CSVIRIS CSV Tool

IRIS glossary

The IRS uses a lot of short forms around IRIS. Here is what each one means for someone filing 1099s.

IRIS
Information Returns Intake System, the IRS system for e-filing Forms 1099 and other information returns. From the 2027 filing season it replaces FIRE completely.
IRIS Taxpayer Portal
The free IRIS website where you key in forms or upload a CSV file. It takes 250 records and 100KB per CSV, and submits up to 100 forms at a time.
IRIS A2A (Application to Application)
The IRIS channel for software. It takes XML transmissions of up to 100 MB and needs its own TCC.
FIRE
Filing Information Returns Electronically, the older IRS e-file system that took fixed-width text files. Its last filing day is November 19, 2026.
Publication 1220
The IRS specification for FIRE files: 750-character records (T, A, B, C, K and F records).
Publication 5717
The IRIS Taxpayer Portal User Guide. Rev. 9-2026 covers the 2027 filing season.
Publication 5718
The IRIS A2A specification for software developers.
TCC (Transmitter Control Code)
A 5-character code that identifies who files. IRIS Taxpayer Portal TCCs start with D and are separate from FIRE and A2A TCCs.
Issuer
The business that made the payments and files the returns. Also called the payer, or the filer on some forms.
Transmitter
A TCC role for filing for more than one business, such as a CPA or bookkeeper filing for clients.
Responsible Official (RO)
The person who submits and signs the IRIS TCC application with a 5-digit PIN.
Recipient
The person or business that received the payment. Also called the payee.
TIN
Taxpayer Identification Number. In IRIS CSVs it is written with dashes: XX-XXXXXXX for an EIN, XXX-XX-XXXX for an SSN, ITIN or ATIN.
EIN
Employer Identification Number, the TIN of a business. The IRIS TCC application requires one.
SSN
Social Security Number, the TIN of most individuals.
ITIN
Individual Taxpayer Identification Number, for individuals who cannot get an SSN. It starts with 9.
ATIN
Adoption Taxpayer Identification Number, a temporary TIN for a child in a pending adoption.
QI-EIN
The EIN of a qualified intermediary, used on some forms such as 1042-S.
UND
The TIN type for an undeterminable TIN. The number is written as 9 digits without dashes.
Name Type
B for a business name or I for an individual. Type I requires first and last name, and type B requires business name line 1.
Name control
The first four characters of a surname or business name, used by the IRS to match names and TINs. FIRE files carried it in the B record.
CF/SF
The Combined Federal/State Filing program, through which the IRS forwards returns to participating states. Your TCC must be enrolled.
Template Formatting Guidelines
IRS documents, one per form and tax year, that list every CSV column with its required flag and formatting rules.
Accepted
Every return in the transmission passed IRS checks.
Accepted with Errors
The IRS took the returns, but some data failed a business rule, for example a name/TIN mismatch (SHAREDIRFORM014 or 015) or a missing payer phone (S1H001).
Partially Accepted
Some returns in a transmission were rejected. File a replacement for those within 60 days.
Rejected
Nothing in the transmission was accepted. Fix it and file again as a replacement within 60 days.
Receipt ID
The ID IRIS gives a submitted transmission. Keep it to track status and corrections.
Business rule
An IRS check run after submission, identified by a code such as S1H001 or SMF018.
One-step correction
Fixes a wrong amount, name, TIN or code on a form already accepted.
Two-step correction
Fixes a return filed on the wrong form type: zero out the wrong form, then file an original on the right one.
Replacement
A resubmission of a rejected transmission. File it within 60 days of the rejection.
Form 8809
Application for Extension of Time to File Information Returns. The 30-day automatic extension is not available for 1099-NEC.
Form 15397
Application for Extension of Time to Furnish Recipient Statements, accepted in IRIS from tax year 2026.
Form 1096
The paper transmittal form. It is not needed when you e-file through IRIS.
Backup withholding
Federal tax withheld from a payment when the payee did not give a correct TIN. A 1099 is required whenever it applies, whatever the amount.
TIN Matching
A free IRS e-Services program that checks payee names and TINs before you file.
TTOC
Treasury Tipped Occupation Code, a new 2026 box on Forms 1099-NEC (1c) and 1099-MISC (13b) for workers who receive tips.

See also IRIS error codes and IRIS vs FIRE.

Sources

Last reviewed November 1, 2026.

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