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

# Authentication

> Authenticate platform API requests with an organization API key.

All control-plane endpoints on `https://simulation.ressl.ai` require an organization API key.

## Create a key

1. Open [simulation.ressl.ai](https://simulation.ressl.ai) → **Settings**.
2. Create an API key and copy the token immediately.
3. Tokens use the prefix `rsk_` and are never shown again.

Keys are scoped to the organization you are signed into. They can only use providers granted to that org.

## Send the key

<CodeGroup>
  ```bash Bearer theme={"system"}
  curl https://simulation.ressl.ai/providers/list \
    -H "Authorization: Bearer rsk_..."
  ```

  ```bash X-API-Key theme={"system"}
  curl https://simulation.ressl.ai/providers/list \
    -H "X-API-Key: rsk_..."
  ```
</CodeGroup>

## Errors

| Status | Meaning                            |
| ------ | ---------------------------------- |
| `401`  | Missing, malformed, or revoked key |

```json theme={"system"}
{ "error": "Unauthorized" }
```