How do JSON and JSONB differ in PostgreSQL?

In PostgreSQL, the data types JSON and JSONB are used for storing JSON structures but differ in internal representation and performance.

• JSON stores data as text, in the form it was passed. Each query involves parsing the text into a data structure.
• JSONB (Binary JSON) stores data in a binary format, which is already parsed and optimized for fast access and indexing.

Main differences:

• JSONB supports indexes (GIN, GiST), which speeds up content search.
• JSONB takes up slightly more space but is faster to process.
• JSON preserves formatting and key order, JSONB does not.

Example of using JSONB with an index:

CREATE TABLE documents (
  id serial PRIMARY KEY,
  data jsonb
);

CREATE INDEX idx_data ON documents USING gin (data);

SELECT * FROM documents WHERE data @> '{"key": "value"}';

If query speed and searching JSON are important, it is better to use JSONB.