Coinbase Wallet injects a Solana provider into the top-level window of web applications. The provider can be used to read on-chain data, establish connections to user accounts, sign messages, and send transactions. You can access this provider at window.coinbaseSolana. 
const getProvider = () => {
  if ("coinbaseSolana" in window) {
    return window.coinbaseSolana;
  }
  // Redirect user if Coinbase Wallet isn’t installed
  window.open("https://www.coinbase.com/wallet", "_blank");
};
If a user does have Coinbase Wallet installed and no provider is found, we recommend redirecting the user to download Coinbase Wallet.