like we play on gambling site and want to withdraw our crypto then we just need to type the amount we need to withdraw and click on "withdraw" button. then our withdrawal request get approved in a second, and goes directly to the blockchain.
my question is what is the process of withdrawal on most of the sites, which is so fast and without any double spending or issue like that?
Withdrawal request on most casinos and exchanges are approved in the batches so there is no such thing called the approval happens in a second. But we had some casinos with instant withdrawal feature which charge more fee and only process our transaction but they are the one sending funds to users so they won't be double spending them unless the site is scam.
The process of withdrawal as of now withdrawal -> wait for approval -> onchain transaction (needs enough confirmation) -> balance will credit on the receiving end.