What's the difference between צדיקים and חסידים?
I assume that there is a difference because of Psalms 145:17. Also at the end of Nishmat Kol Chai where it says "uvdivrey tzadikim titbarach uvilshon chasidim titromam."
Also, the benediction in the Amidah "al hatzadikim ve'al hachasidim."