Your contractors are already
Proofstack Verified.
The contractor you're about to hire has already documented their independence, uploaded their W-9, and confirmed their engagement history. Proofstack reduces your classification risk before the engagement starts.
What it means for you
Pre-verified. Pre-documented. Pre-compliant.
W-9 already on file
No chasing contractors for tax documents. Proofstack Verified contractors have their W-9 securely stored and ready to share the moment you start an engagement.
Independence documented
Every Proofstack Verified contractor has declared and documented their independence signals — mapped to the ABC test used in classification audits. The documentation exists before you need it.
Audit risk reduced
If your use of independent contractors is ever questioned, Proofstack Verified contractors come with pre-built compliance documentation: independence signals, confirmed engagements, and verified documents.
The Classifi platform
Access the verified contractor network
When you join Classifi, you get access to the Proofstack verified network — plus the full outside payroll intelligence platform.
Search verified contractors
Find Proofstack Verified and Elite contractors by skill, industry, location, and verification score. Every result comes with pre-verified documentation.
Start engagements with pre-verified workers
Begin an engagement knowing their W-9 is on file, their independence signals are documented, and their contractor status is supported by evidence.
Automatic W-9 collection
When you engage a Proofstack contractor, their W-9 is automatically available in your workspace. No requests, no follow-ups, no delays.
Independence signals for audit defense
If you face a classification audit, each contractor's independence signals are already documented against the ABC test prongs — ready for your audit defense.
Compliance intelligence across your workforce
Track off-payroll spend, monitor 1099 thresholds, manage reimbursement risk, and maintain audit-ready documentation across every contractor relationship.
Proofstack is built by Classifi — the outside payroll intelligence platform built by a former Indiana DWD state auditor. The same compliance expertise that powers employer audit defense now helps contractors document their independence.
Search verified contractors by state or industry
Find Proofstack Verified contractors in your state or industry — with documented compliance ready for your audit defense.
Reduce your contractor compliance risk
Join Classifi to access the Proofstack verified network, automate W-9 collection, and build audit-ready contractor documentation.