TIN Compliance is a free reference site from TIN Comply, a vendor onboarding platform for IRS TIN matching and sanctions screening, based in Austin, Texas. Every guide is written and reviewed by the people who build TIN Comply.
Who writes the guides
The team has spent over fifteen years building and running the leading U.S. 1099 and IRS TIN matching platform, used by more than 10,000 companies including roughly half the Fortune 100. They were also appointed by the U.S. Treasury to serve on the IRS Electronic Tax Administration Advisory Committee. The guides come from the questions those companies asked, year after year, about W-9s, mismatches, B-Notices and penalty notices.
What is here
Everything on the site is free and needs no signup. It follows the information-reporting cycle, from onboarding a vendor to answering a penalty notice.
- Guides. 128 long-form guides, from W-9 solicitation rules to how the IRS reviews a 972CG response.
- Tools. 49 tools that run in your browser: B-Notice and solicitation deadline calculators, 972CG and backup withholding estimators, TIN format and name control checks, and the IRIS CSV checker.
- Templates. 42 letters and checklists, including the First and Second B-Notice letters from Pub 1281, W-9 solicitation letters and reasonable-cause statements.
- Forms and notices. 48 federal form pages, and one page for each of 90 IRS notices with the deadline and what to do.
- Filing. The IRIS filing hub, the FIRE to IRIS migration, the bulk TIN matching walkthrough with screenshots of the live IRS system, and a verified page for every state and D.C. on state 1099 filing requirements.
- Foreign payees. W-8s, chapter 3 and FATCA for payers, and treaty rates for 65 countries.
- By reader. 18 industry pages and 5 pages written for payees.
- Reference. The 2026 figures and an interactive compliance calendar with .ics download.
How we write these guides
Each guide is written from the primary sources (the Internal Revenue Code, Treasury regulations and IRS publications named at the top of the page) and checked against current IRS figures before publication. We state the dates, deadlines and dollar amounts the IRS uses rather than paraphrasing them, and we note the year each figure applies to. Guides carry the date they were last reviewed.
The body of every guide is vendor-neutral. Where TIN Comply is relevant we say so in a clearly labeled block at the end, and never in the guidance itself.
Corrections
If a figure is out of date or a rule has changed, tell us at support@tincomply.com and we'll fix it and note the change.
Not advice
These guides are general information about U.S. information-reporting requirements. They are not legal or tax advice, and your facts may differ. Confirm current requirements in IRS publications or with your adviser before acting. Our terms of use cover quoting and reusing the guides, calculators and templates.
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