How to get a token mint address from a transaction signature in Solana web3

Question

How do get the token mint address from a transaction signature in Solana web3?

Here's an example. https://explorer.solana.com/tx/4y2zCnN1ciucLE6z91J7cQXz4skhCpoBJqhcecfuri5zp2NMSYejopTvGq2sYS9Ud5AkRirFkLXocZKdNfzWudG3?cluster=devnet

This is the transaction signature. 4y2zCnN1ciucLE6z91J7cQXz4skhCpoBJqhcecfuri5zp2NMSYejopTvGq2sYS9Ud5AkRirFkLXocZKdNfzWudG3

I want the token mint address so I can look up the metadata. DzAP4MvZNzV6zUrAW9wKXzDrpgRmEPa1QHhrSBEB823W

I can't figure out how to get the token mint from the transaction signature.

Answer 1

There are several ways you could do that.

Solution 1

You can check the instruction #5 i.e the Candy Machine: Mint instruction (code here) the mint account is the account number 6 (code) and the metadata account is the account number 5 (code)

In JS it would be something like:

import { Connection, clusterApiUrl } from "@solana/web3.js";

const connection = new Connection(clusterApiUrl("devnet"));

async function getMint(tx: string) {
  const result = await connection.getTransaction(tx);

  const metadaIndex = result?.transaction.message.instructions[4].accounts[4];
  const mintIndex = result?.transaction.message.instructions[4].accounts[5];

  if (!metadaIndex || !mintIndex) {
    throw new Error("Account not found");
  }

  return {
    mint: result?.transaction.message.accountKeys[mintIndex],
    metadata: result?.transaction.message.accountKeys[metadaIndex],
  };
}

getMint(
  "4y2zCnN1ciucLE6z91J7cQXz4skhCpoBJqhcecfuri5zp2NMSYejopTvGq2sYS9Ud5AkRirFkLXocZKdNfzWudG3"
);

And it will return

{
  mint: 'DzAP4MvZNzV6zUrAW9wKXzDrpgRmEPa1QHhrSBEB823W',
  metadata: '4YR5CeLEZCF7qVpvHQfYoL84gQQb6uj5sGbaAqP2Eqgj'
}

Solution 2

Another solution would be to look at the instruction #4 i.e the Token Program: Mint To and extract the first key

In JS it would be

import { Connection, clusterApiUrl } from "@solana/web3.js";

const connection = new Connection(clusterApiUrl("devnet"));

async function getMint(tx: string) {
  const result = await connection.getTransaction(tx);

  const mintIndex = result?.transaction.message.instructions[3].accounts[0];

  if (!mintIndex) {
    throw new Error("Account not found");
  }

  return {
    mint: result?.transaction.message.accountKeys[mintIndex],
  };
}

getMint(
  "4y2zCnN1ciucLE6z91J7cQXz4skhCpoBJqhcecfuri5zp2NMSYejopTvGq2sYS9Ud5AkRirFkLXocZKdNfzWudG3"
);

And it will return

{ mint: 'DzAP4MvZNzV6zUrAW9wKXzDrpgRmEPa1QHhrSBEB823W' }