Modernized e-File (MeF) user guides and publications


General information and technical guidance for electronic return originators, software developers and transmitters who participate in Modernized e-File (MeF) is provided below.

General information

SSL certificates

Updated on Aug. 17, 2023: These are effective from Aug. 22, 2023.


User guides

Application-To-Application (A2A) Toolkit

The A2A MeF Software Development Kit (SDK) Toolkit provides software tools and documentation making it easier to build the A2A Client Application for transmitters and states. The toolkit will make it much easier to set up the service requests you need to develop to access the MeF system.

The A2A Toolkit is available to those transmitters and states interested in using the Modernized e-File (MeF) system to send or receive returns. If you are interested in receiving the toolkit, please send an e-mail to the MeF Mailbox to request a copy. Please put A2A Toolkit in the subject line.

If you are using Strong Authentication in your transmissions you must purchase Strong Authentication Certificates. Information on the Strong Authentication Certificates and where they can be purchased can be found at the following sites:

It will take between 7 to 14 days for a digital certificate to be issued after you have notarized your paper work and submitted it to the company.

It is imperative that affected contractors keep their digital certificates current. An expired digital certificate will delay the ability to submit.

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