# SignupChallenge

> The SignupChallenge object in the Guv API.

## Fields

| Field | Type | Description |
| --- | --- | --- |
| `challenge` * | string |  |
| `algorithm` * | string |  |
| `difficulty_bits` * | integer |  |
| `expires_at` * | string (date-time) |  |

\* always present

## Example

```json
{
  "challenge": "string",
  "algorithm": "string",
  "difficulty_bits": 1,
  "expires_at": "2026-10-22T13:05:00Z"
}
```

## Used by

- [Get a proof-of-work challenge](/docs/api/sign-up/#get-a-proof-of-work-challenge)