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

# Authentication

> How to authenticate with the Saturn API

All API requests (except signup and health) require authentication via Bearer token.

## Authentication Header

Include your API key in the `Authorization` header:

```bash theme={null}
Authorization: Bearer sk_agt_your_api_key_here
```

## Example Request

```bash theme={null}
curl https://api.saturn-pay.com/v1/wallet \
  -H "Authorization: Bearer sk_agt_abc123def456..."
```

## API Key Format

Saturn API keys follow this format:

```
sk_agt_[32 random characters]
```

* `sk_` — Secret key prefix
* `agt_` — Agent key identifier
* `[32 chars]` — Unique identifier

## Getting an API Key

### Option 1: Signup (New Account)

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.saturn-pay.com/v1/signup \
    -H "Content-Type: application/json" \
    -d '{"name": "my-agent"}'
  ```

  ```typescript SDK theme={null}
  const { saturn, apiKey } = await Saturn.signup({
    name: 'my-agent'
  });
  ```
</CodeGroup>

**Response:**

```json theme={null}
{
  "apiKey": "sk_agt_abc123...",
  "agentId": "agt_xyz789",
  "accountId": "acc_123456"
}
```

### Option 2: Create Agent (Existing Account)

```bash theme={null}
curl -X POST https://api.saturn-pay.com/v1/agents \
  -H "Authorization: Bearer sk_agt_your_existing_key" \
  -H "Content-Type: application/json" \
  -d '{"name": "worker-2"}'
```

## Error Responses

### 401 Unauthorized

Missing or invalid API key:

```json theme={null}
{
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Invalid or missing API key"
  }
}
```

### 403 Forbidden

Valid key but agent is killed or lacks permission:

```json theme={null}
{
  "error": {
    "code": "AGENT_KILLED",
    "message": "Agent has been disabled"
  }
}
```