Standard JWT Claims Reference
iss (Issuer)Identifies the principal that issued the token.
sub (Subject)Identifies the user or identity (e.g. user_id).
aud (Audience)Identifies the intended recipients of the JWT.
exp (Expiration Time)Unix timestamp after which the token expires.
iat (Issued At)Unix timestamp indicating when the token was created.
nbf (Not Before)Timestamp before which the token must not be accepted.