# Authentication

## API Host

All API requests should be sent to the following host:

`apiv2.retainful.net`

## Headers

All requests to Retainful’s API must include the following HTTP headers:

| `Retainful-Api-Key` | Your Retainful API Key. Keep this credential confidential. |
| ------------------- | ---------------------------------------------------------- |
| `Retainful-App-Id`  | Your Retainful App ID.                                     |

## Example Request with Headers

```
POST /v2/contacts
Host: apiv2.retainful.net
Retainful-Api-Key: <YOUR_API_KEY>
Retainful-App-Id: <YOUR_APP_ID>
Content-Type: application/json

```