Online casinos that have strong regulation will only use licensed casino software companies, which means they will be heavily audited by third parties like eCOGRA, which tests things like random number generators for fairness. There are two main types of software that you will find at online gambling sites, with these being the licensed and regulated games from companies like Microgaming and Playtech, while the other is from companies like RealTime Gaming, which allows online casinos to alter the source code of their games — in essence they don't provide player assurances after the game has left their grasp. Instead when playing at a RTG casino, or one like it, you should be sure that site you are playing at has a strong reputation, with good reports from players.