Is it possible to process (stored in the same block) two successive transactions simultaneously?

'Two successive transactions' means that the second transaction's input is the first transaction's output.


1 Answer 1


Yes, multiple transactions building on each others' outputs can be in the same block. However, they have to be in the correct order inside of the block.

The order of transactions in a block can be freely chosen except for two rules: the coinbase transaction must be the first transaction, and parents must be before children. Note that the order of transactions in blocks is explicitly specified by the positions of the leaves of the Merkle tree.

  • 1
    Thanks for your reply. What is 'order'? The order in the merkle tree?
    – forfun
    Sep 6, 2017 at 6:23
  • The transactions are in a specific order (which corresponds to the positions of the leaves of the Merkle tree). Mostly the order is up to the miner, but Coinbase transaction must be first tx, and parents must be before children.
    – Murch
    Sep 6, 2017 at 6:29

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