Authenticity cannot be settled on a video call. This is the category counterfeiters work hardest at, which means it is also the category where a confident checklist does the most harm.
What to ask them to show
The interior stamp or marking, in focus. Ask for it close, square on, and well lit — not as part of a wider shot.
Any serial, date or batch marking, photographed. Whatever it is, a photograph of it can be looked at later by somebody who knows what it should be. You do not need to know yourself in the moment.
The hardware, close up, and ask them to let a zip run.
The lining, including a corner where it meets a seam.
The base and its corners, which is where wear shows honestly.
The dust bag, box and any paperwork — photographed, not listed.
What a refusal means
In this category what exposes a fake is a seller’s behaviour rather than any detail of the stitching. A seller with nothing to hide has usually photographed it carefully already, and will happily add one more picture. A seller who answers "everything is in the listing photographs" to a specific request has declined to produce the one thing you asked for.
"It is 100% authentic, I have the receipt" with no photograph of the receipt is the commonest version of this.
What this page will not do
It will not describe stitching, hardware weight or how a logo should sit. Those details are precisely what good counterfeits copy next, and a page naming them is a page teaching a buyer to be reassured by the wrong thing.
If the bag is expensive, the sensible path is photographs good enough for an authentication service, obtained before you bid rather than after.
What protects you if you get it wrong
A counterfeit is not as described — returnable for 7 days whatever the store's policy says — and it is reportable. Counterfeits are banned here outright, and reports are acted on.
Questions people ask
Does Metzee authenticate bags?
No. Nothing passes through us.
Is a receipt proof?
A photograph of a receipt is a piece of evidence. Receipts are also faked, and a receipt does not travel with the bag's identity.
What about an honest replica, sold as one?
Selling something as a replica is a different thing from selling it as genuine, and it must say so plainly in the listing.
More: spotting a counterfeit before you bid, Metzee's position on counterfeits, reporting a seller, questions to ask before bidding on a bag.