
In an audit, your client has to prove every exempt sale.

In Washington the seller has to prove a sale is exempt. Without the buyer's reseller permit or other exemption proof on file, the Department of Revenue treats it as a taxable retail sale and your client owes the sales tax on it, for up to four years back. Missing proof is one of the most common audit adjustments.
An exempt sale without proof is a taxable sale.
Customers come from your client's books.
Pick the customer and the proof. Sundry emails the customer a link that works for seven days. Send again issues a new link and cancels the old one.
The customer fills in the state's own form and signs it.
Sundry reads it against the form's requirements. When a buyer sends proof through Sundry's request link and Sundry can't read it, the buyer is asked for a clearer copy.
A proof marked Verified by Sundry is covered by the Sundry Guarantee.
For a small accounting or bookkeeping firm, exemption proof is scattered across every client. Sundry sends the request and reads what comes back. Each company's proofs are in one place, with what's waiting on a buyer listed first. Your staff step in only where a person is needed.
More clients. Not more hours.
A sale is exempt on the return only when a verified proof is in date at the sale. For a resale, Sundry allows the 120 days Washington gives to obtain it, as long as the proof's effective date is on or before the sale.
The Sundry Worksheet shows the exempt sales and how many are covered by a proof before your client signs off. Nothing goes forward until you approve it.
The guarantee
The Sundry Guarantee covers our determination and every proof we verify. If either is wrong and your client underpays as a result, we refund what you paid us for that return. See the Sundry Guarantee.
Sundry supports the Washington exemption proofs listed here: the state forms buyers sign, certificates the Department of Revenue issues, permits and other documents. Find yours by name, form number or statute.