# Configuration with a custom server

The Efento Gateway sends data to external systems using a **REST API** over **HTTP or HTTPS**, depending on your configuration. Data is delivered to the selected endpoints in JSON format. The full API documentation is available [here](/efento-gateways/integration/api-documentation.md).

To configure the gateway to work with your custom server, follow the steps below:

{% stepper %}
{% step %}

### **Select “Custom settings” as the connection type**

In the **Settings > Server > Connection to server** field, choose **Custom settings**. This enables manual configuration of server parameters instead of using Efento Cloud defaults.

<figure><img src="/files/UsdcRFSZDetch5V5tc95" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### **Configure the server address and port**

Enter the **server URL or IP address** and the **port number** your application uses to receive data. Ensure that the server is accessible from the network the gateway is connected to.

<figure><img src="/files/vJSahOqbmIsTv3kMJ9Ca" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### **Enable or disable TLS**

Choose whether the communication should use **TLS encryption**.

{% hint style="info" %}
We strongly recommend **enabling TLS** to ensure secure, encrypted data transmission and protect your infrastructure from unauthorized access. If required, you can add [custom CA certificates](/efento-gateways/ethernet-gateway/other-settings.md#custom-ca-certificates).
{% endhint %}
{% endstep %}

{% step %}

### **Enable measurements buffering**

Set the toggle next to **Synchronize with server** to **ON**.\
When enabled, the gateway will **buffer logger measurements in its internal memory** and **automatically resend all missing data** to the server after a temporary connection loss. This ensures continuity of data even when the network or server is unavailable for a period of time.
{% endstep %}

{% step %}

### **Optionally configure authentication and custom endpoint**

* You may enter a value in the **Token** field. This value will be included in the HTTP headers of **every message** sent by the gateway, allowing you to implement simple authentication or routing logic on your server.
* Additionally, you can **optionally set a custom endpoint** (path) where the gateway should send measurement and heartbeat messages, if your server does not use the default API paths.
  {% endstep %}
  {% endstepper %}

## Optional configuration parameters

### Heartbeat

The Efento Gateway can send **heartbeat messages** to a user-defined endpoint at regular intervals. These messages allow the server to monitor the gateway’s status, including whether it is online, its uptime, and the number of loggers within range.

<figure><img src="/files/XMjEg9T5tSOM8aNEUqZZ" alt=""><figcaption></figcaption></figure>

To enable heartbeat messages:

1. Toggle the switch next to **“Send heartbeat messages”** to **ON**.
2. Specify the **endpoint** where the messages should be sent. By default the heart beat messages are sent to **/api/v2/gateways/heartbeat**.
3. Set the **time interval** (in minutes) for sending the heartbeat messages.

The structure and details of the heartbeat message payload are described in the [**API Documentation**](/efento-gateways/integration/api-documentation.md#heartbeat) section of this manual.

### Custom HTTP  headers

By default, the Efento Gateway includes the value from the **“Token”** field in the HTTP "X-Api-Token" header. The default headers are:

```http
Content-Type: application/json
charset=UTF-8
X-Api-Token: <value of the “Token” field>
```

If needed, you can configure the gateway to use **custom headers that will overwrite the default "X-Api-Token" header**. To do this, enable the **“Custom headers”** toggle and add the desired header names and values. You can define **up to ten custom headers**, which will be sent in the same order as they appear in the list. The headers **“Content-Type”** and **“charset”** are always included automatically.

<figure><img src="/files/TvATHoblDPTDrDub0WPF" alt=""><figcaption></figcaption></figure>

For example, if you add a custom header named **“Token”** with the value **“sdffsWED34sdfFG6wddV3”**, the gateway will send:

```http
Content-Type: application/json
charset=UTF-8
Token: sdffsWED34sdfFG6wddV3
```

{% hint style="warning" %}
**Important:** The server’s response to the gateway must not contain more than **ten headers**. If the response includes more than ten, the gateway will treat it as invalid and reject the message.
{% endhint %}

## **Hands-on tutorial: Build a server for Efento Gateways**

If you want to see a complete, working example of how to receive measurements from Efento Gateways and store them in a database, make sure to check out our [step-by-step tutorial](/efento-gateways/integration/example-server-application-in-python.md). It includes sample Python code, a simple server application, and instructions for saving incoming data to PostgreSQL - perfect as a starting point for your own integration.


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