Importpubkey

importpubkey "pubkey" ( "label" rescan )

Adds a public key (in hex) that can be watched as if it were in your wallet but cannot be used to spend. Requires a new wallet backup.
Hint: use importmulti to import more than one public key.

Note: This call can take minutes to complete if rescan is true, during that time, other rpc calls
may report that the imported pubkey exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.
Note: Use "getwalletinfo" to query the scanning progress.

Arguments:
1. pubkey    (string, required) The hex-encoded public key
2. label     (string, optional, default="") An optional label
3. rescan    (boolean, optional, default=true) Rescan the wallet for transactions

Examples:

Import a public key with rescan
> bitcoin-cli importpubkey "mypubkey"

Import using a label without rescan
> bitcoin-cli importpubkey "mypubkey" "testing" false

As a JSON-RPC call
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "importpubkey", "params": ["mypubkey", "testing", false] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/