The IRS is shutting down the FIRE system on December 31, 2026. Organizations that rely on it for high-volume 1099 filing will need to transition to IRIS for tax year 2026 filings due in January 2027.
IRIS introduces changes that affect both data structure and submission workflows, including XML-based formats, real-time validation, new TCC credentials, and required testing before production access.
For teams currently using FIRE, this transition requires coordinated updates across data, systems, and filing processes within a fixed timeline.
This guide is written for compliance teams and IT departments at organizations filing 100 or more information returns annually. It outlines what is changing, the steps required to prepare, and how to evaluate filing readiness.
Why the IRS Is Retiring FIRE and What IRIS Was Built to Do
FIRE (Filing Information Returns Electronically) has been the IRS’s bulk eFiling infrastructure since the 1980s, built on a fixed-width flat-file format (Publication 1220). While stable, it does not support modern validation or structured data workflows.
IRIS (Information Returns Intake System), launched in 2022, replaces FIRE with XML-based schemas (Publication 5718), real-time TIN validation, and dual intake paths: a portal for smaller filers and A2A API for enterprise filers.
The key shift: under FIRE, errors surfaced later as CP2100 notices. Under IRIS, errors are rejected at submission. That moves validation from post-filing correction into pre-submission preparation.
IRS FIRE vs IRIS: Five Critical Differences Enterprise Filers Must Understand
| Dimension | IRS FIRE (Legacy) | IRS IRIS (New System) |
| File Format | Fixed-width flat file (Pub 1220) | XML schema (Pub 5718 for A2A) |
| TCC Credential | FIRE-specific TCC (Transmitter Control Code) | New IRIS-specific TCC (non-transferable) |
| Name Fields | Combined | Separate fields required |
| TIN Validation | Post-filing | Real-time rejection |
| Submission Method | File upload | Portal (<200) / A2A (200+) |
| Testing Requirement | Not mandatory | ATS (Assurance Testing System) is required before production access |
Each difference translates into workflow impact. Real-time validation, for example, requires resolving errors before submission instead of after.
Enterprise Filing Path: IRIS Portal vs A2A
IRIS offers two filing paths
IRIS Taxpayer Portal: For fewer than 100 information returns. Supports manual entry or CSV upload. No API integration required. Not viable for enterprise-scale filers.
IRIS Application-to-Application (A2A): Required for 100+ returns. System-to-system XML submission via IRS API. Requires an IRIS TCC and successful ATS test transmission before production access is granted.
If your current FIRE workflow uses automated batch transmission rather than manual upload, you are on the A2A path. This is an integration and workflow change, not a tool switch.
Third-party platforms like 1099Pro remove the need to build A2A internally by handling XML generation, transmission, and validation workflows.
Why FIRE-Based Workflows Break Under IRIS
Most FIRE-based workflows break immediately under IRIS because they were designed for flat files and delayed validation.
- Flat-file outputs are no longer accepted → XML generation is required
- Combined name fields fail validation → requires upstream data restructuring
- Real-time rejection replaces delayed feedback → increases correction pressure
- Manual correction workflows do not scale → validation must happen before submission
Data readiness is where most migration timelines slip, not at submission.
How Enterprise Filers Should Execute the FIRE-to-IRIS Migration
This is the step sequence that matters for compliance and IT teams. Each step depends on the one before it.
Step 1: Apply for an IRIS TCC now
Your existing FIRE TCC cannot be used with IRIS. A new IRIS-specific Transmitter Control Code must be obtained through the IRS e-Services system. The application requires at least two Responsible Officials with verified ID.me accounts for most business entities. Processing takes up to 45 business days. Do not wait.
Step 2: Audit and clean your payee master data
Split name fields, validate TIN formats, and remove legacy formatting issues. For high-volume filers, this becomes a structured data remediation effort. Incomplete data will fail ATS (Assurance Testing System) or production validation.
Step 3: Decide on your filing method
Build the A2A integration internally, or use a certified third-party platform. Building internally means owning XML generation, schema compliance, ATS testing, and ongoing schema updates as the IRS revises them. Most enterprise compliance teams opt for providers to reduce long-term overhead.
Step 4: Complete ATS testing
ATS is required for all A2A filers before production access is granted. The IRS typically opens ATS in the fall, in November, based on recent cycles. Your TCC starts in “Test” status and only moves to “Production” after successful ATS transmissions are accepted. Use test TINs only (must begin with three zeros in the test environment). Do not submit real taxpayer data during ATS.
Step 5: Run parallel filing during the 2026 season
Tax year 2025 returns (filed early 2026) can still go through FIRE. Use this window to run your IRIS workflow in parallel and validate the end-to-end process before FIRE is no longer available as a backup.
Step 6: Update upstream systems
ERP, AP, and HR system outputs must align with IRIS-compliant XML structure before the January 2027 hard deadline. This is often the longest lead-time item on the migration project plan.
XML Schema and Data Format Requirements for A2A Filers
The move from FIRE’s flat-file format to IRIS XML is the most significant technical change for enterprise A2A filers.
IRIS uses hierarchical XML schemas (Publication 5718), where each transmission contains submissions and individual records. This replaces FIRE’s flat-file structure, where fields are tied to fixed positions.
The main operational impacts are:
- XML replaces flat-file outputs
- Name fields must be separated (first, middle, last, suffix)
- Validation occurs at submission, not after processing
The name field requirement is often the biggest issue. Combined name fields will fail validation, requiring payee data to be restructured before filing.
IRIS also introduces real-time rejection. If required fields are missing or TIN and name data do not match IRS records, the submission is rejected immediately.
For high-volume filers, this requires defined workflows for identifying, correcting, and resubmitting errors under a deadline.
Schema packages are accessed through the IRS Secure Object Repository (SOR) with an approved IRIS TCC.
Should You Build A2A Internally or Use a Filing Provider?
Enterprise filers who currently use a third-party 1099 platform need to evaluate whether that provider is IRIS-ready for A2A transmission, not just portal-ready. The distinction matters.
Building A2A internally means owning API integration, XML generation, schema compliance, ATS testing, and ongoing maintenance as IRS requirements evolve. This is a software engineering effort tied directly to a compliance deadline.
Using a certified filing platform like 1099Pro shifts the A2A infrastructure responsibility to the provider. Your team exports data in a defined format, while the provider manages XML generation, A2A transmission, acknowledgments, and rejection handling. Schema updates are handled externally, reducing internal lift.
For most enterprise teams, the decision is operational. Maintaining A2A infrastructure long term is resource-intensive, and the transition itself already requires significant coordination across systems, data, and compliance workflows.
Timeline and Risk Map for Enterprise Migration
| Milestone | Window | Risk |
| TCC application + data audit | Now–Q2 2026 | Blocks all downstream steps |
| Vendor selection/integration | Q2–Q3 2026 | Limited testing window |
| ATS testing | Q3 2026 | No production access |
| Parallel filing | Late 2026 | No live validation before cutoff |
| FIRE shutdown | Jan 2027 | No eFile channel |
| 1099 deadline | Feb 2027 | Immediate penalties |
Each milestone depends on the previous one. A delayed TCC application compresses every step that follows. Organizations that begin this process in Q4 2026 will almost certainly fail the ATS requirement before the deadline.
What Happens If You Miss the IRIS Transition Deadline
After December 31, 2026, FIRE will not accept submissions. There is no grace period and no phased rollout.
Organizations without a compliant IRIS filing path face two outcomes: paper filing (which requires an IRS waiver and is operationally infeasible at enterprise volumes) or missing their filing deadlines. IRS penalties for late or missing information return filings can reach up to $310 per form, with higher exposure for intentional disregard. For an organization filing 10,000 returns, that exposure compounds quickly.
There is also a correction workflow consideration that many teams overlook. Tax year 2025 returns filed through FIRE must still be corrected through FIRE, even after it retires for new submissions. This requires maintaining FIRE access into early 2027 for corrections while operating IRIS for current filings.
Preparing for IRIS: What Enterprise Filers Need to Do Now
The FIRE-to-IRIS transition is mandatory, with a fixed deadline. For enterprise filers, January 2027 requires a new IRIS TCC, A2A XML integration, ATS test clearance, and payee data remediation, all before filing season begins.
The primary risk is timing. The TCC application can take up to 45 business days, and ATS testing cannot begin until it is approved. Data remediation and upstream system updates across ERP, AP, and HR systems often take longer than expected, especially at scale.
For teams managing high filing volumes, delays in any one step can compress the entire timeline and limit the ability to test before the deadline.
1099Pro supports enterprise filers through the transition by handling A2A transmission, schema management, and correction workflows.
Get started with a 7-day free trial today.
Frequently Asked Questions
Can I use my existing FIRE TCC for IRIS?
No. FIRE TCCs and IRIS TCCs are system-specific and not interchangeable. You must apply for a new IRIS TCC through IRS e-Services. Processing can take up to 45 business days, so this should be completed early in your migration timeline.
What is the threshold for IRIS A2A versus the portal?
The IRIS Taxpayer Portal supports fewer than 100 information returns. Organizations filing 100 or more must use the A2A API. If your current workflow relies on automated batch transmission through FIRE, you will need to transition to A2A.
Is ATS testing required for all IRIS filers?
No. ATS testing is required only for A2A filers. Organizations using the IRIS Taxpayer Portal (fewer than 100 returns) do not need to complete ATS. For A2A filers, ATS completion is a prerequisite for production access. Your TCC will not move from “Test” to “Production” status without it.
Does IRIS support Form 1042-S?
Yes. As of January 2026, IRIS accepts Form 1042-S for tax year 2025 filings. Organizations that previously filed 1042-S through FIRE can transition both 1099 series and 1042-S filing into a single IRIS workflow.
What happens to corrections for returns originally filed through FIRE?
Corrections for FIRE-filed returns must still be submitted through FIRE, even after it is retired for new submissions. Organizations should maintain FIRE access into early 2027 to handle corrections for tax year 2025.