How do I get the Form POST data before it's stored on table

[VictorRayan]

I would like to create a project such as Login form where the user can send its data, then the form validate these data before storing them in some table and case there is some invalid data, on the same form display a message to the user, like a normal web page flow.

I would like to know how I can do this, and if possible without getting a billing plan.

[ScottWorld]

That is not possible with Airtable’s forms. You would need to use a tool like JotForm and then send your data to Airtable from there, either using JotForm’s native Airtable integration or using an advanced integration tool like Make.