Inside every genuine sneaker is a size tag carrying the style code, factory and production dates, size conversions, and a QR or barcode element on modern releases. Authentication communities start there because the tag makes claims that can be checked: does the style code match the colourway in the photos, do the production dates fall before the release date, does the factory code match known production for that model.
Counterfeits copy the tag as an image, so errors creep in: a production date after the shoe supposedly sold, a style code belonging to a different colourway, size conversions that do not line up across US, UK, and EU columns. A listing that refuses a clear tag photo is withholding the single most checkable item in the box, and experienced buyers treat that refusal as information in itself.
Stitching density and consistency, the shape of the toe box and heel, insole print that rubs off too easily, glue work at the midsole, and the smell of adhesives that genuine factories have largely engineered out are the physical tells reviewers catalogue model by model. None is universal, because each release has its own reference points, which is why authentication is model specific knowledge rather than a generic checklist anyone can run once.
Release logic is the listing level check anyone can run. A colourway that sold out at retail, in a full size run, restocked repeatedly by one seller at under retail price, is an arithmetic problem before it is a fashion question. Supply of a genuinely limited shoe does not behave that way. The USTR Notorious Markets List and platform enforcement reports describe the same seller pattern at scale: volume, rotation, and pricing that only counterfeit supply can sustain.
Buyers get the most protection from platforms with authentication services and payment protection, and by insisting on tag and detail photographs for private sales. Keep the transaction on platform. Moving to a private payment at a sellers request removes the only leverage a buyer has when the shoes fail inspection on arrival.
For brands and watch teams, sneaker monitoring is a calendar discipline: new colourways get listing sweeps at release, test buys target the sellers with impossible size runs, and evidence packages lead with tag inconsistencies because they are objective. Report through platform IP channels and preserve seller identifiers across takedowns. In sneakers, the network is the counterfeiter, the listing is just its current window.
If this topic is useful, these earlier guides go deeper on connected questions: Counterfeit Watches in Listings: Authentication Clues for Shoppers, Counterfeit Sunglasses in Listings: Authentication Clues That Survive Photos, and Serial Numbers Settle Arguments That Photos Cannot.
The size tag. Its style code should match the colourway pictured, its production dates should precede the release, and its size conversions should be consistent. A seller who will not show a clear tag photo is withholding the most checkable evidence.
No single tell proves it. Stitching, shape, materials, and glue work support a judgement when several disagree with a known genuine reference for that exact model. Authentication is a consistency pattern across tag data, construction, and seller behaviour.
A genuinely limited, sold out colourway cannot be restocked in every size repeatedly below retail by one seller. That supply pattern only makes economic sense with counterfeit stock, which is why price and size availability together are strong listing level evidence.
Through the platforms intellectual property reporting channel, with tag photographs and comparison evidence where possible. Preserve seller names and identifiers, because repeat sellers reappear under new storefronts after takedowns.