSON support. The reason being that I wanted to create a RESTful API for users to query. I don’t have that much experience with REST so my implementation was not great. Various cracks in my code appeared dealing with the sheer amount of queries.