IRIS Taxpayer Portal, A2A, or a Provider? Choosing How to E-File 1099 Forms in 2027

Tax year 2026 is the first filing season when IRIS is the only way to e-file information returns with the IRS. The IRS’s FIRE system page confirms that FIRE stops accepting submissions on November 19, 2026, and that after January 1, 2027, IRIS handles everything: current-year returns, prior-year returns, and corrections.

For organizations that have filed through FIRE for years, that raises a practical question: do you build IRIS filing into your own systems, or hand it to a provider?

There’s no single right answer. It depends on your volume, your IT resources, and how much of the filing process you want to own. This guide walks through what each option actually involves, so you can make the call with clear eyes.

For background on what’s changing between the two systems, see our FIRE to IRIS transition guide.

Your three options

1. File yourself through the IRIS Taxpayer Portal. The IRS’s free web portal lets you key in forms or upload a CSV file. It’s designed for lower volumes: each submission is capped at 100 forms.

2. Build your own A2A integration. IRIS’s application-to-application (A2A) channel is the bulk-filing route. Your systems generate XML and transmit it directly to the IRS. The IRS notes that A2A requires special software or a third-party provider.

3. File through a provider. A provider like TAB1099 files under its own IRIS credentials. You send your data; the provider handles conversion, validation and transmission.

Options 1 and 2 are the “in-house” paths. Here’s what each one takes.

What building in-house really involves

The Taxpayer Portal

The portal is free and doesn’t require any development work. But you still need to:

• Apply for an IRIS Transmitter Control Code (TCC). Your FIRE TCC does not carry over; the IRS requires current FIRE users to complete a new IRIS application for TCC.
• Have the authorized users in your organization sign in to IRS e-Services with identity verification.
• Format your data to match the IRS’s CSV templates and current form layouts. For example, forms revised for 2026 split the address into separate fields.
• Manage uploads in batches of 100 forms or fewer, and file corrections manually through the portal.

For an organization filing a few dozen forms, that’s manageable. For one filing thousands, the batch limit and manual workflow add up quickly.

A direct A2A integration

This is where “in-house” becomes a genuine software project. According to the IRS’s IRIS e-file page, a direct A2A setup requires:

• An IRIS A2A TCC and a separate API Client ID to connect to the IRS system.
• The IRS schema package, which you receive only after applying for your IRIS TCC.
• An XML generator. FIRE used a flat, fixed-position file. IRIS A2A uses XML that must validate against the IRS schemas and business rules. Your existing FIRE export won’t work as-is.
• A secure web service integration with the IRS, including authentication, acknowledgments, status checks and error handling, built to the specifications in Publication 5718.
• Passing the IRS Assurance Testing System (ATS) before you’re allowed to transmit live returns, including a one-time communication test.
• Ongoing maintenance. The IRS publishes schemas and business rules for each tax year, and form changes have to be built in each time. For tax year 2026 alone, Forms 1099-NEC and 1099-MISC were updated to report cash tips and overtime compensation, and several forms gained separate address fields.

Timing is the part organizations underestimate. According to Publication 1099, a typical TCC application is processed within 45 business days, though processing times vary. And IRIS A2A testing generally doesn’t open until November. An organization starting from scratch in the fall is compressing application, development, testing and go-live into the weeks right before year-end close, and right before the 2027 filing deadlines.

The case for building in-house

Building your own integration can make sense if:

• You file very high volumes and have in-house developers with capacity to spare.
• Filing is core to your business. For example, you’re a software company whose product generates information returns.
• You need deep, custom integration with internal systems and are prepared to maintain it year after year.
• You already have IRIS experience from filing tax year 2025 returns through IRIS.

For low-volume filers with clean data, the Taxpayer Portal can also be a reasonable in-house choice.

The case for outsourcing

For most organizations, 1099 filing is a compliance obligation, not a core competency. Outsourcing makes sense when:

• You don’t want to apply for or manage a TCC. Filing through a provider means working under the provider’s credentials.
• You’d rather not change your systems. A good provider accepts the files you already produce.
• Your IT team has other priorities, especially at year-end.
• You want someone else to absorb annual IRS changes: schema updates, new form boxes, new business rules. (See our rundown of what changed on 1099 forms for 2026 for a sense of how much moves each year.)
• You want printing, mailing and recipient delivery handled too, not just the IRS filing.

The trade-off is a service cost and less direct control over the transmission itself. The right provider narrows that gap by letting you review data before anything reaches the IRS.

A quick way to decide

	IRIS Taxpayer Portal	In-house A2A	Provider (e.g., TAB1099)
Your own IRIS TCC	Required	Required, plus API Client ID	Not required
Development work	None	Significant	None
IRS testing (ATS)	Not required	Required	Handled by provider
Works with your FIRE file	No	No, needs XML conversion	Yes
Best for	Low volumes	High-volume filers with dev resources	Most organizations that want to stay focused on their core work

How TAB1099 fits

If outsourcing looks like the right path, TAB1099 offers two ways to work with us, covering the full range of 1099, 1098 and W-2G forms:

• Self-Service E-Filing. Upload your FIRE, CSV or Excel file by direct upload, API or SFTP. We convert it to IRIS XML, validate every record against IRS business rules, and file under our own TCC. You review the converted data before it’s transmitted.
• Full 1099 Service. Upload your data once and we handle everything: IRIS filing, data analyst review, printing and mailing on IRS-approved paper, electronic recipient delivery, and corrections at no per-correction fee.

Still weighing your options? Schedule a free transition consult and we’ll help you figure out which approach fits your volume and resources, even if the answer is to do it yourself. Have questions first? Browse our TAB1099 FAQs or read about our security and compliance standards.