`anna@gmail.com` and `anna@acme.com` may belong to the same person, and they behave differently in a list.

For B2B lead forms, a free-provider address often means a student or someone keeping the vendor at arm's length. A corporate address can be tied to a company, a size and a buying role. Verification differs too: big free providers answer SMTP checks in their own particular ways.

uChecker covers both sides: free email providers and corporate email on your own domain.