Returns the proof-of-work difficulty as a multiple of the minimum difficulty.
curl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"getdifficulty","params":[]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/
86388558925171.02
getchaintxstats
getmempoolancestors
bitcoind.app — Bitcoin Core RPC Reference