How to Migrate From FIRE to IRIS (Step by Step)

Why Your FIRE Files Won’t Just Upload to IRIS

The instinct is a reasonable one: you have a folder of FIRE-format files that the IRS accepted last year, so surely you can point them at the new system and be done. You cannot. IRIS is a different platform with a different identity model and a different file format, and there is no IRS tool that lifts a FIRE submission into IRIS unchanged.

Two separate things have to change before a single record reaches IRIS. The first is your identity on the system. Your FIRE TCC does not carry over, because the IRS treats FIRE and IRIS as separate systems with separate Transmitter Control Codes and no conversion path between them, so you begin with a fresh IRIS application rather than a migrated account. The second is the file itself, which has to be reshaped. FIRE expects a fixed-width flat file built to the legacy Publication 1220 record layout, where every value is identified by its character position on the line, while IRIS accepts data through its own channels and named formats. The bytes you already have simply do not line up with what IRIS reads.

The Deadline Behind the Migration

Migration feels like a someday project until you do the arithmetic. The IRS plans to retire the FIRE system after the tax year 2026 filing season, with FIRE accepting its last submissions and shutting down following December 31, 2026. That date is the outer wall, and it is the one most people fixate on. The constraint that actually governs your calendar, though, sits well in front of it.

To file on IRIS you must already hold an approved IRIS TCC, and the suitability review behind that approval takes a minimum of 45 business days — roughly nine working weeks — and cannot be expedited. Once you stack identity verification, the application itself, and any follow-up the IRS asks for on top of that review, a realistic runway stretches to somewhere between two and four months. The date that governs you is not the FIRE sunset; it is the day you must start your IRIS application in order to be approved before your first filing deadline.

The Migration Path: Four Stages, In Order

A clean migration breaks into four stages, and the order matters as much as the steps themselves. Most of the pain in a botched migration comes from skipping ahead: people convert their files before they hold a TCC, or they try to file before they have tested, and then the work has to be redone from the beginning. The table below lays out the sequence and who each stage applies to.

Step 1: Apply for a New IRIS TCC

This is the long-lead item, so it is the one you start first. The application is the Information Returns (IR) Application for TCC in IRS e-Services, and it is the same form regardless of which 1099-series forms you intend to file. The full depth of this step lives in our companion walkthrough on getting your IRIS TCC; what follows here is the shape of it, so you can schedule the migration realistically.

Step 2: Choose Portal or A2A

IRIS gives you two ways in, and the one you choose decides how much conversion work stands between you and your first filing. The right call comes down to your volume and whether you have developers on hand, not to which system you happened to use before.

The Taxpayer Portal (TP) is the web route: you enter records by hand or upload a CSV built to the IRIS template. It needs no developers and no schema work, which makes it the natural landing spot for most filers leaving FIRE. A2A (Application-to-Application) is the machine-to-machine route, where your software sends IRIS XML directly over an API. A2A scales to very high volume, but it adds a schema build and mandatory assurance testing before you can go live. Many former FIRE bulk transmitters end up on A2A, while smaller filers are usually better served by the Portal’s CSV upload template.

Step 3: Convert Your FIRE Files

This is the stage people consistently underestimate. Your FIRE files are fixed-width records built to the legacy Publication 1220 layout, where every field is identified by its character position on the line. IRIS does not read by position at all. The Portal reads a CSV mapped to its own column template, and A2A reads named XML elements, so either way the same underlying data has to be lifted out of the flat file and re-expressed in the target shape.

The most visible difference is the recipient name. FIRE packs the entire payee name into a single position-based field, whereas IRIS expects discrete, named elements for the separate parts of a name. One flat-file field becomes several distinct XML elements, and the conversion has to split it correctly — this is exactly where most mapping errors hide:

These positions and element names are illustrative, shown for orientation only; the real record layout is defined by IRS Publication 5718 for A2A and by the IRIS Portal CSV templates for the web route. For the full field-by-field mapping, see our guide to converting FIRE flat files to IRIS XML.

Step 4: Test, Then File Your First Batch

With a TCC in hand and your data converted, you are ready to transmit — but A2A filers have one gate left to clear. Before any live transmissions, you build XML against the IRIS schema and pass Assurance Testing System (ATS) scenarios, which is how the IRS confirms your output is well-formed before it ever touches production. Portal filers skip ATS entirely; you simply log in and upload your CSV or key the records in by hand.

For your first real batch, file small. Submit a single form type for a handful of payees, confirm that you receive an acknowledgment back, and verify the status before you send the rest. IRIS returns a receipt for accepted transmissions and rejection detail for failures, so a small first run surfaces any mapping problem cheaply — on ten records rather than ten thousand. Once that small batch clears, you can scale up with confidence.

Common Rejection Reasons (and How to Avoid Them)

Migration introduces failure points the old FIRE-to-FIRE routine never had: a new credential, a new file shape, and a new test gate. These are the ones that bite migrating filers most often, and every one of them is avoidable if you see it coming.

Skip the File Conversion Entirely: The e1099f Advantage

Everything above is the work of migrating yourself — the new TCC, the format conversion, and the testing. There is a second path that sidesteps most of it: file through an IRS-authorized provider that already holds an IRIS TCC and accepts the files you already produce.

If you’d rather not re-platform under deadline pressure, this is the fastest compliant route from FIRE to IRIS — CF/SF included.

Frequently Asked Questions

Not tax advice. This guide is general information about IRS procedures and may change as the IRS updates IRIS and finalizes the FIRE retirement timeline. Confirm current requirements in the official IRS publications linked above, and consult a tax professional for your situation.