I have read several responses to various questions SE. Some responses partially respond to the question so I was hoping to get your help to bridge my gaps in understanding.

  1. Does every single node on the network validate the transactions in the mempool?

  2. Once the block is created and the transactions are included within the block...

a) What does it mean to say that the block and its transactions are also validated by the nodes? Isn't the block validated simply because the miner already solved the block?

b) What is the validation process for the newly solved block? and the transactions within it?

  1. I thought that consensus rules mean that every node follows the same rules for verifying transactions. Why does Euromoney.com state just a majority of nodes needs to agree that the transaction is valid? Is what they have stated incorrect?

    Euromoney.com states "the decision to add a transaction to the chain is made by consensus. This means that the majority of “nodes” (or computers in the network) must agree that the transaction is valid. The people who own the computers in the network are incentivised to verify transactions through rewards."

Thank you in advance.

1 Answer 1


Every node validates all transactions and blocks that it receives.

No node trusts miners to perform validation for them. Miners create confirmations in the form of blocks (which nodes validate). There is an important distinction between confirmation and validation (AKA verification). Everyone validates everything they can. Only miners confirm transactions but those confirmations are validated by nodes and can be discarded.

There is no voting in the Bitcoin network. The notion of consensus just means that groups of nodes that apply different rules will eventually form distinct networks and fork the blockchain. There is no specific coordination of this and no measuring of percentages. If a group of nodes all apply the same rules they will all arrive at the same view of what data is valid and part of each node's copy of the blockchain. Each node's copy will essentially be the same as that of everyone other node that applies the same rules.

Euromoney.com is evidently not a good source of accurate information about Bitcoin. The last sentence you quoted is, at best, misleadingly imprecise. In reality it is the people who own the mining hardware who are incentivised to confirm transactions through rewards.

  • Thank you for acknowledging that what I read on the site was not accurate. I was having trouble reconciling two different concepts. I've read some of your responses to other questions. I appreciate your help. A follow up question. What does it mean when a node validates a block? (Does that mean it checks whether the block was actually accurately solved?)
    – HeyDoeFarm
    Apr 13, 2022 at 21:01
  • Yes every node checks that the block's contents meet all the rules including that the hash of the block must be a smaller number than the current target. Apr 13, 2022 at 21:04
  • Miners specify an order for the transaction, by placing them in a block. But the content of each transaction can and should be validated by each node.
    – OptOut
    Jan 9, 2023 at 10:12

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