well.. martingale works always but it depends on your balance and of course on gambling site 
if you have good bankroll management it and play trusted Provably fair gambling site it will work 
but its always to invent some good your own strategy (depending on Site you play) good luck with it mate
if you have good bankroll management it and play trusted Provably fair gambling site it will work but its always to invent some good your own strategy (depending on Site you play) good luck with it mate You are wrong. Martingale not always works, yes it works sometimes but when the long losing streak comes it will bust your bankroll for a few satoshi return by your basebet