---
title: Track dynamic variables - Capacitor
description: Track dynamic variables with the Contentsquare SDKs and Capacitor
lastUpdated: 14 April 2026
source_url:
  html: https://docs.contentsquare.com/en/capacitor/track-dynamic-variables/
  md: https://docs.contentsquare.com/en/capacitor/track-dynamic-variables/index.md
---

> Documentation index: https://docs.contentsquare.com/llms.txt
> Use this file to discover all available pages before exploring further.

Dynamic variables are additional information on the session that can be used to segment sessions.

For example, they can include information on the A/B Test variations displayed to the current user.

## Defining dynamic variables

To define and send a dynamic variable, use the API below. For each dynamic variable, we send:

* Key (`string`, mandatory)
* Value (`string` or `integer`, mandatory)

if you send an integer as a value, it has indeed to be an integer. A null or a float will not be accepted as a valid parameter, and will result in an error.

```javascript
import { ContentsquarePlugin, DynamicVarItem } from '@contentsquare/capacitor-plugin';


const myDynamicVar: DynamicVarItem = {
    dynVarKey: 'myKey',
    dynVarValue: 32,
}


ContentsquarePlugin.sendDynamicVar(myDynamicVar)
  .catch(err => {
        // Handle Error
    });
```

## Sending a dynamic variable for each session

You may want to send a dynamic variable for each session (like the user's country or store). While **triggering the dynamic variable at app launch will cover most cases, it will not be enough**. A session can start when the app is put in foreground, after staying in background for more than 30 minutes. See [Session definition](https://docs.contentsquare.com/en/capacitor/how-the-sdk-works/#session-definition) for more information.

That is why we also recommend **sending such dynamic variable every time the app enters foreground**.

You can use the [`appStateChange` event ↗](https://capacitorjs.com/docs/apis/app) triggered by Capacitor to detect foreground and trigger a dynamic variable.

## Limits

### On the server side

* It is possible to save up to 40 distinct dynamic variable keys per screen view. If more are received, only the first 40 keys will be kept.
* If you are using the same key twice, the last value associated with the key will be collected.

### On the SDK side

* Every dynamic variable is composed of a pair of key (max. 512 characters) and value (max. 255 characters string or a whole number between 0 and 232 - 1 ). The SDK will trim the exceeding characters.
* If key or value is empty, the SDK will send the string "cs-empty".