National Registry of Emergency Medical Technicians 
Go to: https://www.nremt.org/rwd/public/dashboard/check-cert-status

Note: The search results indicate the NREMT (National EMS Certification) status for the individual. NREMT certification is not the same as a license to practice. In some states it is possible to have a lapsed, expired, or inactive NREMT credential and a valid state issued EMS license. To verify an individual's license to practice, you must contact the State EMS Office: https://www.nremt.org/rwd/public/states/state-ems-agencies.