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

# Authentication

> How to authenticate with the GreetIncs API

## API Key Authentication

All API requests (except the health check endpoint) require authentication via an API key.

### Getting an API Key

API keys are issued through your GreetIncs dashboard. Keys follow the format:

```
greetincs_...
```

### Using Your API Key

Include your API key in the `X-API-Key` header with every request:

```bash theme={null}
curl -X GET "https://api.greetincs.com/v1/analyses/" \
  -H "X-API-Key: greetincs_your_api_key"
```

### Security Best Practices

<Warning>
  Never expose your API key in client-side code, public repositories, or logs.
</Warning>

* Store API keys in environment variables or secrets managers
* Use different keys for development and production
* Rotate keys periodically
* Revoke compromised keys immediately

### Error Responses

| Status | Meaning                                              |
| ------ | ---------------------------------------------------- |
| 401    | Missing or invalid API key                           |
| 402    | Payment required - check your account status         |
| 403    | API key valid but lacks permission for this resource |