The getblockheader RPC gets a block header with a particular header hash from the local block database either as a JSON object or as a serialized block header.
getblockheader "hash" ( verbose )
*bitcoin-cli help getblockheader
getblockheader "hash" ( verbose ) If verbose is false, returns a string that is serialized, hex-encoded data for blockheader 'hash'. If verbose is true, returns an Object with information about blockheader. Arguments: 1. "hash" (string, required) The block hash 2. verbose (boolean, optional, default=true) true for a json object, false for the hex encoded data Result (for verbose = true): { "hash" : "hash", (string) the block hash (same as provided) "confirmations" : n, (numeric) The number of confirmations, or -1 if the block is not on the main chain "height" : n, (numeric) The block height or index "version" : n, (numeric) The block version "versionHex" : "00000000", (string) The block version formatted in hexadecimal "merkleroot" : "xxxx", (string) The merkle root "time" : ttt, (numeric) The block time in seconds since epoch (Jan 1 1970 GMT) "mediantime" : ttt, (numeric) The median block time in seconds since epoch (Jan 1 1970 GMT) "nonce" : n, (numeric) The nonce "bits" : "1d00ffff", (string) The bits "difficulty" : x.xxx, (numeric) The difficulty "chainwork" : "0000...1f3" (string) Expected number of hashes required to produce the current chain (in hex) "nTx" : n, (numeric) The number of transactions in the block. "previousblockhash" : "hash", (string) The hash of the previous block "nextblockhash" : "hash", (string) The hash of the next block } Result (for verbose=false): "data" (string) A string that is serialized, hex-encoded data for block 'hash'. Examples: > bitcoin-cli getblockheader "00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09" > curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "getblockheader", "params": ["00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/