How does JSON differ from JSONB in PostgreSQL?

In PostgreSQL, the data types json and jsonb are used for storing JSON data but have important differences:

• json — stores data as a text string, exactly as it was passed. Data is parsed anew with each query.
• jsonb — stores data in a binary format, optimized for fast access and indexing.

Main differences:

1. Performance

   • jsonb is faster for searching and filtering because data is already indexed and structured.
   • json is slower because it requires parsing the text on each query.

2. Storage

   • jsonb takes up slightly more space due to the binary format, but this is offset by its speed.

3. Index support

   • jsonb supports GIN and GiST indexes, enabling efficient queries by keys and values.
   • json does not support such indexes.

4. Behavior on saving

   • jsonb normalizes data: removes spaces, sorts keys, which may change the original order.
   • json stores data as-is.

Example of using jsonb:

CREATE TABLE example (
    data jsonb
);

INSERT INTO example VALUES ('{"name": "Alice", "age": 30}');

-- Search by key
SELECT * FROM example WHERE data->>'name' = 'Alice';

In most cases, it is recommended to use jsonb due to better performance and functionality.