---
title: Track dynamic variables - React Native
description: Learn how to implement dynamic variable tracking to enrich your analytics data in your React Native application with the CSQ SDK
lastUpdated: 14 April 2026
source_url:
  html: https://docs.contentsquare.com/en/csq-sdk-react-native/experience-analytics/track-dynamic-variables/
  md: https://docs.contentsquare.com/en/csq-sdk-react-native/experience-analytics/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, directly use the key and String/Integer value:

```typescript
import { CSQ } from "@contentsquare/react-native-bridge";


CSQ.addDynamicVar("cart_value", 123)
CSQ.addDynamicVar("user_account_status", "premium")
CSQ.addDynamicVar("ab_test_variant", "control")
CSQ.addDynamicVar("session_id", 456789)
```

**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"*

## 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](../data-collection/#session-definition) section for more information.

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

You can use the [`AppState` API ↗](https://reactnative.dev/docs/appstate) 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 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 maximums length 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".