Rash is an extension to Hashie Rash subclasses Hashie::Mash to convert all keys in the hash to underscore. The purpose of this is when working w/ Java (or any other apis) that return hashes (including nested) that have camelCased keys You will now be able to access those keys through underscored key names (camelCase still available). WWW: https://github.com/tcocca/rash