receiving address with callback

[wpsd]

Hi,

I'm curious of how do blockchain, blockcypher, coinbase implement their receiving address public function

I understand we could use notifywallet function in the bitcoin-cli when a new address from wallet get a transaction, then we do all the forward magic ( or perhaps use "move" function ) to move the fund to designated address inside same wallet and initiate callback. To do that both address is required to be created inside our own wallet / account.

In case of blockchain and blockcypher they able to create a receiving address from any address not just the one that created by their own website.
And when you transfer to the receiving address two normal transaction happen one from outside to receiving address and second from receiving address to our address
Does that mean the they create a receiving address from their wallet account, which also mean during transaction the fund is routed to their wallet first before going to our own wallet ?
When the second transfer happen they pay for that additional fee, which sometime if too small will delay the transaction ...

[achow101]

Does that mean the they create a receiving address from their wallet account, which also mean during transaction the fund is routed to their wallet first before going to our own wallet ?

Yes, when you use the receive bitcoin callback, the coins get sent to the service before being forwarded to you, do it briefly is under the services control.