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> Reference material for JSON_IS_VALID function

# JSON_IS_VALID

Returns whether the input string is a valid JSON document.
Returns `NULL` if the input is `NULL`.

## Syntax

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
JSON_IS_VALID(<json_string>)
```

### Aliases

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
JSON_VALID(<json_string>)
```

## Parameters

| Parameter       | Description                     | Supported input types |
| :-------------- | :------------------------------ | :-------------------- |
| `<json_string>` | The string to validate as JSON. | `TEXT`                |

## Return Type

The `JSON_IS_VALID` function returns a result of type `BOOL`.

## Remarks

If you want to know why the input string is invalid JSON, you can also use the [`CHECK_JSON`](/reference-sql/functions-reference/json/check-json) function.

## Examples

**Example**

The following code example validates a simple JSON string:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT JSON_IS_VALID('{"name": "John"}');
```

**Returns**: `TRUE`

The previous code example returns `TRUE` because the input string is valid JSON.

**Example**

The following code example validates a simple JSON string:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT JSON_IS_VALID('{"name": "John"}{"name": "John"}');
```

**Returns**: `FALSE`

The previous code example returns `FALSE` because the input string is invalid JSON as it contains two JSON objects next to each other.