How long is data stored for on your servers? Can a purge be requested ad hoc?

Please note that we do not delete submission data from form. Its just that if you downgrade your account to free plan and since free account has submission storage limit of 500 submission, all over quota submissions will get deleted automatically once your account is downgraded to free plan.

You can anytime delete the submissions data from your form. The following guide should help you how to delete submission data from form: https://www.jotform.com/help/377-How-to-Delete-Form-Submission-Data

Hope this helps.

Do get back to us if you have any questions.