<@UC01FS1C3> yes - you can use the cause of the Le...

# http4k

[dave]

@Riku yes - you can use the cause of the LensFailure to determine what kind of failure it was. in the case of missing parameters, you're going to have to rely on extracting out relevant bit of the (Jackson) message, but for custom validations, you've got other options. Personally I wouldn't make non-nullable fields nullable for this.