How to check a contractor's licence, by state
General-contractor regulation is not uniform. Of 51 jurisdictions, 29 license general contractors, 7 require registration without a competency examination, and 15 do not regulate general contracting at state level at all.
A registration is not a licence. Where a state registers rather than licenses, no competency examination is involved, and presenting one as the other would overstate what the state has verified.
Where a state sets a dollar threshold, a contractor working below it is lawfully unregistered. Absence from a register is not evidence of wrongdoing.
Method
Every fact on this site carries how it was established and when. 6 regimes were read from the agency's own page and 44 rest on two independent secondary sources agreeing. None yet rests on a statute. Thresholds carry a figure for 4 of the 36 jurisdictions where one can exist. Cells we have not verified say so rather than being left blank, and cells where the question does not arise say that rather than pretending to a gap.