---
title: "jsonSet"
description: "Takes a JSON friendly string, a path string, and value, and will return a new JSON friendly string with the provided path set to the provided value."
---

# jsonSet

> Takes a JSON friendly string, a path string, and value, and will return a new JSON friendly string with the provided path set to the provided value.

**This function is used by Ignition's Expression language.**
## Description
Takes a JSON-friendly string, a path string, and value, and will return a new JSON-friendly string with the provided path set to the provided value. This is best used in conjunction with the [Derived Tags](platform\tags\types-of-tags\types-of-tags.md#derived-tags) writeback value.

## Syntax
` jsonSet(json, path, value)`

### Parameters

| Type | Parameter | Description |
|---|---|---|
| String | `json` | The JSON string. The string must be in a JSON friendly format. |
| String | `path` | The path string. |
| Object | `value` | The replacement for the value at the path. | 

### Results
**String** - A JSON friendly string with a new value set at the specified path.

## Examples
```python title="Code Snippet"
// This example takes a JSON friendly string and sets the provided path to the given value. This would then return the string {'item':{'firstThing':1, 'secondThing':5}}
 
jsonSet("{'item':{'firstThing':1, 'secondThing':2}}", "item.secondThing", 5)
```