You can check it yourself in a few minutes. Washington L&I keeps a public contractor lookup where you enter the business name or license number. It shows the registration status, the bond amount, the insurance policy, and any claims people have filed against the bond. Look for a registration that has stayed active rather than one that lapsed and came back last week, and confirm the business name on the license matches the name on your contract exactly.
Two things worth adding. Ask the insurer to send you the certificate of insurance directly instead of taking a PDF the contractor forwards. Then confirm the bond is current, since that bond is what stands behind you if the work goes sideways.
This works the same way for a commercial construction company bidding for a tenant improvement and for residential remodeling contractors quoting a kitchen. Registration is registration. The size of the job does not change what you check before money changes hands.
