<p>Generally, the replacement rules employed by Bitcoin Core specify that a replacement must both exceed the original transaction in feerate as well as in absolute fees.</p>
<p>A likely explanation could be that while your node saw the higher feerate transaction first, the miner that found the block had seen the original, lower feerate transaction first and when they authored a block, you learned about the lower feerate transaction from the block. Another reason could be that the winning transaction was accompanied by a child transaction which overall made parent and child more attractive than what you considered the better transaction.</p>
<p>These are only guesses, and there are a number of other scenarios in which a partial view of the overall situation could look like what you describe. If you want a more specific answer, please share the transactions in question.</p>

CC BY-SA 4.0
2024-05-20T13:06:23.643Z
2024-05-20T19:55:37.857Z
2024-05-20T19:55:37.857Z
Murch
<p>I have seen a tx A get replaced by a tx B, where B had a lower fee and feerate than A and it was broadcasted later. How is it possible?</p>
<p>These are the txs details:</p>
<ul>
<li>Tx A: segwit,  ̶t̶a̶p̶r̶o̶o̶t̶,  ̶R̶B̶F̶</li>
<li>Tx B: segwit,  ̶t̶a̶p̶r̶o̶o̶t̶,  ̶R̶B̶F̶, Full RBF</li>
</ul>
<p>Can anyone help me understand it, please?</p>

CC BY-SA 4.0
2024-05-17T12:23:50.977Z
Could you share the transactions you're talking about?
Antoine Poinsot
<transaction-fees><segregated-witness><replace-by-fee>
How can a replace occur with a tx with lower fee and feerate?
user80100
# How can a replace occur with a tx with lower fee and feerate?

(Asked by: username_0 on 2024-05-17)

I have seen a tx A get replaced by a tx B, where B had a lower fee and feerate than A and it was broadcasted later. How is it possible?

These are the txs details:

* Tx A: segwit, ̶t̶a̶p̶r̶o̶o̶t̶, ̶R̶B̶F̶
* Tx B: segwit, ̶t̶a̶p̶r̶o̶o̶t̶, ̶R̶B̶F̶, Full RBF

Can anyone help me understand it, please?

**Tags:** transaction-fees, segregated-witness, replace-by-fee

> **Comments:**
> **username_1**: Could you share the transactions you're talking about?  

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## 1 answers

### Answer by username_2 on 2024-05-20. Score: 1 | Accepted answer

Generally, the replacement rules employed by Bitcoin Core specify that a replacement must both exceed the original transaction in feerate as well as in absolute fees.

A likely explanation could be that while your node saw the higher feerate transaction first, the miner that found the block had seen the original, lower feerate transaction first and when they authored a block, you learned about the lower feerate transaction from the block. Another reason could be that the winning transaction was accompanied by a child transaction which overall made parent and child more attractive than what you considered the better transaction.

These are only guesses, and there are a number of other scenarios in which a partial view of the overall situation could look like what you describe. If you want a more specific answer, please share the transactions in question.


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