Compared to other cities in Hungary, security in Debrecen is at a fairly high level. Offenses against foreign tourists are considered extremely rare in this city.
The main danger for visitors to the city is pickpockets and scammers scurrying around the tourist-filled central city streets and markets. You should be especially careful with your belongings during festivals and celebrations.
The outskirts of Debrecen are the most dangerous neighborhoods. As for the city's central streets, you can walk along them even at night.