Wallet, deposit and withdrawal management system or APIs What are the most popular solutions to create a website where a user can register, deposit crypto (not only bitoin, but all major coins, e.g. ETH, BCH, XRP, XLM, DASH, EOS etc.), receive a mail confirmation on payment confirmed, withdraw etc.?

Do you think the best is to use your own custom solution (and install the relative full nodes of the coins you want to support and use their APIs to manage the wallets) or there are robust and well known software solutions to manage user deposit?

If so, can you list a few solutions one can use to create a website to accept crypto deposits?

Requirement would be, have an address for each customer, or in case of XRP &amp; XLM, have a specific tag associated to the customer. Just like crypto exchanges work.

So far I found coinpayments.net, but from the first sight it doesn't seem to be what I'm looking for....
Although certain coins have a few available API providers (such as BitGo for Bitcoin), any sane and security conscious company should elect to run their own nodes for each supported currency, manage their own keys, and have their own wrapper to handle deposits and withdrawals by interacting with the nodes.

This is especially relevant for coins like Monero and ZCash, where third party API providers may not be able to view transactions related to your business at all due to privacy protocols.

Once you have the infrastructure in place, the flow you described is essentially correct - you assign an address (or address+memo) to a user, and treat all incoming deposits to that address as coins belonging to that user.