Hi and welcome
You could use a custom type for this:
JSONTime = ROM::Types::String.constructor { |time|
time.strftime('%Y-%m-%dT%H:%M:%S.%L%z')
}
# then in relation schema:
schema(infer: true) do
attribute :your_time_col, Types::Time, read: JSONTime
end
Notice that this assumes that input values are sent as time objects, if you want to pass strings and have them coerced to time, you need to use another custom type.
Hope this helps.