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

# Identity Link API: Integration Guide

> Learn how to integrate VU Identity Link to verify user identities with biometrics and document capture in minutes.

VU Identity Link lets you verify user identities remotely by sending a single-use link that guides the end user through document capture and optional liveness detection. This guide walks you through the complete integration flow from authentication to reading verification results.

## What Identity Link is

One verification is one link. You create it, you share it, and the person opens it in the browser they already have — nothing to install on their side, no SDK to ship on yours. Inside that session they photograph their identity document and, in the `FULL FLOW` type, complete a liveness challenge. VU reads the document with OCR, compares the live face against the photo printed on it, checks both captures for spoofing, and hands you back one consolidated result.

What the person never does is send you a photo of their ID over a messaging app. The captures travel inside the link's own session, and the record they produce lives exactly as long as the two expiration windows configured on your account. After that the API answers `410` for the record and `404` for its images.

<Note>
  **The API is a paid feature.** Only Premium and Pro can obtain a token — on Basic, `POST /oauth/token` answers `401 invalid_client`. Verification quota, expiration windows, branding and location precision all vary by plan. See [Plans](/en/identity-link/plans).
</Note>

## How Identity Link works

<Steps>
  <Step title="Authenticate your backend">
    Obtain a Bearer token using your `clientId` and `clientSecret` via `POST /oauth/token`. The token is valid for 3600 seconds.
  </Step>

  <Step title="Create a verification link">
    Call `POST /links` with the desired flow type (`FULL FLOW` or `ID ONLY`) and optional metadata. You receive a `linkUrl` to share with the user.
  </Step>

  <Step title="Share the linkUrl">
    Deliver the link to your user through email, WhatsApp, SMS, or embed it as a QR code. The link is single-use and expires based on your company configuration.
  </Step>

  <Step title="User completes the flow">
    The user opens the link on their mobile device, captures the front and back of their identity document, and optionally completes a liveness challenge for biometric verification.
  </Step>

  <Step title="Receive a webhook or poll for status">
    VU sends webhook events for every step of the process. Alternatively, poll `GET /verifications/{id}/status` for lightweight status checks.
  </Step>

  <Step title="Read extracted data">
    Once the verification reaches `success`, call `GET /verifications/{id}` to retrieve OCR-extracted fields such as name, document number, birth date, nationality, and geolocation.
  </Step>
</Steps>

## Integration paths

<CardGroup cols={3}>
  <Card title="Authentication" icon="key" href="/en/identity-link/authentication">
    Get your OAuth2 Bearer token and learn where to find your credentials.
  </Card>

  <Card title="Links" icon="link" href="/en/identity-link/links">
    Create, share, and manage single-use verification links.
  </Card>

  <Card title="KYC Results" icon="id-card" href="/en/identity-link/kyc">
    Query verification status and read extracted document data.
  </Card>

  <Card title="Liveness" icon="scan-face" href="/en/identity-link/liveness">
    Understand anti-spoofing biometric checks in the FULL FLOW.
  </Card>

  <Card title="Webhooks" icon="bell" href="/en/identity-link/webhooks">
    Receive real-time server notifications for every verification step.
  </Card>

  <Card title="Errors" icon="triangle-exclamation" href="/en/identity-link/errors">
    Full reference of HTTP status codes and how to resolve them.
  </Card>
</CardGroup>

## Base URL and versioning

All API requests use the following base URL:

```text theme={null}
https://api.identity.vu-one.com/api/v1
```

The current stable version is **v2.3.2**. Breaking changes are announced in the [changelog](/en/identity-link/changelog) with at least 30 days of advance notice.

## Adaptive flow

From version 2.2.0, a `FULL FLOW` link can opt into **adaptive flow** with the `adaptiveFlow` field. When the customer has verified before, the link resolves to a selfie-only branch and skips the document capture. The effective branch is exposed as `method` (`FACE` or `DOCUMENT`) on the status endpoint.

Adaptive flow needs `externalUserId` to look up the previous verification. If you do not know it at link creation, the user can supply their email mid-flow through `PATCH /verifications/identify`. See [Links](/en/identity-link/links#adaptive-flow).

## Next steps

* Read the [Authentication](/en/identity-link/authentication) guide to make your first authenticated call.
* Work through the [Links](/en/identity-link/links) reference for every endpoint and field.
* Browse [Other Technical Docs (Wiki)](https://wiki.corp.vusecurity.com/es/home) for general product information.


## Related topics

- [Identity Link API Changelog](/en/identity-link/changelog.md)
- [Identity Link API Error Codes and Responses](/en/identity-link/errors.md)
- [Integration guide](/en/vucs/id-analysis/integration.md)
- [Identity Link Webhooks: Verification Lifecycle Events](/en/identity-link/webhooks.md)


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