In which cases is it recommended to use the JSON format for storing data in a PostgreSQL database?

The JSON format in PostgreSQL is recommended when the data structure can be flexible or variable, and the exact schema is unknown in advance. It is convenient for storing nested objects, lists, or when you need to quickly save and retrieve data without complex relationships. For example, if you have user settings or metadata that may differ across records, JSON allows storing them in a single field and using PostgreSQL's built-in functions for searching and filtering.

Example of using JSONB in PostgreSQL:

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name TEXT,
  preferences JSONB
);

INSERT INTO users (name, preferences) VALUES
('Ivan', '{"theme": "dark", "notifications": true}');

-- Find users with dark theme
SELECT * FROM users WHERE preferences->>'theme' = 'dark';

Thus, JSON is suitable for dynamic data, but if the structure is fixed and performance is important, it is better to use regular columns.