Construction Supervisor Licenses (CSL) can be checked through the Department of Public Safety at: https://madpl.mylicense.com/Verification/
Home Improvement Contractor Registrations can be checked through the Office of Consumer Affairs at: https://services.oca.state.ma.us/hic/licenseelist.aspx
Any contractor doing work on an owner occupied building of 1 or 4 dwelling units must be registered as a Home Improvement Contractor (HIC) when the value of the work is over $1000. The (CSL) is similar to a drivers' license while the HIC is similar to a car registration, in that you cannot drive a car without both. The CSL applies to the individual while the HIC applies to the business.