> For the complete documentation index, see [llms.txt](https://docs.vida.id/identity-stack/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vida.id/identity-stack/authentication/authentication-factors/biometric-device-selfie-id/integration-methods/selfie-id-api.md).

# Selfie ID API

VIDA’s Selfie ID authentication APIs enable users to register and authenticate using the built-in biometric capabilities of their mobile devices. This allows for fast, seamless, and secure authentication without relying on passwords or OTPs.

**How it works**

* **Provisioning/Registration:**\
  When a user sets up Selfie ID for the first time, VIDA issues a challenge prompting the app to capture the user’s selfie through the device's camera. VIDA validates the biometric and, upon success, issues a **Credential ID** that is stored on the partner backend for future use.
* **Authentication:**\
  For future logins or sensitive actions, the app reuses the stored Credential ID to trigger a face capture challenge. VIDA verifies the user's selfie against the registered credential using advanced face-matching and liveness detection. A signed response is sent back with the result, ensuring strong identity validation.

Selfie ID is especially useful for high-value transactions, sensitive operations, or anytime secure step-up authentication is needed.