MailerSend

MailerSend offers email validation as part of its transactional and marketing email platform, giving you real-time verification for addresses entered in signup forms or imported lists. The API validates format, checks domain existence, and flags risky patterns so you can prevent bad data from entering your systems in the first place.

It's a natural fit if you're already using MailerSend for email delivery and want verification integrated into the same platform. The bulk list cleaning feature makes it straightforward to process existing databases without learning a new interface, and since verification lives alongside your sending tools, you can enforce validation rules as part of your delivery workflow.