How to allow a user to fill out a form only once?

I have a form where a lead can fill out:

  • Name
  • Email
  • Phone

User is someone whose Email AND Phone are unique (I don’t have him/her in my Unbounce database).

Question: How to allow a user to fill out a form only once?
I don’t wanna use cookies only because if the user uses a different device to just deleted his cookies he/she can register again and that is not OK. Therefore I prefer “checking the uniques” by comparing data from Unbounce database.

1 Like

Hey Lukáš,

Hmm… that’s a good question! The only workaround that I’m aware of for preventing duplicate leads is this one but it does use cookies. One other option would be to add additional validation rules to your form, this can help prevent people from submitting false information – you can learn a bit more about this here.

If you’re open to using some custom code, let me know, there may be some more technical community members I can tag to see if they have anything in their toolkit.

All the best,


1 Like

@Luxqs -

What’s the broader use case? The Unbounce “database” is of relatively limited value for things like that. We typically do our work work elsewhere – say, zapping leads to Airtable. Unbounce builds a dirty database. That’s not a pejorative, but it’s more of a source of data than a place to manipulate and use it.

If you’re open to using some custom code.
Yes please

1 Like

We need optimize our PPC campaigns and its difficult to do it if one can one lead register multiple times coz even if you have set one conversion per cookie not always work. Therefore is not possible edit PPC in real time. And if the duplicity is not constant, is hard to check if we are in limits with CPA.
In our case we are will to pay agency X € per unique lead, Agency Fee = X - Ads spent

1 Like

If it’s me, I’d handle this externally. The formulas available in Google Sheets or Airtable (both of which can easily accept leads from Unbounce) will let you de-dupe, count, divide … whatever you need. No custom code required :slight_smile:


to be sure, you are saying that if I will use G Sheet or Airtable I will be able to allow users to fill the form only once?

1 Like

Good one! Keep sharing it👍

It wouldn’t prevent the fillout, but it would allow you to easily “check the uniques” without getting complicated. We very rarely use the Unbounce lead database as a system of record; rather, we instantly send every lead to a system purpose-built for data storage and analysis.