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

# json.isNull

> Returns whether a value is Real's JSON null sentinel, json.null.

Returns whether a value is Real's JSON null sentinel, json.null.

## Syntax

```lua theme={null}
json.isNull(value: any): boolean
```

## Arguments

| Name    | Type  | Required | Description                                                                                     |
| ------- | ----- | -------- | ----------------------------------------------------------------------------------------------- |
| `value` | `any` | Yes      | Value to inspect. Only the json.null value returns true; Lua nil and other values return false. |

## Returns

| Name     | Type      | Description                                                           |
| -------- | --------- | --------------------------------------------------------------------- |
| `isNull` | `boolean` | true when the value is the exact json.null sentinel, otherwise false. |

## Example

Check whether a value is the json.null sentinel instead of Lua nil.

```lua theme={null}
local value = json.decode("null")

if json.isNull(value) then
    print("The value is JSON null")
end

print(json.isNull(nil))
```