A method of generating a mailer on demand by receiving data for an envelope and a matching document in a computer, placing data for the envelope and the document in a production queue, generating the envelope using the data, generating the document using the data, automatically verifying the correct generation and sequence of the envelope, automatically verifying the correct generation and sequence of the document, removing any envelope or document if the verification process returns a false condition for correct generation or sequence in order to maintain order integrity of the production queue and automatically regenerating the incorrectly generated or sequenced piece and all other corresponding piece(s) of the mailer, and matching a verified envelope with a matching verified document and creating the mailer.