Plan availability - Onlyform API

The public API enforces the same plan capabilities as the dashboard.

Capability	Free	Pro / eligible paid plan
Standard question and content blocks	Yes	Yes
Signature blocks	No	Yes
Gate blocks	No	Yes
File-upload blocks	No	Yes, when file uploads are enabled
Payment blocks	No	Yes, when payments are enabled
Standard theme tokens	Yes	Yes
Custom CSS	No	Yes
Show Onlyform branding	Yes	Yes
Remove Onlyform branding	No	Yes, when branding removal is enabled
Completion redirect	No	Yes, when redirects are enabled
Questions per form	Plan limit	Plan limit
Responses per form	Plan limit	Plan limit

A restricted write returns:

{
  "type": "authorization_error",
  "code": "PLAN_RESTRICTION",
  "message": "Your plan does not support this change."
}

The API permits removing a paid feature from a form after a downgrade. It does not permit adding or changing that feature until the required capability is available again.