I'm fairly sure that those app-based credit scores are rough estimations. You get dinged if you do a "hard pull" check from the actual agencies themselves like Experian.
Nobody truly knows how it's calculated. But taking on debt, as in new lines of credit, makes it go down slightly, not paying on time makes it go down significantly, and paying on time makes it go up significantly. The prostrat is to take out a credit card, spend only about 20-25% of your total balance, and pay it off entirely every month.