IRISfile
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Free tool

FIRE file validator

Check a Publication 1220 fixed-width file for errors before you file it. Row by row, with the reason. No signup, no upload, no limit on how many times you run it.

Drop your FIRE file here

Or choose one. It is checked in this browser tab and never uploaded.

Questions

Is my file uploaded anywhere?
No. The check runs in this browser tab. A FIRE file lists payees with their Social Security numbers in plaintext, so the file never leaves your machine and we never see it. You can confirm this: open your browser network tab and drop a file in. Nothing is sent.
What does it check?
Record structure first: the T, A, B, and C record sequence, record lengths, and payment amount fields. Then each payee record against IRS rules: TIN format by type, ZIP codes, state and country codes, payer name, and whether the payment amount codes are ones the form actually allows.
Which forms does it read?
1099-NEC, MISC, INT, DIV, R, B, and S. It also flags records that cannot be filed through IRIS yet, such as 1099-B and 1099-S, so you learn that before the deadline rather than after a rejection.
Does a clean result mean the IRS will accept it?
It means the file is structurally sound and passes the Publication 1220 rules this tool implements. It is not an IRS pre-submission check. The IRS validates against the IRIS XML schema at transmission, and a schema-invalid transmission cannot be replaced, it has to be refiled as a new original.
FIRE is retiring. Why validate a FIRE file at all?
Because FIRE accepts tax year 2025 filings until it shuts down on December 31, 2026, and because the file you already produce is the input to IRIS conversion. A file that is clean in Pub 1220 terms converts cleanly to IRIS XML.

FIRE retires on December 31, 2026 and IRIS is mandatory from January 2027. If you are working out what that means for your filings, read what replaces the IRS FIRE system.