General fanager and cap geek before them do a lot of work in this area. They need to know all 30 teams roster and cap hit for each and every single day. They need to know bonus terms and get bonus overages exactly right.
They've really made it easy for us. I have no doubt there's the odd mistake here and there but they are 99% spot on especially for the cap teams which is really important. For teams like the Jets it's less important.
Was truly very sad to see CapGeek shut down. GeneralFanager has been a good replacement though getting better every day. Definitely my goto site for any cap related info.