MiniKit Overview

Easiest way to build Mini Apps on Base

MiniKit is easiest way to build Mini Apps on Base, allowing developers to easily build applications without needing to know the details of the SDK implementation. It integrates seamlessly with OnchainKit components and provides Coinbase Wallet-specific hooks.

Why MiniKit?

MiniKit streamlines mini-app development by providing a comprehensive toolkit that makes complex Farcaster SDK interactions intuitive:

Simplified Development

Build apps with minimal knowledge of the Farcaster SDK

Coinbase Wallet Integration

Access Coinbase Wallet-specific hooks

Component Compatibility

Use OnchainKit components out of the box with MiniKit

Automatic Setup

CLI tool for quick project scaffolding with webhooks and notifications

Use Cases

Gaming mini apps

Social mini apps

Payment mini apps

And many more possibilities!

Quick Start

The fastest way to get started with MiniKit is to use the CLI to bootstrap a new project:

npx create-onchain --mini

Quick Start Guide

You can also follow our comprehensive Quick Start guide for detailed setup instructions

This command will:

1. Project Setup

   Set up a new project with both frontend and backend components

2. Webhook Configuration

   Configure webhooks and notifications
3. Account Association

   Set up account association generation
4. Demo App Creation

   Create a demo app showcasing onchain abilities using OnchainKit

After running the command, follow the prompts to configure your project.

We recommend using Vercel to deploy your MiniKit app, as it integrates seamlessly with the upstash/redis backend required for webhooks, and notifications. The CLI will guide you through setting up the necessary environment variables for your Redis database.

Provider

The MiniKitProvider wraps your application and provides global access to the SDK’s context. It handles initialization, events, and automatically applies client safeAreaInsets to ensure your app doesn’t overlap parent application elements.

import { MiniKitProvider } from '@coinbase/onchainkit/minikit';

function App({ children }) {
  return (
    <MiniKitProvider
      projectId='your-project-id'
      notificationProxyUrl='/api/notification'
    >
      {children}
    </MiniKitProvider>
  );
}

Props

The MiniKitProvider accepts the following props:

children · React.ReactNode · required

React components to be wrapped by the provider

notificationProxyUrl · string · default: "/api/notification"

Optional URL to override the default /api/notification proxy

...OnchainKitProviderProps · object

All props from OnchainKitProvider are also supported

The provider sets up wagmi and react-query providers automatically. It configures connectors to use the Farcaster connector if sdk.context is set, with a fallback to CoinbaseWallet. This allows the same application to run both as a Mini App and as a standalone application.

Hooks

MiniKit provides several utility hooks that wrap the SDK functionality, making it easy to access different features.

useMiniKit

This hook handles initialization of the application and provides access to the SDK context.

const {
  setFrameReady,
  isFrameReady,
  context,
  updateClientContext,
  notificationProxyUrl,
} = useMiniKit();

// Call setFrameReady() when your app is ready to be shown
useEffect(() => {
  if (!isFrameReady) {
    setFrameReady();
  }
}, [isFrameReady, setFrameReady]);

Returns:

ready · () => Promise<MiniKitContextType>

Removes splash screen and shows the application

isReady · boolean

Whether the app is ready to be shown

context · FrameContext | null

The current frame context

updateClientContext · (params: UpdateClientContextParams) => void

Update client context

notificationProxyUrl · string

The notification proxy URL

useAddFrame

This hook adds a Mini App to the user’s list of Mini Apps and returns notification details.

const addFrame = useAddFrame();

// Usage
const handleAddFrame = async () => {
  const result = await addFrame();
  if (result) {
    console.log('Frame added:', result.url, result.token);
  }
};

Returns:

addFrame · () => Promise<{ url: string; token: string; } | null>

Function that adds frame and returns notification details

useNotification

This hook allows sending notifications to users who have added your frame. It requires a token and URL, which are returned when a user adds your frame.

const sendNotification = useNotification();

// Usage
const handleSendNotification = () => {
  sendNotification({
    title: 'New High Score!',
    body: 'Congratulations on your new high score!',
  });
};

Notifications require a backend proxy to avoid CORS restrictions. The CLI automatically sets up this proxy at /api/notification, but you can override this in the MiniKitProvider.

useOpenUrl

This hook wraps sdk.actions.openUrl and falls back to window.open when outside a frame context.

const openUrl = useOpenUrl();

// Usage
<button onClick={() => openUrl('https://example.com')}>Visit Website</button>;

useClose

This hook wraps the sdk.actions.close functionality.

const close = useClose();

// Usage
<button onClick={close}>Close</button>;

useComposeCast

The useComposeCast hook provides functionality to open the Farcaster compose interface with pre-filled content.

import { useComposeCast } from '@coinbase/onchainkit/minikit';

export default function ComposeCastButton() {
  const { composeCast } = useComposeCast();

  const handleCompose = () => {
    composeCast({
      text: 'Just minted an awesome NFT using @coinbase OnchainKit! 🚀',
    });
  };

  const handleComposeWithEmbed = () => {
    composeCast({
      text: 'Check out this amazing frame!',
      embeds: ['https://your-frame-url.com'],
    });
  };

  return (
    <div>
      <button onClick={handleCompose}>Share Achievement</button>
      <button onClick={handleComposeWithEmbed}>Share Frame</button>
    </div>
  );
}

Parameters:

• text: string - The text content for the cast
• embeds?: string[] - Optional array of URLs to embed in the cast

Returns:

• composeCast: (params: ComposeCastParams) => void - Function to open compose interface

useViewCast

The useViewCast hook provides functionality to view a specific Farcaster cast by its hash.

import { useViewCast } from '@coinbase/onchainkit/minikit';

export default function ViewCastButton() {
  const { viewCast } = useViewCast();

  const handleViewCast = () => {
    viewCast({
      hash: '0x32aed77ca61c92d253b98983f1e0fd20a8bd5745',
    });
  };

  const handleViewAnotherCast = () => {
    viewCast({
      hash: '0x48f4d2c45e7b1a923d5c6f8e9a7b2c1d5e8f3a6b',
    });
  };

  return (
    <div>
      <button onClick={handleViewCast}>View Featured Cast</button>
      <button onClick={handleViewAnotherCast}>View Community Cast</button>
    </div>
  );
}

Parameters:

• hash: string - The hash of the cast to view

Returns:

• viewCast: (params: ViewCastParams) => void - Function to view a specific cast

usePrimaryButton

This hook accepts primary button options and a callback which will be called on click.

usePrimaryButton({ text: 'Submit Score' }, () => {
  // Handle button click
  submitScore();
});

useViewProfile

This hook wraps sdk.actions.viewProfile, accepting an FID but falling back to the client’s FID.

const viewMyProfile = useViewProfile(); // Uses client's FID
const viewUserProfile = useViewProfile(123456); // Uses specified FID

// Usage
<button onClick={viewMyProfile}>View My Profile</button>
<button onClick={viewUserProfile}>View User Profile</button>

useAuthenticate

This hook allows users to sign in with Farcaster. It wraps the SDK’s signIn message, adding a default nonce and verification.

const { signIn } = useAuthenticate();

// Usage
const handleSignIn = async () => {
  const result = await signIn({
    domain: 'your-domain.com',
    siweUri: 'https://your-domain.com/login',
  });

  if (result) {
    // Handle successful authentication
    console.log('Authenticated:', result);
  }
};

Authentication requires additional setup utilizing an auth framework like next/auth or manually integrating session storage and route/component authentication.

CLI

The MiniKit CLI is the easiest way to get started. It automatically creates a sample application that integrates different parts of the SDK and some OnchainKit components.

npx create-onchain --mini

Features

The CLI creates an application with:

Frontend and Backend Integration

Complete setup for adding Mini Apps, webhooks, and notifications using upstash/redis for data storage (compatible with Vercel). Requires users to sign up for an upstash/redis account and add their key and URL to the .env file.

The CLI creates both frontend and backend components to support adding Mini Apps, webhooks, and notifications. While a frontend-only option was considered, the ability to add Mini Apps and handle notifications requires backend support. If you don’t need these features, you can easily remove the database and related routes after project creation.

Account Association Generation

Automatically generates valid account associations and configures the necessary environment variables.

.well-known/farcaster.json Configuration

Sets up the required configuration file:

{
  "accountAssociation": {
    "header": "eyJmaWQiOjgxODAyNiwidHlwZSI6ImN1c3RvZHkiLCJrZXkiOiIweDU4YjU1MTNjMzk5OTYzMjU0MjMzMmU0ZTJlRDAyOThFQzFmRjE4MzEifQ",
    "payload": "eyJkb21haW4iOiI4MGI2LTI2MDAtMWYxOC0yNGM5LTYxMDUtNS0wLTQtNzA2Lm5ncm9rLWZyZWUuYXBwIn0",
    "signature": "MHhmOGQ1YzQyMmU3ZTZlMWNhMzU1ZmNmN2ZjYzFmYjMyZWRhZmEyNWU1NjJiMzlhYzE4OWNlMmM5ODU3Y2JjZWViNzlkZTk2ZjhiNTc5NzZjMDM2NzM4Y2UwYjhhOGQxZmMyZDFhYzA2NTdiZTU5N2VhZjFhZDE1ODBmMGQyYjJhODFi"
  },
  "frame": {
    "version": "next",
    "name": "MiniKit",
    "iconUrl": "https://onchainkit.xyz/favicon/48x48.png?v4-19-24",
    "splashImageUrl": "https://onchainkit.xyz/favicon/48x48.png?v4-19-24",
    "splashBackgroundColor": "#000000",
    "homeUrl": "https://your-domain.app/minikit"
  }
}

Notification Proxy

Automatically sets up a proxy route at /api/notification used by the useNotification hook when sending notifications.

Webhooks

Implements webhooks using the Farcaster key registry contract for verification. Allows applications to respond to events such as FRAME_ADDED.

Demo Application

The CLI also creates a demo snake game application that showcases:

• Buttons to add the frame and connect your wallet
• High score tracking with attestations using OnchainKit’s <Transaction/> component
• Score display using OnchainKit’s <Identity/> components to resolve ENS names
• Notifications for high scores (rate limited to one every 30 seconds)

Next Steps

Now that you have MiniKit set up, you can:

1. Explore the Demo

   Explore the demo application to understand how the hooks work

2. Customize Your App

   Customize the application to fit your needs

3. Deploy

   Deploy your application to a hosting provider like Vercel

Enjoy building!