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

# Authentication

> How to authenticate with the OpenCompress API.

## API keys

All API requests require authentication via a Bearer token in the `Authorization` header:

```
Authorization: Bearer sk-occ-your-key-here
```

API keys start with the prefix `sk-occ-` followed by a cryptographically random string.

## Getting a key

1. Sign in at [opencompress.ai/dashboard](https://www.opencompress.ai/dashboard)
2. Navigate to the **API Keys** section
3. Click **Create Key**
4. Choose a mode (Router or BYOK)
5. Copy the key immediately — **it's shown only once**

## Key security

<Warning>
  Your API key is shown only once when created. Store it securely. If you lose it, revoke the old key and create a new one.
</Warning>

Best practices:

* Store keys in environment variables, never in code
* Use different keys for development and production
* Revoke keys immediately if compromised
* Each key has independent rate limits and usage tracking

## Key modes

| Mode       | Description                                                                                 |
| ---------- | ------------------------------------------------------------------------------------------- |
| **Router** | OpenCompress routes to the LLM via OpenRouter. You pay us for everything.                   |
| **BYOK**   | Bring your own LLM key. You pay your provider directly; we charge only the compression fee. |

See [BYOK Mode](/features/byok-mode) for setup details.

## Key management

* **Maximum keys:** 5 active keys per account
* **Revoke:** Delete a key in the dashboard. Takes effect immediately.
* **Last used:** Dashboard shows when each key was last used