# Request Fields

Send the request as `application/json`.

| Field | Type | Required | Validation |
| --- | --- | --- | --- |
| `transaction_id` | string | Yes | 1–255 characters; letters, digits, hyphens, and underscores only. |
| `face1` | string | Yes | Raw Base64-encoded JPEG, JPG, or PNG image. The decoded image must remain within the upload limit configured for your integration. |
| `face2` | string | Yes | Raw Base64-encoded JPEG, JPG, or PNG image. The decoded image must remain within the upload limit configured for your integration. |

```json
{
  "transaction_id": "face-compare-001",
  "face1": "/9j/4AAQSkZJRgABAQAAAQABAAD...",
  "face2": "/9j/4AAQSkZJRgABAQAAAQABAAD..."
}
```

Send Base64 values without a `data:image/...;base64,` prefix. Face Compare API
v1 validates each image's Base64 data, decoded file size, and detected image
type. It does not apply a documented pixel-dimension requirement.