We’re so excited that mini apps are coming to Coinbase Wallet! The purpose of this guide is to go over how to build or update your mini app so it works as well as possible in Coinbase Wallet.

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Using MiniKit

Quick Start with MiniKit

If you use MiniKit and/or follow the MiniKit quickstart guide, your mini app will work out of the box in Coinbase Wallet!

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

Debugging Guide

If you’re already using MiniKit and experiencing issues, you can refer to our debugging guide

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Authentication

As a general rule of thumb for building any mini app, we recommend that you do not automatically request that the user logs in/signs a message and instead that authentication is only used when it’s needed (e.g. signing up for an event, viewing authenticated resources, etc).

Below we will quickly cover the different methods of authentication offered for mini apps and how well each of them work in Coinbase Wallet:

The official mini apps SDK offers a set of actions (which MiniKit offers as well) so that users of your mini app can be led to do things back in clients like Coinbase Wallet (e.g. compose a cast, view a profile, etc).

Always use official SDK functions instead of Warpcast-specific deeplinks in your mini app.

While some developers have used Warpcast-specific deeplinks in the openUrl function as a workaround, this approach can create problems. Warpcast-specific deeplinks might not match Coinbase Wallet-specific deeplinks, potentially leaving users dead-ended and unable to take further action in your mini app.

Using the official SDK functions ensures your users have the best viewing experience possible across all supported clients, including Coinbase Wallet.

Note: For developers who include a “Share” button in their miniapp, we recommend that you move over to the new composeCast function in the miniapps SDK instead of using a Warpcast-specific deeplink.

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Wallet Interactions

Wallet interactions are a core part of the miniapp experience. We want to ensure both that building wallet interactions on top of the Coinbase Wallet is smooth for developers and that users can choose/have funds sent to their Coinbase Wallet when interacting with mini apps.

As a mini app host, we expose an EIP-1193 Ethereum Provider that can be accessed in two primary ways:

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Metadata

Farcaster has recently extended the metadata spec for mini apps, which allows developers to add screenshot links, categories, and more to their manifest (farcaster.json) file. Making use of these new metadata fields is highly recommended for increasing the chance that your mini app could be featured throughout Coinbase Wallet.

Below is a table of the new metadata fields introduced, what they mean/could potentially be used for, and an example of what a manifest file could look like with these new fields (all taken from the official spec)

Note: Only ~30 of the hundreds of mini apps we’ve seen have set this data, we highly recommend that you set this metadata as it will give your mini app a better shot at being featured.

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Example Manifest

{
  "accountAssociation": {
    "header": "eyJmaWQiOjkxNTIsInR5cGUiOiJjdXN0b2R5Iiwia2V5IjoiMHgwMmVmNzkwRGQ3OTkzQTM1ZkQ4NDdDMDUzRURkQUU5NDBEMDU1NTk2In0",
    "payload": "eyJkb21haW4iOiJyZXdhcmRzLndhcnBjYXN0LmNvbSJ9",
    "signature": "MHgxMGQwZGU4ZGYwZDUwZTdmMGIxN2YxMTU2NDI1MjRmZTY0MTUyZGU4ZGU1MWU0MThiYjU4ZjVmZmQxYjRjNDBiNGVlZTRhNDcwNmVmNjhlMzQ0ZGQ5MDBkYmQyMmNlMmVlZGY5ZGQ0N2JlNWRmNzMwYzUxNjE4OWVjZDJjY2Y0MDFj"
  },
  "frame": {
    "version": "1",
    "name": "Example Mini App",
    "iconUrl": "https://example.com/app.png",
    "splashImageUrl": "https://example.com/logo.png",
    "splashBackgroundColor": "#000000",
    "homeUrl": "https://example.com",
    "webhookUrl": "https://example.com/api/webhook",
    "subtitle": "Example Mini App subtitle",
    "description": "Example Mini App subtitle",
    "screenshotUrls": [
      "https://example.com/screenshot1.png",
      "https://example.com/screenshot2.png",
      "https://example.com/screenshot3.png"
    ],
    "primaryCategory": "social",
    "tags": [
      "example",
      "mini app",
      "coinbase wallet"
    ],
    "heroImageUrl": "https://example.com/og.png",
    "tagline": "Example Mini App tagline",
    "ogTitle": "Example Mini App",
    "ogDescription": "Example Mini App description",
    "ogImageUrl": "https://example.com/og.png"
  }
}

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Notifications

You will soon be able to send notifications from your Mini App that will appear in Coinbase Wallet. These notifications help re-engage users when something important happens, like a new drop, an update, or a reminder to complete an action. There are two ways to integrate: