What are the difference between transaction chain in bitcoin and blockchain used in bitcoin?

Is it sufficient to say to each transaction refers to previous transactions in the transaction chain and also each transaction is part of a block which is a part of blockchain?

  • I've never heard of the term 'transaction chain' and I don't think this is the correct way to look at transactions. A transaction just uses an UTXO as input and puts out a new UTXO. The input becomes spent.
    – Lexus123
    Mar 29, 2018 at 14:32
  • In order to say that a transaction is valid like A pay B 5 BTC, A has to refer to the previous transaction where he receives equal to more than 5 BTC, right? So aren't all the valid transactions linked together like a chain?
    – n0unc3
    Mar 29, 2018 at 14:58
  • You may find this question and its answers useful: bitcoin.stackexchange.com/questions/49569/…
    – Jestin
    Mar 29, 2018 at 18:54

2 Answers 2


The blockchain consists of blocks which are collections of transactions. The blockchain is a linked list; each block has 0 or 1 previous blocks and 0 or 1 following blocks.

A transaction chain is a chain of transactions which is completely independent of the blockchain. A transaction chain is a directed acyclic graph; each transaction must have one or more previous transactions and zero or more following transactions.


There is a transaction hash chain. Each new transaction contains a back-link to the hash (often called the transaction ID) of the previous transaction. The blockchain contains blocks, each of which contains one or more transaction IDs. Each block on the blockchain maintains a back-link to the hash of the previous block on the blockchain. So you are correct: There are in fact two chains--a transaction chain and a blockchain.

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