> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neynar.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Follow NFT Owners on Farcaster Using Neynar

> Comprehensive tutorial on how to automatically follow all Farcaster users who own specific NFTs like CryptoPunks. Learn to build Web3 social features by combining Farcaster social graphs with NFT ownership data using Neynar's powerful APIs.

## How to Follow Farcaster Users Owning a Specific NFT

This guide demonstrates how to follow Farcaster users who own a specific NFT.

Check out this [Getting started guide](docs/getting-started-with-neynar) to learn how to set up your environment and get an API key.

Before all that, initialize Neynar client:

```javascript Javascript theme={"system"}
// npm i @neynar/nodejs-sdk
import { NeynarAPIClient, Configuration } from "@neynar/nodejs-sdk";

// make sure to set your NEYNAR_API_KEY .env
// don't have an API key yet? get one at neynar.com
const config = new Configuration({
  apiKey:process.env.NEYNAR_API_KEY,
});

const client = new NeynarAPIClient(config);
const signer = process.env.NEYNAR_SIGNER;
```

First, we need to get the addresses owning Milady. We can use the [Alchemy NFT API](https://docs.alchemy.com/reference/getownersforcontract-v3) to get the addresses of users who own the NFT.

```javascript Javascript theme={"system"}
const getAddr = async (nftAddr: string): Promise<string[]> => {
  const apiKey = process.env.ALCHEMY_API_KEY;
  const baseUrl = `https://eth-mainnet.g.alchemy.com/nft/v3/${apiKey}/getOwnersForContract?`;
  const url = `${baseUrl}contractAddress=${nftAddr}&withTokenBalances=false`;

  const result = await fetch(url, {
    headers: { accept: "application/json" },
  });
  const data = await result.json();
  return data.owners;
};

// milady maker contract address
const nftAddr = "0x5af0d9827e0c53e4799bb226655a1de152a425a5";
const addrs = await getAddr(nftAddr);
```

Next, get Farcaster FIDs of each address, then filter out any undefined values.

```javascript Javascript theme={"system"}
const fidLookup = async (addrs: string[]) => {
  const fids = await Promise.all(
    addrs.map(async (addr) => {
      try {
        const response = await client.fetchBulkUsersByEthOrSolAddress({addresses:addr});
        return response ? response.result.user.fid : undefined;
      } catch (error) {
        return undefined;
      }
    })
  );
  return fids.filter((fid) => fid !== undefined);
};

const fids = await fidLookup(addrs);
```

Then, we can use the [Follow user](ref:follow-user) endpoint to follow each user.

```javascript Javascript theme={"system"}
const result = await client.followUser({ signerUuid:signer, targetFids:fids});
console.log(result);
```

Example output:

```json theme={"system"}
{
  "success": true,
  "details": [
    {
      "success": true,
      "target_fid": 132
    },
    {
      "success": true,
      "target_fid": 78
    },
    {
      "success": true,
      "target_fid": 4262
    },
    {
      "success": true,
      "target_fid": 3602
    },
  ]
}
```

That's it! You can now follow users who own a specific NFT easily with the Neynar SDK.

<Info>
  ### Ready to start building?

  Get your subscription at [neynar.com](https://neynar.com) and reach out to us on [Slack](https://neynar.com/slack) with any questions!
</Info>