I have the following sample data for demo:

Table:

create table tbl_json
(
   id json
);

Some values:

insert into tbl_json values('[{"id":1},{"id":2},{"id":3}]');

Query: Convert/cast id into integer from json column.

Tried:

select json_array_elements(id)->>'id'::int ids 
from tbl_json;

Getting an error:

ERROR: invalid input syntax for integer: "id"