# Testing

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This section is essential for verifying the functionality of different parameters and ensuring proper communication between the device and the platform.

### API

The API section provides options to get or update the values of datastreams, set properties, and log events.

#### **API Command Tabs**

* **GET value:** Retrieve the current value of a specific datastream.
* **UPDATE value:** Update the value of a specific datastream.
* **Set property:** Modify the properties of a datastream.
* **Log event:** Record events related to the datastream.

#### **Datastream Selection**

Allows the selection of a specific datastream to interact with from a dropdown menu (e.g., `Humidity (V4)`).

**Data Type and Range:** Displays the hint on the data type and acceptable range for the selected datastream (e.g., `Double. Range: 0-100`).

#### **Value Input and Update**

For Update value, Set property options you can enter a new value to update the datastream ().

You can also update multiple datastreams / properties usind *Add* button.

#### Code Snippets

The section provides code snippets for [firmware API](https://docs.blynk.io/en/blynk-library-firmware-api), [HTTP API](https://docs.blynk.io/en/blynk.cloud/device-https-api) and [MQTT API](https://docs.blynk.io/en/blynk.cloud-mqtt-api/device-mqtt-api) that can be used to perform the actions that were configured in the interface above from the hardware.

{% hint style="info" %}
Use Timers to send data in intervals. Don’t place `Blynk.virtualWrite` command directly into `void loop().` [Read documentation here](https://docs.blynk.io/en/getting-started/how-to-display-any-sensor-data-in-blynk-app#use-timers).
{% endhint %}