Genuine perfumes have a serial number on both the box and the bottle. You can use tools like CheckFresh to verify the production date.
Retailers like Fragrance Direct and FragranceNet are often called "grey market" sellers. They buy surplus stock and sell it at a discount.
Pay attention to whether you are buying an Eau de Parfum (EDP) , which lasts 6–8 hours, or an Eau de Toilette (EDT) , which is lighter and usually cheaper.
Guaranteed genuine products, better quality control (proper storage), exclusive launches, and brand-specific loyalty rewards. Cons: You will almost always pay full retail price (MSRP).
This is the safest way to ensure 100% authenticity, especially for high-end luxury scents.