Coinbase Wallet & Extension: Integration Patterns and Security Best Practices
Coinbase Wallet (the non-custodial wallet application) and its browser extension provide a convenient way for users to manage keys and interact with decentralized applications. Integrating Coinbase Wallet support into a dApp can improve conversion by offering a trusted connection method that many users recognise. There are two common integration paths: detecting an injected provider (the Coinbase Wallet extension or other injected wallets that expose `window.ethereum`) and using WalletLink / Coinbase Wallet SDK for mobile and deep-link flows. This guide explains practical patterns, permission handling, signing hygiene, and user education practices that help keep your integration safe and user-friendly.
Detection is straightforward: look for `window.ethereum` and optionally examine the provider metadata to infer that it's a Coinbase Wallet instance. If the extension is present, call `ethereum.request({ method: 'eth_requestAccounts' })` in response to a user action to obtain accounts. Avoid automatic permission prompts on page load; only request access when the user intentionally clicks "Connect". If the extension is not available, present the user with a WalletLink QR code or a mobile deep-link to the Coinbase Wallet app. WalletLink provides a robust path for mobile users to connect securely via an encrypted session initiated by scanning a QR code or following a deep link that opens the wallet app.
Permission UX matters: explain why your dApp needs access to an account and what actions require signing. Provide readable descriptions and contextual modals before initiating `eth_requestAccounts` or a transaction signature. For transactions, present human-readable details including recipient address, token symbol and amount, gas estimate, and any contract method information you can decode. Consider using ABI decoding libraries to present clear contract method names and parameters to the user. This reduces the risk of a user approving an unintended transfer or interacting with a malicious contract due to unclear prompts.
For signing operations, always ensure the dApp verifies transaction parameters both client-side and server-side. Do not rely solely on client-side checks: implement server-side validation and confirmations for high-value operations. Use nonces and short-lived session tokens for authentication workflows that rely on signed messages (e.g., login via `personal_sign`). Educate users about the difference between signing a transaction (which can move funds) and signing messages (which is often used for authentication). Avoid requesting signatures for arbitrary messages without clear, time-bound intent.
WalletLink sessions should be handled securely: generate a unique session, present the QR or deep link, and wait for the wallet to establish the connection. Cleanly handle failed sessions and timeouts, and provide helpful troubleshooting steps (install the app, check network connectivity, try a different browser). When supporting multiple wallet types, normalize the provider API via libraries like web3modal or onboard.js to simplify code paths and minimize provider-specific bugs.
Mobile considerations are critical: deep-linking and WalletLink behave differently on iOS and Android. Test across real devices and browsers; some mobile browsers restrict window opening behaviors that impact deep links. Provide explicit instructions for users to install Coinbase Wallet, enable the extension, and how to approve signatures. For accessibility, include keyboard and screen-reader friendly labels and avoid showing QR codes without alt text or textual fallback instructions.
Finally, user education and phishing resistance are essential. Warn users about phishing sites that replicate wallet UI or impersonate dApps, and recommend hardware wallets for high-value accounts. Provide a clear FAQ on what the wallet will and will not ask (never ask for seed phrases), and include links to official support resources. By combining clear permission flows, robust WalletLink fallback paths, server-side validation, and thorough mobile testing, Coinbase Wallet integration can significantly improve user trust and conversion while keeping security risks low.