It used to be that lenders mailed out verifications to employers, banks, mortgage companies, and so on, in order to verify the data supplied by borrowers. Nowadays, things move faster.  "Alternate documentation" has become more widely used.

Alternate documentation means that underwriting answers can be obtained with information supplied directly from the borrower instead of waiting around for verifications to come back in the mail.

The following page lists the items you will most likely need to speed the processing of your home loan.  Items may differ according to whether your loan is a confoming (Fannie Mae or Freddie Mac), non-conforming (jumbo) loan, government loan, or a portfolio loan.

Verifications are still mailed out, but usually as part of quality control procedures.