gated-group

Building a gated group with NFT verification

To create a gated group chat using XMTP, you will need an admin bot within the group to manage member additions and removals. The admin bot will create the group, assign you as the admin, and then verify NFT ownership before adding new members.

Environment variables

WALLET_KEY= # the private key of admin bot
ENCRYPTION_KEY= # a second fixed or random 32 bytes encryption key for the local db


ALCHEMY_API_KEY= #alchemy api to check NFT ownership

You can generate random keys with the following command:

yarn gen:keys

Start the XMTP agent

Start your XMTP client and begin listening to messages. The bot responds to the following commands:

• /create - Creates a new gated group

if (message.content === "/create") {
  console.log("Creating group");
  const group = await client.conversations.newGroup([]);
  await group.addMembers([message.senderInboxId]);
  await group.addSuperAdmin(message.senderInboxId);

  await conversation.send(
    `Group created!\n- ID: ${group.id}\n- Group URL: https://xmtp.chat/conversations/${group.id}`,
  );
  return;
}

• /add <group_id> <wallet_address> - Adds a wallet to an existing group (if they own the required NFT)

// Handle /add command
if (message.content.startsWith("/add")) {
  const groupId = message.content.split(" ")[1];
  const walletAddress = message.content.split(" ")[2];

  const result = await checkNft(walletAddress, "XMTPeople");
  if (!result) {
    console.log("User can't be added to the group");
    return;
  } else {
    await group.addMembers([walletAddress]);
    await conversation.send(
      `User added to the group\n- Group ID: ${groupId}\n- Wallet Address: ${walletAddress}`,
    );
  }
}

Verify NFT ownership

The bot checks if a wallet owns the required NFT using Alchemy's API:

async function checkNft(
  walletAddress: string,
  collectionSlug: string,
): Promise<boolean> {
  const alchemy = new Alchemy(settings);
  try {
    const nfts = await alchemy.nft.getNftsForOwner(walletAddress);

    const ownsNft = nfts.ownedNfts.some(
      (nft) =>
        nft.contract.name?.toLowerCase() === collectionSlug.toLowerCase(),
    );
    console.log("is the nft owned: ", ownsNft);
    return ownsNft;
  } catch (error) {
    console.error("Error fetching NFTs from Alchemy:", error);
  }
  return false;
}

Usage

1. Start the bot with your environment variables configured
2. Message the bot at its address to create a new group using /create
3. Once you have the group ID, you can add members using /add <group_id> <wallet_address>
4. The bot will verify NFT ownership and add the wallet if they own the required NFT

Run the agent

# git clone repo
git clone https://github.com/ephemeraHQ/xmtp-agent-examples.git
# go to the folder
cd xmtp-agent-examples
# install packages
yarn
# generate random keys (optional)
yarn gen:keys
# run the example
yarn examples:gated