To improve reliability, the Ship&co API / shipments endpoint now enforces tighter validation. Requests that fail any rule are rejected with descriptive error messages.
Key changes
setup.pack_size — must be an integer (e.g., 80); strings like "80" are invalid.
setup.print_start_location — must be an integer for A4 label services (yuupacket_regular, yuumail_regular, yamato_direct_mail, yamato_nekopos, yamato_kuroneko_yuupacket).
products.hs_code — if supplied, must be 6–15 digits; omit the field entirely if no code is available.
customs.duty_paid & customs.content_type — these fields must live inside the customs object, not inside setup.
