IRIS Application-to-Application (A2A) is the system-to-system channel for bulk filing of information returns using Extensible Markup Language (XML). It is designed for large volume filers and is typically used by software developers, transmitters and enterprise compliance teams [citation:10].
A2A vs. the IRIS Taxpayer Portal
| Aspect | IRIS Taxpayer Portal | IRIS A2A |
|---|---|---|
| File format | CSV template | XML |
| Record limit | 250 per CSV file | Up to 100 MB per transmission |
| Submission method | Manual upload and review | System-to-system API |
| Best for | Lower volumes, ad-hoc filing | High volumes, recurring automated workflows |
IRIS A2A does not use the fixed 250-record limit that applies to the Taxpayer Portal [citation:3]. A2A supports transmissions of up to 100 MB at a time, and each submission must contain the same form type and tax year [citation:11].
What you need for A2A filing
- IRIS TCC — Transmitter Control Code issued by the IRS.
- API Client ID — Required for A2A filers.
- Schema package — Available after applying for an IRIS TCC.
A2A consent requirements and access token generation are specified in IRS Publication 5718, the IRIS Electronic Filing Application to Application Specifications [citation:9].
The IRIS XML structure
IRIS uses XML to define the structure and content of information returns. The payload is organized into three levels [citation:9]:
- Transmission — The top-level container with transmitter metadata. Can contain one or more submissions.
- Submission — Groups data for a specific form type and tax year. Includes a submission header with a count of the returns.
- Record — The individual information return, such as a single Form 1099-NEC for one recipient.
Each level requires unique identifiers: the Unique Transmission Identifier (UTID), Submission Identifier (SID), and Record Identifier (RID).
How Novus helps
- Build and maintain the A2A integration layer for your existing ERP, accounting or marketplace platform.
- Generate XML that conforms to the IRIS schema package across the transmission, submission and record levels.
- Apply enveloping XML digital signatures and AES-256-CBC encryption.
- Handle OAuth 2.0 authentication and API client ID management for the IRIS A2A endpoints.
- Validate data before transmission to prevent rejection of the entire batch.
- Process acknowledgements and status responses automatically.
Related resources
Frequently asked questions
What is the A2A transmission size limit?
A2A supports up to 100 MB at a time. Each submission must contain the same form type and tax year [citation:11].
Do I need an API client ID for A2A?
Yes. An API client ID is required for A2A filers in addition to an IRIS TCC [citation:10].
Can A2A handle multiple form types in one transmission?
Each submission must contain the same form type. You can include multiple submissions within a single transmission if they share the same form type and tax year, but 1099-NEC and 1099-MISC must be submitted separately [citation:11].
What publication covers the A2A specifications?
IRS Publication 5718, Information Returns Intake System (IRIS) Electronic Filing Application to Application (A2A) Specifications [citation:9].