Check Bitcoin address balance from blockchain I am a merchant that accepts bitcoins, and I'm building my own desktop client for receiving them in Java.

When I receive a transaction, I would like to be able to see in my client how much bitcoin is stored in the address that I am receiving from.

I have the full blockchain downloaded on my computer.

How can I access the balance of an address from the blockchain? I would like to be able to do this offline by accessing the blockchain stored on my hard drive.

Thanks in advance
Perhaps you can look at the source code of full-mode bitcoin implementations in Java, such as bitsofproof (BOF).

It seems bitcoinj also has a full-mode but it is experimental only and not really suitable for prod.

Hope this helps...