---
title: Track dynamic variables - WebView
description: Track dynamic variables in your apps using the Web Tracking Tag
lastUpdated: 27 April 2025
source_url:
  html: https://docs.contentsquare.com/en/webview-tracking-tag/track-dynamic-variables/
  md: https://docs.contentsquare.com/en/webview-tracking-tag/track-dynamic-variables/index.md
---

## General principles

### Usage

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.

### Limits

#### On the server side

* It is possible to save up to 40 distinct dynamic variable keys per screenview. If more are received, only the first 40 keys will be kept.
* If you are using the same key twice on the same screenview, 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. 50 characters) and value (max. 255 characters string or number of type `Long` between 0 and 232 - 1). In case these maximum lengths are reached, the SDK will automatically trim the exceeding characters.
* If key or value are empty, the SDK will instead send the literal string "cs-empty".

## Defining dynamic variables

To define and send a dynamic variable, directly use the key and String/Long value **once a first screenview has been triggered**:

```javascript
window._uxa = window._uxa || [];
window._uxa.push(["trackDynamicVariable", { key: my_key, value: my_value }]);
// key is a string
// value is either a string or an integer
```

**Type of the value** — The value can be either a **whole number** or a **string**. For each case, available features won't be the same in the Contentsquare app:

* For **whole numbers**, you will be able to do some algebra. Example: *sessions with dynamic variable key = "numberOfFriends" and value >= 10*
* For **strings**, auto-completion and Regular Expression will be available. Example: *sessions with dynamic variable key = "accountType" and value = "Premium"*