1. I think you can just throw an error, and instead of swapping your filled-in form, you make a validation error appear below the form, e.g. 2. So far in my ex

1. I think you can just throw an error, and instead of swapping your filled-in form, you make a validation error appear below the form, e.g. 2. So far in my experience a rest API for my own front end has been pretty specific, so I'd want to add a separate API anyway for that purpose.