---
title: 1:1 Validation
description: Capability that confirms the current face is the same one used in a reference process. Typical of transactional flows.
canonical: https://developer.unico.io/dual-api/capabilities/1-1-validation
locale: en
generated_by: markdown-export
---

When the user has already gone through onboarding, 1:1 Validation confirms that whoever is in front of the camera in this transaction is the same person from the initial registration.

### What it does

Compares the selfie captured in the current session against the selfie captured in a previous process — referenced by that process's identifier. Returns a binary verdict (same person or not), with no probabilistic score.

### Inputs

- A capture session opened via [`POST /v1/process`](/dual-api/developers/api-reference/web-sdk) with a flow that includes 1:1 Validation.
- **Reference process identifier** (the original registration / onboarding to which this validation will be compared).

### Possible responses

| Response | Meaning |
|---|---|
| `YES` | The face is the same as in the reference process. |
| `NO` | The face is not the same as in the reference process. |

### Availability

| Surface | Supported |
|---|:-:|
| **SDK** (Android, iOS, Flutter) | ✅ |
| **Web** (iFrame, Redirect) | ✅ |
| **API** (headless, no SDK) | ✅ |

### Valid combinations

1:1 Validation appears in flows that include the `token` suffix:

`idtoken`, `idtokentrust`, `idtokensign`.

For the full matrix, see [Available flows](/dual-api/capabilities/available-flows).

### 1:1 Validation vs Smart Revalidation

Both 1:1 Validation and [Smart Revalidation](/capabilities/smart-revalidation) address the question "is this the same person from the registration?". The difference:

- **1:1 Validation** always requires a new active selfie to compare with the reference.
- **Smart Revalidation** orchestrates multiple authentication tiers (metadata, silent authentication, passkey, facial biometric) adaptively, choosing the least-friction approach for each transaction based on real-time risk signals.

When biometrics are not regulatory-mandated, Smart Revalidation reduces friction. When biometrics are mandatory, use 1:1 Validation.