> ## Documentation Index
> Fetch the complete documentation index at: https://tfh-docs-audit-mcp-content-fixes.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Selfie Check

> A medium-assurance biometric credential using the device camera for liveness and facial similarity.

| Property        | Value                                                                                                       |
| --------------- | ----------------------------------------------------------------------------------------------------------- |
| Issued by       | [Tools for Humanity](https://www.toolsforhumanity.com) (verified issuer)                                    |
| ID              | `11`                                                                                                        |
| Validity period | 90 days (the default duration of the credential; generally the maximum recommended sybil resistance window) |

## Introduction

Selfie Check uses the user's mobile device camera for liveness and facial
similarity checks. It adds friction against automated and repeated account
creation without requiring a Proof of Human. Unlike high-assurance Orb verification,
Selfie Check does not provide a strict one-person-one-account guarantee and is
considered a medium-assurance verification method.

Use Selfie Check for:

* **Liveness detection:** Confirm the user is a real person, not a spoof or injection attack.
* **Abuse resistance:** Add friction to automated and repeated account creation.
* **Continuity:** Confirm a returning user is the same person who originally enrolled.

Selfie Check has a 90-day inactivity window. After 90 days without use, the
user completes the camera flow again before returning another proof.

Anyone with World ID App can use Selfie Check. No Orb, passport or
other prerequisite credential is required.

## Understand the Sybil score

Each Selfie Check response includes a versioned `sybil_score` that
can help an app assess the risk of repeated enrollment. It is a risk signal, not
a uniqueness verdict, and should be considered alongside other evidence. The
response also includes an `integrity_bundle` that lets the Developer Portal
verify it came from an authentic World ID App.

## Choose your integration

Use **session proofs** if users need to complete Selfie Check more than once—for
example, when returning to your app or confirming a sensitive action. Create a
session on their first successful verification, then prove that same session on
subsequent checks.

Use a **uniqueness request** when your app needs to allow each user to complete a
particular action once, such as claiming a reward. The one-time nullifier for that
action cannot serve as a reusable verification flow. Selfie Check remains a
medium-assurance signal; neither flow provides a strict one-person-one-account
guarantee.

* [Integrate with sessions](/world-id/idkit/session-proofs) — recommended for returning-user checks.
* [Integrate a one-time check](/world-id/idkit/integrate) — use a uniqueness request.

## How it works

Use IDKit to integrate Selfie Check into your application.

* **On mobile (iOS/Android):** Use IDKit to generate a deep link and attach it to a "Verify" CTA. When the user taps it, they are redirected to World ID App to complete Selfie Check.
* **On desktop:** Use IDKit to generate a QR code and display it to the user. When the user scans it with their mobile device camera, World ID App launches and guides them through Selfie Check.

## User Experience Flow

1. **Challenge:** The user initiates the flow on your app (Relying Party).
2. **Hand-off:** The user is redirected to World ID App. If they don't have World ID App installed, they are guided to download it and go straight into the Selfie Check experience.
3. **Enrollment/Auth:**
   * **New User:** Enrolls with a selfie and liveness check.
   * **Returning User:** Completes a short camera check to verify continuity.
4. **Success:** The user returns to your application with a verified credential.

## Next steps

See [Integrate IDKit](/world-id/idkit/integrate) for the complete integration flow.

Testing your integration? See [Testing Selfie Check in Sandbox](/world-id/sandbox/testing-selfie-check)
for coverage, critical user journeys, and known limitations.