> ## Documentation Index
> Fetch the complete documentation index at: https://docs.reelevant.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Replace with Variable

> Replace text using a variable value

## Overview

The `replace-var` transformation replaces text in a string using a variable value as the replacement.

## Syntax

```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
replace-var(<variable>, <replace-variable>, search="", isRegex=false)
```

## Parameters

| Parameter          | Type     | Required | Description                                         |
| ------------------ | -------- | -------- | --------------------------------------------------- |
| `variable`         | string   | Yes      | The string to search in                             |
| `replace-variable` | variable | Yes      | The variable whose value is used as the replacement |
| `search`           | string   | Yes      | The substring or regex pattern to find              |
| `isRegex`          | boolean  | Yes      | Whether the search string is a regular expression   |

## Examples

```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
replace-var(<variable>, <replace-variable>, search="placeholder", isRegex=false)
replace-var(<variable>, <replace-variable>, search="[0-9]+", isRegex=true)
```

<Info>
  This is similar to the [Replace](/advanced-guide/transformations/replace) transformation, but uses a variable for the replacement value instead of a static string.
</Info>