How to validate business email address in marketo form

There are quite a lot of similar threads already on the Community! (Also, by verifying, I am assuming you’d want to prevent form submissions from non-business email domains)

There are a couple of ways you can do this - 

1. Use Marketo’s OOTB form validation rule to enable blocking the domains in “Consumer Email Domain Blocklist“ list. This list has the free consumer email domains, you can view domains in the list here. You can also block specific domains from submitting Marketo forms by creating custom global form validation rules. Refer this documentation page.

2. Use a custom JS to prevent submission from a set of predefined  email domains. The authoritative  list of free consumer email domains is here. Ref - Sandy’s comment on a similar post here.

I hope this is helpful! Please let us know if you have questions. 😃