Proximity narrows the list; licensing narrows it further
Once you've found a window contractor near your ZIP, the next step is confirming they're allowed to do the work at all. All three states behind this site's listings publish their own public lookup tool, at no cost to use, for exactly this purpose.
Washington: L&I's contractor lookup
Washington's Department of Labor & Industries hosts a public search called Verify a Contractor, Tradesperson or Business. Look a business up by its name or its Washington UBI number, and the same search also accepts a contractor license number or a workers' comp account number if that's what you have on hand.[1]
L&I specifically recommends using the tool to confirm the license is active, that the business carries bonding and insurance, that its job sites have stayed clear of safety violations, and to review its history for lawsuits or past license violations before you hire.[2]
California: CSLB's license check
California's Contractors State License Board runs its Check a Contractor License tool, searchable by license number, business name, or the name of a person tied to the license.[3]
The record that comes back shows license status and any disciplinary history, along with the contractor's workers' compensation and insurance information. CSLB also suggests asking to see the contractor's pocket license and a photo ID in person, and checking that the person in front of you matches the license.[4]
Florida: the DBPR licensing portal
Florida's Department of Business and Professional Regulation runs the licensing portal's license search, searchable by name, license number, city or county, or license type.[5]
Pay attention to the license type code: a certified contractor, with a license number starting with C, can work anywhere in Florida, while a registered contractor, starting with R, is limited to the local jurisdictions where they're specifically registered.[6]
What to actually do with the number
Copy the exact license or registration number from a listing on this site and paste it into the matching state tool above rather than retyping it from memory. Confirm the status reads active, that the trade classification covers window or glazing work, and that the business name matches. A five-minute check before you dial is the cheapest insurance in the entire process.
Why proximity and licensing are two separate filters
A business can be the closest one to your ZIP and still be the wrong choice if its license doesn't cover the specific trade classification your job needs, or if its status has lapsed since the last time the underlying file was updated. Use distance to build a shortlist, then use the state's own tool to cut that shortlist down to businesses actually in good standing today.
The reverse is also true: a business several ZIP codes away with a clean, long-standing license record is sometimes the better call than the nearest name on the page, especially for a job where the replacement method or a specialty window shape calls for real experience.
What an active license does and doesn't tell you
An active status means the state currently allows that business to legally perform the licensed trade, and it typically means required bonding or insurance minimums are in place. It doesn't mean the state has inspected that business's actual workmanship, rated its work, or resolved every complaint ever filed against it. Reading whatever complaint or disciplinary history a state's tool makes public is a reasonable next step once you've confirmed the license itself is valid.