Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# IS\$1VALID\$1JSON function
<a name="IS_VALID_JSON"></a>

**Note**  
CAN\$1JSON\$1PARSE and its associated functions parse JSON values as SUPER, which Amazon Redshift parses more efficiently than VARCHAR.  
 Instead of using IS\$1VALID\$1JSON, we recommend that you validate your JSON strings using the [CAN\$1JSON\$1PARSE function](CAN_JSON_PARSE.md). 

The IS\$1VALID\$1JSON function validates a JSON string. The function returns Boolean `true` if the string is properly formed JSON or `false` if the string is malformed. To validate a JSON array, use [IS\$1VALID\$1JSON\$1ARRAY function](IS_VALID_JSON_ARRAY.md)

For more information, see [JSON functions](json-functions.md). 

## Syntax
<a name="IS_VALID_JSON-synopsis"></a>

```
IS_VALID_JSON('json_string')
```

## Arguments
<a name="IS_VALID_JSON-arguments"></a>

 *json\$1string*  
A string or expression that evaluates to a JSON string.

## Return type
<a name="IS_VALID_JSON-return"></a>

`BOOLEAN`

## Examples
<a name="IS_VALID_JSON-examples"></a>

To create a table and insert JSON strings for testing, use the following example.

```
CREATE TABLE test_json(id int IDENTITY(0,1), json_strings VARCHAR);

-- Insert valid JSON strings --
INSERT INTO test_json(json_strings) VALUES
('{"a":2}'), 
('{"a":{"b":{"c":1}}}'), 
('{"a": [1,2,"b"]}');

-- Insert invalid JSON strings --
INSERT INTO test_json(json_strings) VALUES
('{{}}'), 
('{1:"a"}'), 
('[1,2,3]');
```

To validate the strings in the preceding example, use the following example.

```
SELECT id, json_strings, IS_VALID_JSON(json_strings) 
FROM test_json
ORDER BY id;

+----+---------------------+---------------+
| id |    json_strings     | is_valid_json |
+----+---------------------+---------------+
|  0 | {"a":2}             | true          |
|  4 | {"a":{"b":{"c":1}}} | true          |
|  8 | {"a": [1,2,"b"]}    | true          |
| 12 | {{}}                | false         |
| 16 | {1:"a"}             | false         |
| 20 | [1,2,3]             | false         |
+----+---------------------+---------------+
```