It actually started with XML. At the time there were not any decent options so I wrote my own and then made it a C extension. JSON can next since XML worked out so well. Basically JSON parsers were slow and I thought I could do better.

It started out as just a need for better performance than the standards but with golang I felt a full implementation of JSONPath would be of benefit to myself and others.

The real motivation though is the challenge and knowing people are using the code I write.