<p>The first transaction who makes it into the mempool will be the one spending the output. And in case there is congestion on the blockchain and multiple transactions make it into different mempools (on different nodes), the one who is adopted in a block first will be the one spending the UTxO.</p>

CC BY-SA 4.0
2023-03-29T11:15:45.983Z
2023-03-29T11:15:45.983Z
George - APEX Stake Pool
<p>Let's assume we have some NFT minting drop with more than 1000s of participating buyers who try to spend the same output, all at the same time. How does the chain decide who gets to spend the output? Is it first-in (the buyer who submitted the tx first), completely random, or something else?</p>

CC BY-SA 4.0
2022-11-03T21:29:36.060Z
The first transaction who makes it into the mempool will be the one spending the output.
And in case there is congestion on the blockchain and multiple transactions make it into different mempools (on different nodes), the one who is adopted in a block first will be the one spending the UTxO.
George - APEX Stake Pool
CC BY-SA 4.0
2022-11-03T22:00:18.010Z
@George-APEXStakePool So as long as each person submits around the same time of a new block being minted, it's basically random which out of all the txs in the mempool will be included on-chain?
et97
CC BY-SA 4.0
2022-11-04T00:42:10.043Z
Not quite random, the first transaction that enters the mempool of the block producer chosen to create the next slot will win, Its not quite random, but it will effectively look like its random.
Erik de Castro Lopo
CC BY-SA 4.0
2022-11-04T00:43:41.177Z
Stake Pool Operators can figure out which future slot in the current epoch they are due to mint, but if you are not an SPO you will not be able to figure out which SP is next to mint a block.
Erik de Castro Lopo
CC BY-SA 4.0
2023-03-28T10:34:23.267Z
@George-APEXStakePool I think you should answer the question with what you said in this comment, for future references.
Falcon Stakepool
<utxo>
When multiple users try to spend the same output at the same time, who will get priority?
# When multiple users try to spend the same output at the same time, who will get priority?

(Asked by: username_0 on 2022-11-03)

Let's assume we have some NFT minting drop with more than 1000s of participating buyers who try to spend the same output, all at the same time. How does the chain decide who gets to spend the output? Is it first-in (the buyer who submitted the tx first), completely random, or something else?

**Tags:** utxo
> **Comments:**
> **username_1**: The first transaction who makes it into the mempool will be the one spending the output. And in case there is congestion on the blockchain and multiple transactions make it into different mempools (on different nodes), the one who is adopted in a block first will be the one spending the UTxO.  
> **username_0**: @George-APEXStakePool So as long as each person submits around the same time of a new block being minted, it's basically random which out of all the txs in the mempool will be included on-chain?  
> **username_2**: Not quite random, the first transaction that enters the mempool of the block producer chosen to create the next slot will win, Its not quite random, but it will effectively look like its random.  
> **username_2**: Stake Pool Operators can figure out which future slot in the current epoch they are due to mint, but if you are not an SPO you will not be able to figure out which SP is next to mint a block.  
> **username_3**: @George-APEXStakePool I think you should answer the question with what you said in this comment, for future references.  

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## 1 answers

### Answer by username_1 on 2023-03-29. Score: 2 | Accepted answer

The first transaction who makes it into the mempool will be the one spending the output. And in case there is congestion on the blockchain and multiple transactions make it into different mempools (on different nodes), the one who is adopted in a block first will be the one spending the UTxO.


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