So I'm following a library containing the file named "ProtcolConstansts.php", there's one line confusing me

/** @var int Maximum length of transaction memo */
public const MAX_TX_MEMO_LEN = 32; // 32 bytes

What is Memo in Transaction?

  • 1
    Which library? Are you sure it is about Ethereum?
    – Ismael
    Jan 2, 2021 at 14:57

1 Answer 1


There is no such concept in Ethereum. Transactions don't have any "memo" feature, so it must be some custom functionality, probably in a smart contract.

My guess is that it's the length of some bytes variable, which is given as a parameter to a smart contract function.


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