"Protecting" records by making IDs hard-to-guess just seems like putting the responsibility in the wrong place. If you're so worried about people getting their

"Protecting" records by making IDs hard-to-guess just seems like putting the responsibility in the wrong place. If you're so worried about people getting their hands on the wrong records, I'd be more worried about your lack of trust in the application that queries that database in the first place: remember, even if you do make the IDs hard to guess, your "untrusted application" might at some point decide to simply leak the entire table instead. There are much better solutions for this, like server-side prepared queries that do not simply return on an ID but rather as the result of a join, or just proper security practices in general, rather than reactively making something that was once guessed simply harder to guess. Also, something like an ID is in my experience something that will be referred to orally between two human beings when discussing a problem, like referring to user 6201 or discussing invoice 540567. When you switch to UUIDs you're basically also saying "no human will ever have to say this out loud".