When testing a table with a SERIAL field, this number will grow even if you remove all items in the table (like you’d do during testing), so you might insert a value and its id is 15 for example.

To restart the sequence from 1, run the SQL query:

ALTER SEQUENCE TABLENAME_id_seq RESTART

Replace TABLENAME with your table name, like:

ALTER SEQUENCE users_id_seq RESTART

Using TablePlus you have the option to reset the sequence when you truncate a table to remove its content.