Coupons

Public

POST /api/coupons/validate

No session. Rate limited (~20/window). Used by checkout / embed prefill.

Seller (session + manageCoupons)

Method	Path
GET/POST	/api/coupons
GET/PUT/DELETE

Coupon model fields include code, discount type/value, limits, isActive, validFrom, validUntil (see Prisma order model). Never compute final prices only on the client — server validate wins.