Validation and multi-step forms
Required fields, email checks and error messages in Tessolo forms, and how to split a long form into multiple steps with human verification.
Required fields
Each field has a Required switch. A visitor can't submit without filling it in, and the form says which field is missing.
Be sparing. Every required field costs you some submissions. The honest test for each one: could we follow up without this? If yes, make it optional. A phone number you never call is not worth the people who abandon the form rather than give it.
Email fields
Set an Input's type to email and the value is checked for a plausible email address before submitting.
It catches typos like a missing @. It cannot tell you the address exists — only sending
something to it does that. If the address matters, an
auto-reply doubles as a check: the visitor notices
when it doesn't arrive.
An optional email field is only checked when the visitor typed something.
What the visitor sees
On submit, anything invalid is marked in place with a short message next to the field, and nothing is sent until it's fixed. Nobody loses what they typed.
Splitting a long form into steps
A Step block inside a Form breaks it into pages. Put fields into steps and visitors get a progress indicator with previous and next buttons — you don't place those yourself.
Worth doing when a form has more than about eight fields. Six fields on each of two steps feels much lighter than twelve at once, even though it's the same twelve.
On the canvas every step is expanded, so you can edit all of them. Only visitors see one at a time.
Steps are a way of presenting a form, not logic. There's no "if they picked A, show step 3". That would be a small programming language in a settings panel, and it isn't one we're going to put in front of people who came here to avoid programming.
The step titles come from the blocks, so name them for what the visitor is doing: "About you", "Your project", "How to reach you".
Human verification
If your site has it enabled, a verification widget appears on the published form to keep bots out. Nothing to configure per form. See spam protection and limits.