The Database Hattrick runs on is believed to be Microsoft SQL on a Hitachi server park. No one except the Hattrick Team knows for sure exactly what brands and number of servers that feeds the game. Hattrick has had several performance issues in the past pertaining to database related problems, among them the Black Friday. Twice has the HT's been forced to perform a rollback of a database backup to restore data from an earlier point in time, due to data being corrupted in the database.
During later years the database have been stable and better performing than it once was.