NOTICE: Taxpayers are strongly encouraged to visit the DRS website for answers to many questions. You may also email DRS at If contacting DRS by phone, please plan for wait times that may be longer than usual. See DRS FAQ's, which now include important information regarding Connecticut sales tax. Frequently Asked Questions

Software Developers Efile

Software developers are required to successfully complete the Connecticut Participant Acceptance Testing System (PATS) test for Legacy e-file and ATS testing for Modernized e-File (MeF). The purpose of PATS/ATS is to ensure that the software meets Connecticut specifications, the electronic returns have no validation or computation errors, and the returns can be transmitted in the correct format.

DRS is in the process of migrating to a NEW Software Developer’s site.  To access the NEW site you must register by clicking on this link, Register for the NEW Software Developer’s Site, and follow the instructions.

If you already registered and received your acknowledgement email from DRS you may click on this link, Software Developer’s SharePoint Site

Until you receive your registration acknowledgement from DRS you may access the OLD site by clicking on this link, Software Developers Website

  • For additional information regarding e-file, contact the DRS Electronic Filing help desk at 860-297-4713.