## Authentication

All API requests require a bearer token in the `Authorization` header. You can generate API keys from within your Project Blue dashboard under **Settings → API Keys**.

![API Keys settings in the Project Blue dashboard](https://api.tryprojectblue.com/pb-app/pb_api.png)

> **Keep your API keys secure**
>
> Never expose your API key in client-side code or public repositories. Always make API calls from your server.

**Request — HTTP header**

```http
Authorization: Bearer YOUR_API_KEY
```

**Example — cURL**

```bash
curl -X POST https://api.tryprojectblue.com/send-api-message \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "message": "Hey! Just following up on our conversation.",
    "phone": "+15551234567"
  }'
```