My personal suggestion is to make it as the users’ initials with a number after.
For example, Adam Dodds is #1 user, so would be AD1. If Viktor Nebehaj is #2, he would be VN1. Number 1 after the initials remains because the initials alone will still keep the user’s reference unique. This will avoid numbers such as tens of millions (we know it will only take a few years to get to those).
Therefore, whenever #59 user named Adam Drums will be registered, he will be AD2 (on the proviso that no other users between #1 and #58 had AD initials). Mine would be VK1 unless there is any other VK before #20. And so forth.
Benefits are the following:
The user will never forget their initials
The user will most likely be able to remember up to 3-5 digits of their ID.
I must admit, I thought so too. If I remember rightly, Lloyds do and so do Monzo (as already stated above) and I was pretty sure it was standard practice. It’s amazing how little things like this banks still can’t get right
The bank remembering it is great if you’ve entered it correctly, but if you enter it incorrectly and the bank remembers it that has the potential to make the problem worse. Some users will see their payment hasn’t gone through and will make the payment again, causing extra work for the Freetrade team to manually sort out.
Making it easy for users to enter it correctly will reduce these kinds of problems. It will also make the user feel less intimidated by the app if they don’t have to pass a difficult memory test right off the bat.
I recognise that once you’re in and set up this stops mattering, but Freetrade will do better if there isn’t this kind of choke point filtering out some of their users before they become customers.
Short term memory is good for about seven letters or nine digits for about 10 to 15 seconds. If a person has to store and retrieve other letters or digits during that period then you can forget it (hah). Best to make it as simple as possible.