forms

Formsets handle multiple forms on one page. I use modelformset_factory for editing existing objects and inlineformset_factory for related objects. The extra parameter controls empty forms shown. I validate formsets with formset.is_valid() and save wit

Wizards are often over-engineered with client state machines. With Turbo Frames, I render each step inside a frame, and the “Next” button simply POSTs to update the record and then redirects to the next step URL. If validation fails, I re-render the s

After a successful inline create, I usually want to clear the form. You can replace the whole form partial, but sometimes you want to preserve other state (like which field was focused) and simply reset values. A clean Hotwire approach is a custom Tur

Hotwire forms feel “native” when invalid submissions keep you in context. Replace just the form frame with errors and keep the rest of the page intact. Return 422 so clients and caches behave correctly.

For nested forms, Stimulus can manage the DOM while Rails handles the final params. Use a hidden template + a unique timestamp key. This keeps the server-rendered form simple and avoids JS frameworks.

I use clean_<fieldname>() to validate individual fields and clean() to validate field combinations. Raising ValidationError shows the message to the user near the appropriate field. For cross-field validation (like 'end date must be after start