Invalid emails being accepted by Webflow form

Hey there,

It’s a single field email sign-up form and at the moment it’s allowing non-emails e.g. “test@test” to be submitted which then flags as a possible error in Zapier and Klaviyo.

Other forum posts say that in HTML5, this is a valid email entry, but in practice that kind of email isn’t useful – is there a way of making it a requirement to have a valid domain ending on the email before it can be submitted e.g. “” ?

Another forum post linked to this article about validation – <input type="email"> - HTML: HyperText Markup Language | MDN

For my use-case this part of the article would be sufficient:

  1. A single properly-formed e-mail address. This doesn’t necessarily mean the e-mail address exists, but it is at least formatted correctly. In simple terms, this means username@domain or username@domain.tld. There’s more to it than that, of course; see Validation for a regular expression that matches the e-mail address validation algorithm.

Can anyone shed any light on how to add the code into Webflow to make this level of email validation happen?

Here is my site Read-Only: (Webflow - Sequence)


You can test the regex I use here if you like;

Here’s how to validate your own email field.

In the designer, select your Email Input element, and add a custom attribute.
Name the attribute pattern, and paste in this value…


I’ve seen a lot of requests for this, so here’s a cloneable;

And more details on the approach;


This is a thing of beauty, thank you for sharing – have added to the live-site here

Ha ha yes the HTML5 specification team got a lot of things right.