user2751: Does the bitcoin-core client have any RPC API to query the key pool? I have certain bitcoin address which I want to check if the wallet has access to (either via private key or via HD-private key derivation).
Is there a way to programmatically check this? I was going to use signmessage but that would need me to unlock the wallet with the passphrase first.

user208: Use validateaddress [address].
It will give you all information about that address, including whether it has the private key (it will "ismine" : true and "iswatchonly" : false.

2751: <p>Does the bitcoin-core client have any RPC API to query the key pool? I have certain bitcoin address which I want to check if the wallet has access to (either via private key or via HD-private key derivation).</p>

<p>Is there a way to programmatically check this? I was going to use <code>signmessage</code> but that would need me to unlock the wallet with the passphrase first.</p>
 208: <p>Use <code>validateaddress [address]</code>.</p>

<p>It will give you all information about that address, including whether it has the private key (it will <code>"ismine" : true</code> and <code>"iswatchonly" : false</code>.</p>
