All participants in the NYC program must comply with the procedures, requirements, and specifications as detailed in IRS Publication 3112: IRS e-File Application and Participation and IRS Publication 4164: Modernized e-File Guide for Software Developers and Transmitters.
Software Developer's Guide
Download TY2011 Guide
Electronic Return Originator's Guide
Download TY2011 Guide
NYC-Specific Schemas
Download TY2011 Schemas (Draft v3.0)
Download TY2011 Schemas (Draft v3.1)
Embedded TY2011 Generic Schedules
Attached TY2011 XML Schedules Business Rules
Download TY2011 Business Rules
2011 PDF Naming Conventions Error Codes
Error Categories and Messages (1/9/12) Test Packages
2011 GCT Test Package (v4.0 2/13/12)
2011 BCT Test Package (v1.0 11/28/11)
2011 UBTI Test Package (v2.0 2/13/12)
2011 UBTP Test Package (v3.0 2/13/12)
Other Links
Business Tax Services
Frequently Asked Questions (FAQs)
Email Business Tax e-File (BTeF) | 
2011 Information for Software Developers
