> ## Documentation Index
> Fetch the complete documentation index at: https://docs.0xkey.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Authenticate a user with email

Email OTP authentication runs through the [Auth Proxy](/reference/auth-proxy). Use React Wallet Kit or `@0xkey-io/core` on the client and [`@0xkey-io/sdk-server`](/sdks/javascript-server) server actions on the backend.

<CardGroup cols={2}>
  <Card title="Email authentication" icon="envelope" href="/authentication/email">
    OTP flow, Auth Proxy endpoints, and security model
  </Card>

  <Card title="React Wallet Kit" icon="react" href="/sdks/react/getting-started">
    Built-in email OTP in the login modal
  </Card>

  <Card title="TypeScript server" icon="server" href="/sdks/javascript-server">
    `server.sendOtp`, `server.verifyOtp`, `server.otpLogin`
  </Card>

  <Card title="GitHub — otp-auth" icon="github" href="https://github.com/0xkey-io/sdk-js/tree/main/examples/otp-auth">
    End-to-end OTP example
  </Card>
</CardGroup>