Last but not least, you need to give good reports and controls to your direct customers. Access to live data should be highly restricted. As a general rule, casinos don't keep their business in the cloud. Make sure your backend is modular enough that you can do your own authentication and monetary transactions, or act as a client for your customer's own authentication/transaction mechanisms. Integrations become very important very fast. Code your own Mersenne Twister or something just as (or more) sophisticated. Good random number generators are also a top priority, and most languages have very low-end, predictable ones. Your need people who knows their probability, and hopefully these will be the coders themselves. Casinos are a volume business and on average they do keep very low percentages of any single bet. Yes, you need a good understanding of the games, and I don't mean just the rules: you need to understand how the game works from a probability standpoint. Looks for certification bodies in pages like this one. Later on, measurable accountability became legally relevant, so we got our games certified. Bought books on the games, became knowledgeable on them. Played in live ones and observed closely. Worked for an online casino provider for more than two decades.
