How to Get a Contract's First Transfer Event

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API Endpoint

This tutorial uses the alchemy_getAssetTransfers endpoint.

If you just need the script for this tutorial refer to the below Recipe or continue reading for more

One of the best ways to study a smart contract is to look at its transfer events. In this tutorial, we will query the very first transfer event of the BAYC smart contract. However, you are welcome to use any contract address you are interested in!

See the following for use cases for retrieving a contract's first transfer event:

• Finding the first addresses to interact with a contract (e.g., the first address to mint a Bored Ape).
• Tracking the first interaction an address had with a smart contract.
• Verifying whether a contract facilitated transfers before a certain date.

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Note:

If you already completed "How to get a contract's last transfer event", you may skip the setup and installation steps.

Install Node.js

Head to Node.js and download the LTS version.

You can verify your installation was successful by running npm -version in your macOS terminal or Windows command prompt. A successful installation will display a version number, such as:

6.4.1

Setup Project Environment

Open VS Code (or your preferred IDE) and enter the following in a terminal:

mkdir contract-transfers
cd contract-transfers

Once inside our project directory, initialize npm (node package manager) with the following command:

npm init

Press enter and answer the project prompt as follows:

package name: (contract-transfers)
version: (1.0.0)
description: 
entry point: (index.js)
test command: 
git repository: 
keywords: 
author: 
license: (ISC)

Press enter again to complete the prompt. If successful, a package.json file will have been created in your directory.

Install Alchemy's SDK

Alchemy's SDK allows us to efficiently interact with Alchemy's endpoints and make JSON-RPC requests.

Ensure you are inside your project folder, then type the following command in terminal:

npm install alchemy-sdk

Get Contract's First Transfer Event

In this section, we will use Alchemy's Transfer API to retrieve the contract's first transfer event. The Alchemy SDK allows us to call the alchemy_getAssetTransfers function and filter transfers by passing in the following object parameters:

For reference, here is an example of how the above parameters could be passed into getAssetTransfers:

alchemy.core.getAssetTransfers({
    fromBlock: "0x0",
    toBlock: "latest",
    contractAddresses: ["0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d"],
    excludeZeroValue: true,
    category: ["erc721"],
  });

To get started finding a contract's first transfer, let's create a file inside our project folder named FirstTransfer.js and add the following code to utilize the alchemy_getAssetTransfers endpoint:

// Setup: npm install alchemy-sdk
import { Alchemy, Network } from "alchemy-sdk";

const config = {
  apiKey: "<-- ALCHEMY APP API KEY -->",
  network: Network.ETH_MAINNET,
};
const alchemy = new Alchemy(config);

const getFirstTransfer = async () => {
  // Calling the getAssetTransfers function and filters using the following parameters
  const allTransfers = await alchemy.core.getAssetTransfers({
    fromBlock: "0x0",
    contractAddresses: ["0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d"], // You can replace with contract of your choosing
    excludeZeroValue: true,
    category: ["erc721"],
  });

  // printing the first indexed transfer event to console
  console.log("First Transfer:", allTransfers.transfers[0]);
};

getFirstTransfer();

Above, we created an async function called getFirstTransfer. To learn more about how what it does, view the commented notes above.

To use your script, run the following command in your terminal:

node FirstTransfer.js

If successful, you should see the following transfer object in your output:

First Transfer: {
  blockNum: '0xbb933a',
  hash: '0xcfb197f62ec5c7f0e71a11ec0c4a0e394a3aa41db5386e85526f86c84b3f2796',
  from: '0x0000000000000000000000000000000000000000',
  to: '0xaba7161a7fb69c88e16ed9f455ce62b791ee4d03',
  value: null,
  erc721TokenId: '0x0000000000000000000000000000000000000000000000000000000000000000',
  erc1155Metadata: null,
  tokenId: '0x0000000000000000000000000000000000000000000000000000000000000000',
  asset: 'BAYC',
  category: 'erc721',
  rawContract: {
    value: null,
    address: '0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d',
    decimal: null
  }
}

Congratulations, you've successfully retrieved the first transfer event in the BAYC contract!

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