> ## Documentation Index
> Fetch the complete documentation index at: https://litprotocol-feat-rusk-sdk.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Stytch WhatsApp OTP

> Enter your phone number to receive a one-time password (OTP) via WhatsApp. The OTP will be sent through Stytch's WhatsApp service via your backend to your WhatsApp account.

# Prerequisites

<Warning>
  Backend Required: This authentication method requires a backend service
  that handles Stytch Email OTP operations. The auth service already has the
  implementation in place with the `/stytch/email/send-otp` and
  `/stytch/email/verify-otp` endpoints, but they are disabled by default. Simply
  run your auth service at the configured URL to enable Stytch Email OTP
  functionality.
</Warning>

<Note>
  Lit Auth Server URLs. Please refer to [Auth
  Services](/sdk/getting-started/auth-services#naga-dev-network) section.
</Note>

<Steps>
  <Step title="Send OTP to WhatsApp">
    Enter your phone number to receive a one-time password (OTP) via WhatsApp. The OTP will be sent through Stytch's WhatsApp service via your backend to your WhatsApp account.

    ```ts theme={null}
    import { StytchWhatsAppOtpAuthenticator } from "@lit-protocol/auth";

    const { methodId } = await StytchWhatsAppOtpAuthenticator.sendOtp({
      phoneNumber: "+1234567890",
      authServiceBaseUrl: "https://naga-auth-service.onrender.com",
    });
    ```
  </Step>

  <Step title="Verify OTP">
    Enter the OTP code sent to your WhatsApp to verify your identity and generate authentication data.

    ```ts theme={null}
    import { StytchWhatsAppOtpAuthenticator } from "@lit-protocol/auth";

    const authData = await StytchWhatsAppOtpAuthenticator.authenticate({
      methodId: methodId, // from sendOtp step
      code: "123456", // user-entered OTP code
      authServiceBaseUrl: "https://naga-auth-service.onrender.com"
    });
    ```
  </Step>

  <Step title="Setup TOTP 2FA (Optional)">
    Add an extra layer of security to your account by setting up TOTP (Time-based One-Time Password) 2FA. This will allow you to use authenticator apps like Google Authenticator, Authy, or 1Password for future logins.

    See [TOTP 2FA](/sdk/auth/pkp-native-auth/pkp-stytch-2fa-totp-auth) for more details.
  </Step>

  <Step title="Get or Mint a PKP">
    You can select an existing PKP associated with your account or mint a new one.

    <CodeGroup>
      ```ts Mint a fresh PKP theme={null}
      const res = await litClient.authService.mintWithAuth({
        authData: authData,
      });
      ```

      ```ts Using an existing PKP theme={null}
      const result = await litClient.viewPKPsByAuthData({
        authData: {
          authMethodType: authData.authMethodType,
          authMethodId: authData.authMethodId,
        },
        pagination: {
          limit: 5,
          offset: 0,
        }
      });
      ```
    </CodeGroup>
  </Step>

  <Step title="Generate Auth Context">
    Use your PKP's public key to create an AuthContext. This method will cache two things:

    1. session key pair - a temporary cryptographic key pair generated on the client side that acts as a temporary identity for the client application. It consists of:
       * A public key - shared with the Lit nodes
       * A secret key (private key) - kept securely on the client
    2. Delegation AuthSig aka. the inner auth sig - a cryptographic attestation from the Lit Protocol nodes that authorises your session key to act on behalf of your PKP.

    ```ts theme={null}
    const authContext = await authManager.createPkpAuthContext({
      authData: authData, // <-- Retrieved earlier
      pkpPublicKey: pkpInfo.pubkey,
      authConfig: {
        resources: [
          ["pkp-signing", "*"],
          ["lit-action-execution", "*"],
        ],
        expiration: new Date(Date.now() + 1000 * 60 * 60 * 24).toISOString(),
        statement: "",
        domain: window.location.origin,
      },
      litClient: litClient,
    });
    ```
  </Step>
</Steps>