select
  sign(
    payload   := '{"sub":"1234567890","name":"John Doe","iat":1516239022}',
    secret    := 'secret',
    algorithm := 'HS256'
  );
                                                                            sign                                                                             
-------------------------------------------------------------------------------------------------------------------------------------------------------------
 eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.XbPfbIHMI6arZ3Y922BhjWgQzWXcXNrz0ogtVhfEd2o
(1 row)

select
  verify(
    token := 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYW1lIjoiRm9vIn0.Q8hKjuadCEhnCPuqIj9bfLhTh_9QSxshTRsA5Aq4IuM',
    secret    := 'secret',
    algorithm := 'HS256'
  );
                             verify                             
----------------------------------------------------------------
 ("{""alg"":""HS256"",""typ"":""JWT""}","{""name"":""Foo""}",t)
(1 row)