Privy Integration for Authentication in Crypto Mobile Applications
Privy is an embedded wallet provider with emphasis on UX. Unlike MetaMask or WalletConnect, Privy creates a wallet transparently for the user: email login or social authorization, and the wallet is ready. No "install extension" or "save seed phrase" steps. For crypto apps targeting mass audiences, this significantly lowers the barrier to entry.
Privy Architecture
The wallet private key is encrypted and stored in Privy infrastructure with client-side encryption—Privy has no access to the plain-text key. During authentication, the key is decrypted on the user's device using data from the OAuth provider and Privy's hardware token.
The scheme is closer to custodial than Web3Auth with MPC, but substantially simpler to implement and provides smoother UX.
Integration in React Native
Privy provides official @privy-io/expo SDK for Expo and @privy-io/react-native for bare React Native.
// App.tsx
import { PrivyProvider } from "@privy-io/expo";
export default function App() {
return (
<PrivyProvider
appId="your-privy-app-id"
config={{
loginMethods: ["email", "google", "apple"],
embeddedWallets: {
createOnLogin: "users-without-wallets",
},
}}
>
<Navigation />
</PrivyProvider>
);
}
// LoginScreen.tsx
import { useLoginWithOAuth, usePrivy } from "@privy-io/expo";
const { user, logout } = usePrivy();
const { login: loginWithGoogle } = useLoginWithOAuth({ provider: "google" });
// After login:
const wallet = user?.linkedAccounts.find(
(acc) => acc.type === "wallet" && acc.walletClientType === "privy"
);
// wallet.address — wallet address
The embedded wallet is created automatically on first login (if createOnLogin: "users-without-wallets"). Subsequent login restores the same address.
Transaction Signing
Privy provides useEmbeddedWallet for signing via built-in UI (user confirms transaction in Privy modal) or direct provider access:
const { wallets } = useEmbeddedWallet();
const embeddedWallet = wallets.find((w) => w.walletClientType === "privy");
await embeddedWallet.switchChain(8453); // Base
const provider = await embeddedWallet.getEthereumProvider();
const ethersProvider = new ethers.BrowserProvider(provider);
const signer = await ethersProvider.getSigner();
const tx = await signer.sendTransaction({
to: recipientAddress,
value: ethers.parseEther("0.01"),
});
Important note: Privy SDK works through WebView under the hood on mobile platforms. This means additional cold start overhead and potential lifecycle issues on Android (Activity recreation on screen rotation). You need to test scenarios: background mode → foreground during active Privy session.
Dashboard Configuration
In Privy Dashboard: App Settings → Login Methods — enable required providers. For Google: OAuth Client ID from Google Cloud Console. For Apple: Service ID, private key, key ID.
Allowed origins for production — your app domain. For mobile — bundle ID (iOS) and package name (Android) in the Mobile Apps section.
Privy Auth integration in React Native / Expo application — 1–2 weeks. Cost estimated individually after analyzing requirements for supported networks and authentication methods.