salary cap data
These Excel spreadsheets have been cobbled together using data from various sources, including the NFLPA and USA Today. They're certainly not 100% accurate, and in many cases aren't very complete. For some teams, like Cleveland, it's extremely difficult to find contract data. Teams like Washington, on the other hand, give out such ridiculous contracts that the players' agents make sure that everyone knows everything about them.
For each year outlined for each team, the spreadsheets offer base salaries, signing bonuses, roster bonuses, and salary cap charges for each player, along with totals by position, by unit, and for the entire team in each category. Entries for which I am uncertain, for which I couldn't find corroborating sources, or that are flat-out guesses are coded in pink on each spreadsheet. The 'notes' files available along with some of the spreadsheets contain extra details or contract information that pre-dates that in the spreadsheets themselves.