Professional licensure in the United States
Fields that are regulated and licensed vary among individual states. Among regulated fields are health care professionals (medical doctors, nurses); psychologists; lawyers; teachers; engineers; social workers, occupational therapists, architects; tradesmen (plumbers, electricians), and certain service industry workers (bartenders; massage therapists; barbers).
It is now possible to verify an individual state license in all states online, via websites set up by each state government, by different agencies. Some private websites provide links to all such databases, in one location.
License standards and issues
Licensing standards can differ widely from state to state. Also, the fields and occupations which states require to be licensed may differ widely. Some states may require a written examination for a license, while others may require several years of field experience as a student or intern. Some states have license requirements which are fairly uncommon among other states; for example, four states require licensing for interior designers.  The State of Illinois requires four exams to become a "nail technician," or manicurist. 
There is often debate about the level and type of regulation needed. In Texas, there has been recent debate about state regulations which prohibit horse floaters from working on horses if they are not licensed veterinarians. 
Some standards and procedures are the product of state boards working together. For example, the United States Medical Licensing Examination (USMLE) is a medical exam which was created by the Federation of State Medical Boards.
Illegal immigrants are not allowed to receive state or local public benefits, which includes professional and commercial license.
- Of Horse teeth and liberty, The Economist, 10/27/07.
- (225 ILCS 410/) Article IIIC, Nail technicians, Section 3C-7, Illinois State Law: Barber, Cosmetology, Esthetics, and Nail Technology Act of 1985.
- 8 U.S.C. § 1621
- List of state verification sites, at noah-health.org. (New York Online Access to Health.)
- List of state verification sites, especially for medical licenses, at circare.org (Citizens for Responsible Care and Research)
Samples of search sites
- Illinois state site - features pull-down menu, listing all licensed professions