While there's no golden universal standard, these are some of the codes that you might find in your booking system:
Discount Economy: K, L, Q, V, U, T, X, N, O, S
Full Fare Economy: Y, B, M, H
Premium Economy: W, E
Discounted Business: D, I, Z
Full Fare Business: J, C
First: A, F
At StaffTraveler, we try to keep things simple, universal, and understandable for everybody. That's why we don't use these confusing codes but easy-to-read classes. Please sum all available Economy (ECO), Premium Economy (ECO+), Business Class (BUS), and First Class (FIRST) seats, then enter the totals in the corresponding boxes in the StaffTraveler app.