Do the notifications from walletnotify and blocknotify are sent during the wallet synchronization or at the end? Say the wallet was offline for 100 blocks and when started: will it send the notifications after the each block it downloads and verifies and so all the relevant transactions in them or will it send them at the end? I would assume it sends them as it gets them, so then how would I resolve these properly if all the incoming request at that time are blocked?

1 Answer 1


Refers to Bitcoin Core 0.17:


Will be executed at the time when a transaction gets added to the wallet. If your wallet is 100 blocks behind and in those 100 blocks you have 2 transaction in each block, the wallet notify script will be called twice per block (== 200 executions during the 100 block catch up).

Only valid blocks (valid transaction) will result in a wallet-notify call.

Will also be called when a mempool transactions (unconfirmed transaction) was added to the wallet (and therefore relevant to the wallet)


Will be executed when a block gets connected to the active chain and before WalletNotify.

Consider taking a closer look at Bitcoin Cores ZMQ API that allows more efficient process interaction (wallet/block notify spawn a process on each call).

  • Thanks for the quality response. It's worth noting that ZMQ does not guarantee responses, for situations where you must know about transactions it is more suitable to poll.
    – Claris
    Jan 31, 2019 at 22:35

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