The FIRE-to-IRIS migration is straightforward in principle. In practice, we’re already seeing businesses make the same mistakes – mistakes that won’t surface until January, when deadlines are real and FIRE is gone.
Here are the five most common pitfalls, why they happen, and how to avoid them while there’s still time.
Mistake #1: Underestimating the TCC Timeline
This is the mistake that catches the most organizations. The IRS says IRIS TCC applications take up to 45 days to process. That’s not a worst-case estimate – it’s the standard timeline.
Here’s how the math works against you:
- Apply November 15 → Approval by December 30 (best case)
- Apply December 1 → Approval by January 15 – past the FIRE shutdown, possibly past the 1099-NEC deadline
- Apply after December 15 → You’re filing late. Period.
And that’s assuming you only need one TCC. Some organizations need separate TCCs for production and testing. Each application runs through the same 45-day process.
Mistake #2: Assuming FIRE Files Work With IRIS
We hear this more often than you’d expect: “We’ll just upload our FIRE file to IRIS instead.” It won’t work.
FIRE uses fixed-width flat text files (Publication 1220 format). IRIS uses structured XML. They’re fundamentally different data formats. Uploading a FIRE flat file to IRIS is like trying to open a Word document in a spreadsheet – the system doesn’t know what to do with it.
This assumption is especially dangerous for organizations with automated pipelines. If your ERP, payroll system, or custom scripts generate FIRE-format files, that output needs to change – either to IRIS XML or to a format that a provider can convert.
Mistake #3: Skipping the Sandbox
If you’re building a direct IRIS integration, the IRIS testing sandbox exists for a reason. But under time pressure, testing is usually the first thing that gets cut.
Here’s what happens when you skip the sandbox:
- Schema validation failures that could have been caught in test hit you in production with real returns and real deadlines
- Authentication issues – OAuth token handling, credential rotation, session management – surface at the worst possible time
- Edge cases in your data (special characters in names, unusual TIN formats, foreign addresses) cause rejections you’ve never seen before
- Error handling gaps mean your system doesn’t know what to do when IRIS returns an unexpected response
The sandbox mirrors production validation. Every error you find there is an error you don’t discover in January. For a complete reference on what to expect, see our IRIS error codes guide.
Mistake #4: Forgetting About Corrections
Most organizations focus their migration planning on original submissions. But what about corrections? If you’ve filed 1099s through FIRE before, you know that corrections are a regular part of the workflow – TIN mismatches, wrong amounts, name changes.
With FIRE, corrections used the same flat-file format with a “corrected” indicator. With IRIS, corrections go through a different process. The XML schema for corrections differs from original submissions. The API endpoints may differ. Your workflow needs to handle both.
Organizations that plan only for original filings discover this gap in February or March, when the correction requests start coming in from payees and recipients.
Mistake #5: Not Having a Fallback Plan
Technology projects go wrong. Timelines slip. Integrations break. The organizations most at risk aren’t the ones with aggressive migration plans – they’re the ones with only one plan.
If your IRIS migration depends on:
- A single developer finishing the XML integration on time
- A TCC application being processed without delays
- A vendor completing onboarding by a specific date
- No surprises in the IRS schema or API
…then you need a Plan B. Because when FIRE shuts down on December 31, there is no extension, no grace period, and no “we’ll get it done next week.” If your primary plan isn’t working by mid-December, you need an alternative that can be activated immediately.
The Common Thread
All five mistakes share a root cause: underestimating lead time. The FIRE-to-IRIS transition isn’t technically difficult for most organizations – but it has long lead times that punish late starts. TCC applications, development cycles, testing periods, and vendor onboarding all take weeks, not days.
The transition timeline is fixed. December 31 doesn’t move. The question is whether you spend the next six months working through this methodically or spend January in crisis mode.
Frequently Asked Questions
What if we’ve already applied for a TCC but haven’t started building?
You’re ahead of most organizations. While waiting for TCC approval, start documenting your data requirements and evaluating whether to build or use a provider. If your TCC arrives and you realize a direct integration won’t be ready in time, a provider is your safety net.
Our vendor says they’re “IRIS ready” but can’t show us a test filing. Should we worry?
Yes. “IRIS ready” should mean they’re actively submitting through IRIS – not planning to. Ask for specifics: When was their last IRIS submission? What form types have they submitted? Can they show you a successful filing acknowledgment? If the answers are vague, start evaluating alternatives.
We file through a payroll provider. Do we need to do anything?
Contact your payroll provider and ask three questions: (1) Are you filing through IRIS? (2) Will our 1099s be filed through IRIS by default starting January 2027? (3) Do we need to do anything on our end? If they confirm all three, you’re covered. If not, you need a backup plan.
Is it too late to start in October?
For a direct IRIS integration, October is late but not impossible – if you move fast and nothing goes wrong. For signing up with a filing provider, October is fine. The key is to not wait until October to decide. Make the build-vs-buy decision now and act in October accordingly.
Do penalties apply if we file on time but IRIS rejects some returns?
Generally, if you make a good-faith attempt to file on time and correct rejections promptly, penalties may not apply. But “good faith” gets harder to argue when the rejection was caused by untested XML or an integration you built at the last minute. The safer path is to avoid rejections by testing thoroughly.
Start Today, Not Tomorrow
Every week you wait narrows your options. The FIRE end-of-life checklist gives you a complete rundown of what needs to happen before December. The migration guide walks through the process step by step.
Or skip the project entirely. BoomTax accepts your data – even FIRE-format flat files – and handles the IRIS submission for you. No TCC. No XML. No sandbox. No mistakes.
Create your free BoomTax account and test an upload today. It takes 15 minutes, and you’ll know your January filing is covered.
BoomTax, The Boom Post, and its affiliates do not provide tax, legal or accounting advice. This material has been prepared for informational purposes only, and is not intended to provide, and should not be relied on for, tax, legal or accounting advice. You should consult your own tax, legal and accounting advisors prior to engaging in any transaction.
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