Is there a way to know from a Solidity contract that the current transaction is being simulated and is not going to be included in the blockchain? When I mention "from the contract" I mean from the contract of the token that is being exchanged.

I'm mostly referring to Uniswap token swap transactions.

I mean this type of simulation:

is it possible to run pending transactions on local node to see the outcome?

1 Answer 1


I don't think there is any property a contract could consult to know if it's live or a simulation. I also don't know of a reason for wanting to.

  • This should be a comment rather than an answer. Commented Sep 5, 2021 at 10:19
  • The answer is no. Commented Sep 5, 2021 at 19:39
  • I have proof that there are people who are doing that. Yes, it is possible, but I do not know how they do it. Commented Sep 6, 2021 at 18:10
  • I'm curious. Send it. Commented Sep 7, 2021 at 2:58

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