The send payments input box has a pretty bad UX flaw. The example input value is 00.00, but as you start entering numbers the decimals disappear. Nearly every time I use it I end up entering 1000 when I mean 10.00.
The UI is particularly misleading here, but based on all other banking apps I would expect to need to fill the decimals. The least dangerous approach would be to require the decimals to be filled in - worst case you 1/100 of what you wanted to send, rather than 100x.
This also seems to be a fairly long standing issue:
I’m definitely not advocating specifically for making it so you need to add decimals, only so that the example input is more closely tied to what the user is going to type.
Although I agree it’s easier to not have the compulsory decimals, I do know a number of people who have accidentally sent the wrong amount due to this flaw. Definitely something MONZO should look at.