I've been doing free pentesting on a lot of the new casinos posted on here, and I've noticed that at least 1 in 3 will have major vulnerabilities.
Please do NOT launch a business that operates with other peoples funds if you have no idea how (An example) basic input validation works.
If you are serious about your casino, then please do look into hiring a professional pentester.
Had to get this off my chest as the amount of new casinos with shitty security is skyrocketing.

This also serves as a PSA to users; Please use your brain when picking places to spend your hard earned cash. You might end up with nothing because the sites bankroll got ripped.

(If you've got a different view on this topic, then feel free to keep it to yourself)