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

# Passkey Login: Identifier-First

> Identifier-first flow where users enter their username/email and the system uses Passkey Intelligence to automatically determine the optimal authentication method.

## Identifier-First Login

This is an **identifier-first flow** where users enter their identifier (email, phone, or username) into the login textfield first. The system then uses **[Passkey Intelligence](/corbado-connect/features/passkey-intelligence)** to automatically determine if passkey login should be triggered on the current device or via cross-device authentication.

**Critical for Login Success:** Passkey Intelligence only triggers platform or cross-device login when there's a high probability of success. This smart decision-making significantly increases overall login completion rates by avoiding failed authentication attempts.

<Info>
  **How Passkey Intelligence Works:** After the user enters their identifier, the system uses [Passkey Intelligence](/corbado-connect/features/passkey-intelligence) to make smart decisions about authentication. It only triggers platform authentication or cross-device login (via QR code) when there's a high likelihood of success. This prevents users from encountering failed authentication attempts, which significantly improves overall login completion rates.
</Info>

<Tabs>
  <Tab title="macOS" />

  <Tab title="Windows" />

  <Tab title="iOS" />

  <Tab title="Android" />
</Tabs>

<Steps>
  <Step title="User enters identifier">
    * User types their identifier (email, phone, or username) into the login textfield on the web-app.
    * System now knows which user account is attempting to log in.
  </Step>

  <Step title="Passkey Intelligence determines authentication method">
    * The system uses [Passkey Intelligence](/corbado-connect/features/passkey-intelligence) to analyze if this user has a passkey available.
    * It intelligently determines the best authentication approach:
      * **Platform authentication:** If a passkey is stored on the current device
      * **Cross-device authentication:** If a passkey exists on a mobile device (via QR code)
      * **Fallback to traditional login:** If no viable passkey route is detected
    * **Key advantage:** Only triggers passkey login if there's a high probability of success, preventing user frustration from failed attempts.
  </Step>

  <Step title="OS-native biometric modal appears">
    * If Passkey Intelligence determines a passkey is available, the system automatically triggers the authentication prompt.
    * User verifies their identity using their screen lock (e.g., fingerprint, PIN, or face recognition).
  </Step>

  <Step title="Access granted">
    * User is seamlessly logged in and redirected to the dashboard.
  </Step>
</Steps>