Obtain an IRS e-Services account and enroll in the TIN Matching program at irs.gov/e-services; complete identity proofing via the IRS online registration process, which uses Login.gov.
If integrating programmatically via an API client ID (for e-Services, TDS, and related services), apply through the IRS Get an API Client ID page and follow the OAuth 2.0 credential issuance process.
For interactive bulk matching (up to 100,000 name/TIN pairs), submit the file through the e-Services bulk TIN matching interface; results are returned within 24 hours with a match/no-match/mismatch flag for each record.
For real-time interactive matching (up to 25 pairs per session), use the e-Services online TIN matching tool and record the response codes: a code 0 indicates a match, non-zero codes indicate specific mismatch or invalid TIN conditions.
Log each TIN match attempt, the response code, and the date for backup withholding determination; a no-match result triggers a B-notice obligation to solicit a corrected Form W-9.
Do not store the full response in a way that enables use outside the scope of backup withholding compliance; IRS TIN matching terms of service restrict use to payer B-notice and 1099 filing workflows.
Known gotchas
TIN Matching is available only to authorized payers (filers of 1099-B, 1099-DIV, 1099-INT, 1099-MISC, 1099-OID, and 1099-PATR); other use cases are not permitted under the TIN matching program terms.
Bulk TIN matching results are not real-time; scheduling bulk submissions before filing deadlines and accounting for the up-to-24-hour processing window is essential to avoid missed correction deadlines.
A TIN match result indicates only that the name and TIN combination is consistent with IRS records at the time of query; it does not confirm current filing status, entity type, or the absence of backup withholding flags.
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