Yojson is an optimized parsing and printing library for the JSON format. It
addresses a few shortcomings of json-wheel including 2x speedup, polymorphic
variants and optional syntax for tuples and variants.

ydump is a pretty-printing command-line program provided with the yojson
package.

The program atdgen can be used to derive OCaml-JSON serializers and
deserializers from type definitions.