---
title: Capture API
canonical: https://developer.unico.io/dual-api/developers/sdks-and-tools/flutter/api-reference/capture-api
locale: en
generated_by: markdown-export
---

- [/](/)
- [SDKs and Tools](/dual-api/developers/sdks-and-tools/overview)
- [Flutter SDK](/dual-api/developers/sdks-and-tools/flutter/requirements)
- API Reference
- Capture API

# Capture API

Methods to start a session
| Method | Description |
| --- | --- |
| `openCameraSelfie({listener})` | Opens the selfie camera |
| `openCameraSelfie({listener, prepareInfo})` | Opens the selfie camera with `UnicoCheckPrepareInfo` metadata |
| `openCameraDocument({documentType, listener})` | Opens the document camera with the desired `DocumentCameraTypes` |

Capture options / parameters
**`UnicoCheckPrepareInfo`** — metadata to identify the user session.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `externalUserId` | `String` | yes | User identifier within your system. Hashed with SHA-256 before transmission. |
| `useCase` | `String` | no | Identifier for the context or flow currently running. Transmitted in plain text. |

**`DocumentCameraTypes`** — see [Enums](/developers/sdks-and-tools/flutter/api-reference/enums).

Result types and fields
**`ResultCamera`** — object returned on successful capture (selfie or document).

| Field | Type | Description |
| --- | --- | --- |
| `base64` | `String` | Captured image in Base64 |
| `encrypted` | `String` | JWT to be sent to the backend |

Last updated on **Oct 8, 2026**