Ruby-psych is a YAML parser and emitter. Psych leverages libyaml for its YAML parsing and emitting capabilities. In addition to wrapping libyaml, Psych also knows how to serialize and de-serialize most Ruby objects to and from the YAML format.

Psych has been included with the main Ruby implementation since 1.9.2, and is the default YAML parser from 1.9.3 and beyond.