Building permits in Connecticut
2 jurisdictions, each with the department that issues, its portal and its phone number. Cities issue their own permits; counties cover unincorporated areas, which is the distinction that sends most contractors to the wrong office.
2 checked against the department's own page
Licensing
No general competency license; a Home Improvement Contractor registration is required for work on existing homes, and a New Home Construction Contractor registration for new builds (DCP).
Connecticut Dept. of Consumer Protection (DCP) — License Services Division