FarHack

Welcome to the ultimate Farcaster hackathon to learn how to build innovative Frames and Bots with XMTP. Happy coding 🫡

Prizes 🏆

🤖 Best use of an XMTP Bot with Farcaster - $500

This prize goes to the team that most effectively creates a Bot that uses Farcaster in a meaningful way.

Requirements:

Develop a Farcaster Bot using XMTP libraries

To create a new XMTP bot using BotKit cli tool:

npx create-xmtp-bot <bot-name>
cd <bot-name>

This is a code example of a bot that replies gm :

import { run, HandlerContext } from "@xmtp/botkit";

run(async (context: HandlerContext) => {
  // Get the message and the address from the sender
  const { content, senderAddress } = context.message;

  // Read or write to Farcaster

  // To reply, just call `reply` on the HandlerContext.
  await context.reply("gm");
});

Resources

• BotKit: Tooling for creating bots with XMTP.
• Tutorial: Learn how to build and deploy a bot.
• Conversational: Drive retention with conversations and subscriptions.
• GPT: Relay messages through Open AI APIs.

🖼️ Best Chat Frame - $500

This prize goes to the best Frame compatible with messaging apps.

Requirements:

Integrate your Frame with XMTP

Metadata

In compliance with Open Frames, Use a meta tag in your frame's HTML to declare the client protocols your frame supports.

<meta property="of:accepts:xmtp" content="vNext" />

Validate incoming messages

Implement message validation using @xmtp/frames-validator to ensure the authenticity of incoming POST requests.

import { validateFramesPost } from "@xmtp/frames-validator";

export function handler(requestBody: any) {
  if (requestBody.clientProtocol.startsWith("xmtp")) {
    const { verifiedWalletAddress } = await validateFramesPost(requestBody);
    // Handle verified XMTP payload
  } else {
    // Handle Farcaster or other protocol payloads
  }
}

Frameworks

Popular frameworks have already integrated Open Frames into their stack:

OnChainKit

Discover how OnchainKit seamlessly incorporates XMTP payloads

Metadata:

const frameMetadata = getFrameMetadata({
  /**
   * Frame metadata like Image, Buttons, Input, etc.
   */
  isOpenFrame: true,
  accepts: { xmtp: "vNext" },
});

export const metadata: Metadata = {
  /**
   * ...other metadata
   */
  other: {
    ...frameMetadata,
  },
};

Validate incoming messages

import {
  isXmtpFrameRequest,
  getXmtpFrameMessage,
} from "@coinbase/onchainkit/xmtp";
/* ... */
async function getResponse(req: any): Promise<NextResponse> {
  const body: FrameRequest = await req.json();
  if (isXmtpFrameRequest(body)) {
    const { isValid, message } = await getXmtpFrameMessage(body);
    // ... do something with the message if isValid is true
    if (isValid) {
      const { verifiedWalletAddress } = message;
      // ... do something with the verifiedWalletAddress
    }
  } else {
    // ...
  }
}

• OnChainKit: Official OnchainKit documentation.
• Quickstart: Onchainkit quickstart that integrates XMTP.

Frames.js

Learn more about the integration of XMTP payloads within FrameJS

Metadata

const acceptedProtocols: ClientProtocolId[] = [
  {
    id: "xmtp",
    version: "vNext",
  },
  {
    id: "farcaster",
    version: "vNext",
  },
];

Validate incoming messages:

import { getXmtpFrameMessage, isXmtpFrameActionPayload } from "frames.js/xmtp";

let fid: number | undefined;
let walletAddress: string | undefined;

if (isXmtpFrameActionPayload(previousFrame.postBody)) {
  const frameMessage = await getXmtpFrameMessage(previousFrame.postBody);
  const { verifiedWalletAddress } = frameMessage;
  // Do something with xmtp wallet address
} else {
  // Do something else
}

• Frames.js: Official Framesjs Documentation.
• Quickstart: Frames.js example that integrates XMTP.

Frog

Metadata

To build a Frame with XMTP, you must first add XMTP metadata.

const addMetaTags = (client: string, version?: string) => {
  // Follow the OpenFrames meta tags spec
  return {
    unstable_metaTags: [
      { property: `of:accepts`, content: version || "vNext" },
      { property: `of:accepts:${client}`, content: version || "vNext" },
    ],
  };
};

export const app = new Frog(addMetaTags("xmtp"));

Validate incoming messages:

Install the @xmtp/frames-validator package to validate incoming messages.

npm install @xmtp/frames-validator

Add the middleware to validate incoming messages.

import { validateFramesPost } from "@xmtp/frames-validator";

const xmtpSupport = async (c: Context, next: Next) => {
  // Check if the request is a POST and relevant for XMTP processing
  if (c.req.method === "POST") {
    const requestBody = (await c.req.json().catch(() => {})) || {};
    if (requestBody?.clientProtocol?.includes("xmtp")) {
      c.set("client", "xmtp");
      const { verifiedWalletAddress } = await validateFramesPost(requestBody);
      c.set("verifiedWalletAddress", verifiedWalletAddress);
    } else {
      // Add farcaster check
      c.set("client", "farcaster");
    }
  }
  await next();
};

app.use(xmtpSupport);

Access verified wallet address:

app.frame("/", (c) => {
  /* Get Frame variables */
  const { buttonValue, inputText, status } = c;

  // XMTP verified address
  const { verifiedWalletAddress } = c?.var || {};

  /* return */
});

• Frog: XMTP Frog official middleware
• Quickstart: Frog open frame XMTP quickstart

• Send your Frame through Converse to hi.xmtp.eth.

🔔 Best Use of XMTP to Send Notifications - $500

Implement a Frame or Bot that sends notifications through XMTP.

Requirements:

Send notifications using XMTP libraries

Install the js sdk:

yarn add @xmtp/xmtp-js ethers

Send notification:

import { Wallet } from "ethers";
import { Client } from "@xmtp/xmtp-js";

// Function to send a broadcast message to a list of recipients
async function sendNotification(recipient, message) {
  // In a real application, use your wallet
  const signer = new Wallet("private key");
  const xmtp = await Client.create(signer);

  // Check if the recipient is activated on the XMTP network
  if (await xmtp.canMessage(recipient)) {
    const conversation = await xmtp.conversations.newConversation(recipient);
    await conversation.send(message);
    console.log(`Message successfully sent to ${recipient}`);
  } else {
    console.log(`Recipient ${recipient} is not activated on the XMTP network.`);
  }
}
// Example usage
sendNotification("Hello from Farcaster!", "0x123...");

---

Messaging apps 💬

Test the bots in messaging apps

• Converse: Own your conversations. Works with Frames (Frame Transactions TBA).
• Coinbase Wallet: Your key to the world of crypto. (Frame support TBA).
• dev-inbox: Web messaging client (Frame Transactions TBA).

Identities 🥷🏻

Learn about the 2 million identities part of XMTP by visiting the Dune dashboard.

Examples 🔥

See live examples in the Awesome XMTP ⭐️ repo.