W-9 onboarding

Catch W-9 mistakes before they hit your books

Upload any IRS Form W-9 from a new sub or vendor and PaidWrite verifies TIN format, signature, business classification, and backup-withholding status. The mistakes that cause 1099 errors at year-end — caught at onboarding.

Scan a document Read the W-9 mistakes contractors make — full guide

Why W-9s break at year-end and not at onboarding

  • ▲ A vendor checks "Individual" but enters an EIN. The classification mismatch shows up only when the IRS rejects your 1099.
  • ▲ The TIN field is one digit off. You issue a 1099 with the wrong TIN and get a CP2100 notice.
  • ▲ The form is unsigned, or signed but undated. The IRS treats it as missing.

How PaidWrite verifies a W-9

  • ✓ Validates the TIN format against the business classification (SSN for Individual, EIN for LLC/Corp/Partnership).
  • ✓ Detects backup-withholding status from the certification block.
  • ✓ Confirms the form is signed AND dated.
  • ✓ Flags Sole Proprietor name vs. business name mismatches that trip up 1099-NEC filings.

What you get

TIN format validation

SSN (9 digits, XXX-XX-XXXX) for individuals; EIN (XX-XXXXXXX) for entities. PaidWrite catches transposed digits and wrong format.

Classification cross-check

Flags when the business name suggests an entity but the box checked is "Individual" — or vice versa.

Backup-withholding flag

Surfaces when the certification is struck through (item 2), which means you must withhold 24%.

Signature + date check

Both required for the form to be valid IRS substantiation.

Frequently asked questions

Does PaidWrite store the SSN/EIN?
No. The TIN is validated in memory and never written to our database. The analysis result stores only "TIN format valid: yes/no" — not the number itself.
What W-9 versions are supported?
The current IRS revision (October 2018) and the prior 2014 revision. Older revisions trigger a "request a current W-9" warning.
Can I batch-process W-9s for a new project?
Yes — upload up to 25 at a time during onboarding sweeps.
Is this a substitute for collecting a real W-9?
No. PaidWrite verifies a W-9 you've already collected from a vendor. We don't generate or sign W-9s.

Educational reference. PaidWrite cites California statutes but is not a substitute for a licensed attorney on binding matters. See Disclaimer.