Three states, three tools, one habit worth building
Washington, California and Florida each run their own online lookup for contractor licenses, and none of them charge a fee or require an account to use.[1],[2],[3]
The habit that matters is using one of them before you hire, not memorizing which state uses which exact search box.
A name is usually enough to start in any of the three, though having the license number handy, often printed on a bid or a truck door, narrows the result faster when a business name is common.
What a Washington result is really telling you
L&I's own advice once you land on a match: don't stop at 'active.' Confirm the business is bonded and insured, look for a clean safety record or corrected violations, and skim its history for lawsuits or license actions before you commit.[4]
What a California result is really telling you
A California match shows license status plus any disciplinary history, and lists the workers' compensation and insurance information CSLB has on file for that business.[5]
CSLB adds an in-person step too: request a look at the pocket license alongside a photo ID, and make sure the face in front of you actually matches it before work begins.[5]
What a Florida result is really telling you
In Florida, the letter in front of the license number carries real meaning: a C prefix means certified, cleared to contract anywhere in the state, while an R prefix means registered, limited to specific local jurisdictions.[6]
That distinction matters most if you're comparing a business based a bit outside your immediate area; a registered license from a neighboring jurisdiction may not actually cover work at your address. When in doubt, the lookup result itself will show which type applies, so there's no need to guess from the license number alone.
Reading a result you didn't expect
An active, current match is a reasonable first filter, not a full vetting; it confirms the state currently recognizes the business as licensed, and nothing about the quality of any specific past job.
A name that doesn't turn up at all, or comes back with a status other than active, is worth a direct conversation before you move forward. It isn't automatically disqualifying, since license files can lag a recent renewal, but it's a fair question to ask outright.
Save or screenshot the result you find, with the date you checked it. If a question ever comes up later about whether a business was properly licensed at the time you hired them, having your own record of that lookup is more useful than trying to recreate it after the fact.