If your business files 1099s, W-2Gs, or other information returns with the IRS, a major change is underway. The FIRE to IRIS transition marks the end of a legacy filing platform that has been in use since the 1980s — and businesses of all sizes need to understand what’s changing, why it matters, and how to prepare.
This guide breaks down everything you need to know.
What Is the IRS FIRE System?
The Filing Information Returns Electronically (FIRE) system is the IRS platform that has processed electronic information return submissions since the 1980s. It supports Forms 1099, 1042-S, 3921, 3922, and other information returns.
FIRE was built on older mainframe technology and uses the 1220 flat file format, an ASCII-based, compressed file structure that filers upload directly to the IRS portal. While functional for decades, the system has significant limitations:
- No real-time validation: errors are identified only after the IRS processes your submission.
- Full file replacement required for corrections: you cannot target a single erroneous record.
- Limited testing environment: filers have restricted opportunities to test submissions before deadlines.
- File size cap: FIRE accepts files up to 100MB compressed.
The FIRE system will be permanently decommissioned on December 31, 2026.
What Is the IRIS Filing System?
IRIS, the Information Returns Intake System is the IRS’s modern replacement for FIRE. It is a web-based platform built on current technology, designed to modernize how businesses submit information returns electronically.
IRIS officially launched in November 2025.
Key capabilities of the IRIS system for businesses include:
- Real-time validation — errors are flagged before your submission is accepted, reducing rejections.
- Targeted corrections — fix individual records without resubmitting an entire file.
- Downloadable recipient copies — access filed forms directly within the platform.
- Extension requests — submit extension requests from within IRIS.
- Year-round testing environment — test submissions at any point, not just around filing deadlines.
- XML-based file format — structured data transmission replacing the legacy 1220 ASCII flat file.
- Larger file size allowance — up to 250MB uncompressed, compared to FIRE’s 100MB compressed limit.
IRIS currently accepts all Forms 1099 series, plus Forms 1042-S, 1097-BTC, 1098 series, 3921, 3922, 5498 series, W-2G, and more for Tax Year 2025.
FIRE vs. IRIS: Key Differences at a Glance
| Feature | FIRE (Legacy) | IRIS (New) |
| Status | Retires December 31, 2026 | Mandatory from Tax Year 2026 |
| File Format | 1220 ASCII flat file | XML |
| File Size Limit | 100MB compressed | 250MB uncompressed |
| Validation | Post-filing | Real-time, pre-acceptance |
| Corrections | Full file replacement | Targeted record correction |
| Transmission Method | Direct portal file upload | Taxpayer Portal (under 100 returns) or A2A API (100+ returns) |
| TCC Requirement | FIRE-specific TCC | New IRIS-specific TCC required |
| Testing Environment | Limited | Year-round availability |
| Authentication | Username/password login | ID.me account required |
Why the IRS Is Transitioning Systems
The FIRE to IRIS transition is part of the IRS’s broader modernization initiative, aimed at reducing paper filings, improving data accuracy, and bringing federal tax infrastructure up to current technology standards.
The IRS’s stated goals for IRIS include:
- Improving efficiency and accuracy in information return processing.
- Supporting the agency’s paperless processing initiative — paper information return filings will eventually be eliminated entirely.
- Enabling real-time data validation to reduce errors and downstream compliance issues.
- Providing a more user-friendly, secure platform that meets modern cybersecurity standards.
The shift also reflects the scale of electronic filing IRS IRIS must handle. As the e-file mandate threshold has dropped to 10 or more aggregate returns, the volume of electronic submissions has grown substantially — requiring infrastructure that FIRE’s 1980s architecture was not designed to support.
How the Change Impacts Businesses
The impact of FIRE to IRIS varies depending on your filing volume and current systems. Here is what businesses need to know.
Filing Volume Determines Your Path
IRIS offers two filing methods, and the threshold between them is a critical detail:
Option 1 — IRIS Taxpayer Portal (fewer than 200 returns):
- Web-based filing with manual data entry or CSV upload.
- No special software required.
- Requires an IRIS Transmitter Control Code (TCC) and an ID.me account.
- Confirmation received within approximately 48 hours.
Option 2 — Application to Application (A2A) (200 or more returns):
- Automated XML submissions via direct API connection.
- Requires an IRIS A2A-specific TCC (separate from the portal TCC).
- Requires an API Client ID, completion of the IRIS Assurance Testing System (ATS), and download of the current schema package.
- Direct file upload to an IRS portal is no longer an option at this volume.
For organizations that currently generate 1220 text files and upload them manually, the A2A requirement represents a significant workflow change.
New Data Field Requirements
IRIS requires separate fields for first and last names, unlike the combined name field in the 1220 FIRE format. This seemingly minor change can create Name/TIN mismatches if not handled correctly — and mismatches can result in IRS penalties.
Businesses must audit their source data and ensure their filing workflows can correctly split and map name fields before transitioning.
Real-Time Validation Changes the Error-Handling Process
Under FIRE, you submitted a file and found out later whether it was accepted. Under IRIS, validation happens before acceptance. This is a significant operational improvement — but it also means your data preparation process needs to be clean and accurate upstream, rather than relying on post-submission error review.
State Filing Remains Complex
As of early 2026, most U.S. states still use the FIRE format to process information returns. Only a small number have adopted the IRIS schema. This means many businesses will need to maintain dual filing capabilities — submitting in IRIS XML for federal returns and in FIRE format for state-level reporting.
IRIS-compatible 1099 software that can manage both federal and state filing requirements will be critical during this transitional period.
Key FIRE to IRIS Timeline
| Milestone | Date |
| IRIS launches | November 2025 |
| IRIS Production for Filing Season 2026 opens | January 6, 2026 (9:00 a.m. ET) |
| Last tax year eligible for FIRE filing | Tax Year 2025 |
| FIRE system decommissioned | December 31, 2026 |
| First tax year requiring mandatory IRIS filing | Tax Year 2026 (returns filed in early 2027) |
Preparing for the FIRE to IRIS Transition
There is one filing season remaining before FIRE retires. Here is a step-by-step preparation framework for businesses.
Step 1 — Determine Your Filing Volume
Identify whether you will use the IRIS Taxpayer Portal (under 200 returns) or A2A (200 or more returns). This determines the scope of your technical preparation and the type of TCC you will need.
Step 2 — Register with the IRS and Obtain an IRIS TCC
Your existing FIRE TCCcannot be used for IRIS — a new TCC is required. The TCC application process can take up to 45 days to complete. Apply early.
All users, including Responsible Parties and Authorized Delegates, must authenticate via their own individual ID.me accounts.
Each business taxpayer must designate at least two Responsible Parties and may assign up to two Authorized Delegates.
Step 3 — Obtain an API Client ID (A2A filers only)
If you are filing 100 or more returns, apply for an IRIS A2A-specific TCC and an API Client ID. Download the current IRIS schema package and complete the IRIS Assurance Testing System (ATS) process before your first live submission.
Step 4 — Audit Your Source Data
Review your payer and payee data for IRIS compatibility:
- Ensure first and last name fields are separated correctly.
- Validate TINs against IRS records to reduce Name/TIN mismatches.
- Confirm your data can be mapped to the XML schema required by IRIS.
Step 5 — Assess Your Systems for XML Readiness
If you use a homegrown system or core platform to generate your filings, assess whether it can output IRIS-compliant XML. For bulk filers using A2A, this includes testing the API connection and completing the ITS Assurance Testing System (ATS) requirements.
Step 6 — Choose IRIS-Compatible 1099 Software
For most businesses, the most practical path is to use 1099 software IRIS compatible that manages the XML formatting, API connection, TCC management, and validation requirements on your behalf — freeing your team from the technical complexity of the transition.
A cloud 1099 reporting solution that is already certified for IRIS can eliminate the need to build or re-engineer internal infrastructure.
Frequently Asked Questions
What is the IRS IRIS system?
IRIS — the Information Returns Intake System — is the IRS’s new electronic filing platform for information returns. It replaces the legacy FIRE system and uses XML-based file formatting, real-time validation, and modern API-based transmission. IRIS officially launched in November 2025. IRS IRIS Overview
Is the FIRE system being retired?
Yes. The IRS has confirmed the FIRE system will be permanently decommissioned on December 31, 2026. Tax Year 2025 is the last filing year for which FIRE can be used. All Tax Year 2026 returns — filed in early 2027 — must be submitted through IRIS. IRS FIRE System Documentation
Who needs to use IRIS?
Any business or individual required to file information returns electronically must transition to IRIS. If you file 10 or more aggregate information returns per year — including Forms 1099-NEC, 1099-MISC, 1099-INT, 1099-DIV, 1099-K, 1042-S, 1098 series, 3921, 3922, 5498 series, and W-2G — you are required to e-file and will need to use IRIS starting with Tax Year 2026. IRS General Instructions for Certain Information Returns
How can businesses prepare for the FIRE to IRIS transition?
Start by determining your filing volume, applying for an IRIS-specific TCC (allow up to 45 days), and auditing your data for XML compatibility. If you file 100 or more returns, begin A2A testing early. The most efficient path for most businesses is to use IRIS-compatible 1099 filing software that handles the technical requirements on your behalf. For guidance on 1099 filing deadlines and correcting 1099 forms under the new system, your compliance software should address both.
The IRS IRIS transition is not optional — and with just one filing season remaining before the FIRE system retires, now is the time to assess your readiness and take action.
Get ahead of the change and cut your preparation time in half with 1099Pro Cloud. With a 1099Pro Cloud subscription you don’t need access to the IRIS system or a new TCC to file your 1099, 1042, or W-2 forms. Get started with a 7-day free trial today.