---
title: Track custom variables - iOS (classic)
description: Track custom variables with the Contentsquare iOS SDK
lastUpdated: 14 April 2026
source_url:
  html: https://docs.contentsquare.com/en/ios/track-custom-variables/
  md: https://docs.contentsquare.com/en/ios/track-custom-variables/index.md
---

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

The latest CSQ SDK is here! Learn how to [upgrade your app](https://docs.contentsquare.com/en/csq-sdk-ios/experience-analytics/upgrade-from-cs-sdk/).

Custom variables attach additional information about the screen, user, or session to screenview events. For example, they can include information on the current layout of a screen, like day/night mode.

Warning

**Note about Privacy Manifest:** If you decide to use Custom Variables to collect new data or use already collected data but for a different purpose, it is up to you to update the privacy practices described in your app manifest accordingly. See [Purpose of processing and categories of personal data collected](https://docs.contentsquare.com/en/ios/privacy/#purpose-of-processing-and-categories-of-personal-data-collected) already described in the Contentsquare iOS SDK Privacy Manifest.

## Defining custom variables

To define and send custom variables, follow this:

* Swift

  ```swift
  import ContentsquareModule


  let cvar1 = CustomVar(index: 1, name: "CustomVarName1", value: "CustomVarValue1")
  let cvar2 = CustomVar(index: 2, name: "CustomVarName2", value: "CustomVarValue2")


  Contentsquare.send(screenViewWithName: "ScreenName", cvars: [cvar1, cvar2])
  ```

  Warning

  For consistent analytics, use the same index/name pair values across your application:

  **Screen A**

  ```swift
  let cvar4 = CustomVar(index: 1, name: "hero_banner_type", value: "carousel")
  Contentsquare.send(screenViewWithName: "ScreenA", cvars: [cvar4])
  ```

  **Screen B**

  ```swift
  let cvar4 = CustomVar(index: 1, name: "hero_banner_type", value: "slider")
  Contentsquare.send(screenViewWithName: "ScreenB", cvars: [cvar4])
  ```

* Objective-C

  ```objective-c
  @import ContentsquareModule;


  CustomVar *cvar1 = [[CustomVar alloc] initWithIndex:1
                                          stringName:@"CustomVarName1"
                                          stringValue:@"CustomVarValue1"];
  CustomVar *cvar2 = [[CustomVar alloc] initWithIndex:2
                                          stringName:@"CustomVarName2"
                                          stringValue:@"CustomVarValue2"];


  [Contentsquare sendWithScreenViewWithName:@"ScreenName" cvars:@[cvar1, cvar2]];
  ```

  Warning

  For consistent analytics, use the same index/name pair values across your application:

  **Screen A**

  ```objective-c
  CustomVar *cvar4 = [[CustomVar alloc] initWithIndex:4
                                      stringName:@"hero_banner_type"
                                      stringValue:@"carousel"];


  [Contentsquare sendWithScreenViewWithName:@"ScreenA" cvars:@[cvar4]];
  ```

  **Screen B**

  ```objective-c
  CustomVar *cvar4 = [[CustomVar alloc] initWithIndex:4
                                  stringName:@"hero_banner_type"
                                  stringValue:@"slider"];


  [Contentsquare sendWithScreenViewWithName:@"ScreenB" cvars:@[cvar4]];
  ```

## Limits

### On the server side

* It is possible to save up to 20 distinct custom variables per screenview. If more are received, only the first 20 custom variables, based on their `index` value, will be kept.
* The `index` value of the custom variable is used to determine which custom variables to be kept. Only `index` value between 1 and 20 will be taken into account.

### On the SDK side

* Every custom variable is composed of `index`, `name` and `value`.
* If you are using the same `index` twice in the same screen, only the first (`name`, `value`) pair associated with the `index` will be kept.
* In case `name`(max. 512 characters) or `value`(max. 255 characters) maximum character length is reached, the SDK will automatically trim the exceeding characters.
* If `name` or `value` are empty, the SDK will instead send the literal string `"cs-empty"`.
* Use a consistent index for a given custom var within an application — for instance, if the "screen layout" is collected with an `index` of 3, use the slot 3 for this information on every screen of the application.