Bitcoin extended public key transacaction listening

[talhamalik883]

Hey there. Guys i want to know about the extended public key transaction listening. I have a XPUB(Extended Public Key) from which i have generated a huge amount of address. Now what i want to do is to get transaction against generated address. BlockChain.info is doing this thing, i don't want to use that instead i want to know the way how they are doing this. Guys any help regarding this is appreciatable. Thanks.

[achow101]

They get it by deriving a lot of addresses from the xpub and then looking up the transactions related to those addresses. They follow the BIP 32 specification for deriving public keys from a parent public key.