JSON is widely used in modern applications. API responses, configuration data, flexible fields and external system payloads are often represented as JSON. SQL Server provides several functions for working with JSON data.

SQL Server does not have a separate JSON data type. JSON values are usually stored in nvarchar columns. However, functions such as JSON_VALUE, JSON_QUERY and OPENJSON allow reading and querying JSON content.

JSON_VALUE is used to read scalar values. For example, a username or status value inside a JSON document can be extracted easily. JSON_QUERY is used for returning objects or arrays.

OPENJSON is useful for converting JSON arrays into rows. It is powerful when processing JSON data received from external systems.

JSON should not replace relational modeling. Data that is frequently queried, related or reported should usually be stored in normal tables. JSON is best for flexible or auxiliary data structures.