Tired of writing complementary parseJSON/toJSON, peek/poke or Binary get/put functions?

codec provides easy bidirectional serialization of plain Haskell records in any Applicative context. All you need to do is provide a de/serializer for every record field in any order you like, and you get a de/serializer for the whole structure. The type system ensures that you provide every record exactly once. It also includes a library for general record construction in an Applicative context, of which creating codecs is just one application.

JSON:

data User = User
  { username :: Text
  , userEmail :: Text
  , userLanguages :: [ Text ]
  , userReferrer :: Maybe User
  } deriving Show

genFields ''User

userCodec :: JSONCodec User
userCodec = obj "user object" $
  User
    $>> f_username      >-< "user"
    >>> f_userEmail     >-< "email"
    >>> f_userLanguages >-< "languages"
    >>> f_userReferrer  >-< opt "referrer"

instance FromJSON User where
  parseJSON = parseVal userCodec

instance ToJSON User where
  toJSON = produceVal userCodec