How to sell sneakers online without authentication and sizing fights

You listed a pair at $230, someone asked "legit check?", and now you're taking photos of a tongue tag at midnight trying to prove a negative. Then the pair you sold last week comes back because a US 10 in one model apparently isn't a US 10 in another.

Both of those are solvable, and both are solved before the sale rather than after it. Proof beats the word authentic, so publish the evidence in the listing instead of promising anything. And publish the insole length in centimetres next to the size, because the single biggest cause of "they don't fit" is a buyer ordering their usual number in a model that runs differently. Two habits. They cost you ten minutes a pair and they remove most of the arguments in this trade.

The rest is inventory discipline, a returns policy you wrote before you needed it, and knowing that on a $220 pair your real costs are around $28 before you've eaten a single return.

Nobody believes the word authentic, so stop using it

Every fake seller writes "100% authentic". The phrase carries no information, which is exactly why buyers ignore it and ask for photos instead.

What carries information is provenance and detail. Replace the adjective with evidence:

• Where it came from and when. "Bought from the Nike app on 14 March 2026, order confirmation available." A dated receipt, even partly redacted, ends most conversations.
• The style code in two places. The code on the box label and the code on the tongue tag or the inside label must match. Photograph both in one shot if you can. This is the fastest check anyone does and it catches a lot.
• The size run on the tag. US, UK, EU and CM are all printed on most sneaker tags. Photograph the whole tag, not a crop.
• The box label, which carries the style code, colourway, size and usually a production date.
• The unflattering angles. Heel counter, stitching along the collar, the outsole tread, the insole lifted at the heel so the underside shows.

Ten photographs, in the same order, every time. Build the habit and it takes four minutes.

The photos a buyer would need to post you to a legit-check thread are the photos that belong in your listing. Put them there and the thread comes back clean before anyone has typed a word.

Two things not to do. Don't authenticate for other people. Someone will send you photos of a pair they're about to buy and ask if it's real, and if you say yes and it isn't, you've bought yourself an enemy for free. And don't sell a pair you can't account for. If you bought it from a stranger at a car park and you're 90% sure, that 10% is not worth $230 and a chargeback.

If you deal in genuinely hyped pairs, the big consignment marketplaces will authenticate on your behalf and take a meaningful cut for it, in the double digits by the time you count seller fees and payment processing. Check their current rate card yourself rather than taking a number from a blog, because those rates change. The trade is straightforward: you pay a lot of your margin to make the authenticity question somebody else's problem. For a $600 pair that can be worth it. For a $130 pair it isn't, which is why the low end of the market lives on personal reputation and photographs.

Building that reputation is slow and it's mostly the boring stuff, covered properly in proving you are a real seller. A name, a face, a consistent handle, and two years of the same photos in the same order.

Publish the length in centimetres

Sizing disputes are not the buyer being difficult. They're a measurement problem you can fix with a ruler.

The same nominal size is not the same shoe across brands or across models within a brand. Runners, skate shoes, basketball silhouettes and retro models from the same manufacturer fit differently, and someone who wears a 10 in one has learned to buy a 10.5 in another. Sizing charts don't capture this. Length in centimetres does.

So do this on every listing:

1. Pull the insole out. Lay it flat against a tape measure. Record the length in cm, heel to toe.
2. If the insole is glued in, measure the internal length from the inside of the heel to the inside of the toe with the tape pressed flat.
3. Put it in the title area of the description, not buried: "US 10 / UK 9 / EU 44. Insole measures 28.0 cm."
4. Photograph the size tag as your second image, after the hero shot.

Then add one line of honest guidance about that specific model. "These run about half a size small, most people size up." If you don't know, say you don't know and give the measurement.

The other sizing traps, in the order they'll get you:

Men's and women's numbering. A women's US 9.5 and a men's US 8 are frequently the same shoe. If you list "size 9.5" without saying which, you have a return coming. Write "W9.5" or "M8" every time.

Converting regions. If the tag says UK 9 and you list a US 10 because a chart told you, say you converted. When it doesn't fit, you want the buyer arguing with the chart rather than with you.

Kids' and grade school sizes. A GS pair is not an adult pair with a smaller number. Say GS in the title.

Wide feet. Some models are famously narrow. Mentioning it costs a sale occasionally and prevents a return regularly, and a return costs more than the sale was worth.

Managing all of this across a shop where every pair is a one-off is fiddly, and how to handle sizes and variants covers how to structure it so you're not rewriting the same paragraph forty times.

Grade the condition in your own words, with photographs of the flaws

The scene has its own shorthand. DS for deadstock, VNDS for very near deadstock, and a rough numbers-out-of-ten scale that means different things to different people.

Use the shorthand if your buyers use it, but never rely on it alone. Write a plain sentence and photograph the wear:

Grade	What you write	What you must photograph
Deadstock	Never worn, original box and laces, all inserts present	Box label, unworn sole, inside heel
Very near deadstock	Tried on indoors only, no creasing, sole clean	Toe box under raking light, outsole
Used, excellent	Worn a handful of times, light toe creasing, clean sole	The creasing, straight on
Used, good	Regular wear, creasing, some heel drag, midsole intact	Every flaw, individually
Beaters	Heavy wear, sold as such, priced as such	All of it, honestly

Shoot the toe box with light coming across it rather than at it, because creasing is invisible in flat light and obvious in raking light. A buyer who finds creasing you didn't photograph assumes you hid it. A buyer who sees it in your photo and buys anyway has agreed to it, and that agreement is what protects you later.

Yellowing on clear or icy soles is worth its own line. It happens with age and light exposure, it's normal on older pairs, and it's the thing most likely to disappoint someone who only looked at the hero shot. Photograph the sole against white paper so the tone is honest.

What a $220 pair actually costs you

Resale margins look better in your head than in your bank account.

Line	Amount	Note
Sale price	$220
Cost of the pair	$145	Retail, raffle win, outlet, or a private buy
Outbound shipping	$14.50	Shoe box inside an outer box, dimensional weight bites
Outer box and filler	$1.80
Card processing	$6.68	A typical 2.9% plus 30c card rate, check your own
Sailo card commission	$1.10	1–3% of the goods, after discount, excluding delivery and tax
Net before returns	$50.92	23% of the sale price

Now the part that decides whether this is a business. One return in ten wipes out roughly a fifth of that. One chargeback on a $220 pair wipes out four sales. A pair that sits for eight months has cost you the money you could have rolled into three faster pairs.

The two levers are the buy price and the hold time, and neither is glamorous. People who make money at this are boring about what they pay and ruthless about cutting pairs that don't move in ninety days.

One shipping habit worth more than it looks: never use the shoe box as the shipping box. For anything collectible the box is part of what was sold, and a shoe box with a courier label taped over the artwork and a corner crushed is a legitimate complaint. Outer box, always, with the shoe box wrapped inside. It costs $1.80 and it removes a whole category of message.

Worked example: Marcus, Atlanta, four to six pairs a week

Marcus started with three pairs he didn't want and now moves four to six a week. Nothing hyped, mostly popular running and lifestyle models in the $110 to $260 range, bought from outlet runs, end-of-season sales, and people locally clearing out.

His average sale is $186 and his average buy is $121. After shipping, packaging and card fees he nets around $44 a pair, so a five-pair week is about $220 for maybe nine hours of buying, photographing, listing, answering messages and driving to the drop-off. Roughly $24 an hour, which he's fine with because a lot of the buying happens while he's doing something else.

His three rules, all learned expensively:

He buys sizes 9 to 11.5 and almost nothing else. His first year he bought whatever was cheap, ended up with four pairs in size 13 and two in size 7, and sat on them for eleven months. The middle sizes sell in days. The outliers sell at a discount to a smaller pool of people.

He photographs every pair laid out on the same grey towel, in the same ten shots, and he photographs the sealed box with the shipping label on it before it leaves the house. That last photo has won him two disputes.

And he answers the size question with a measurement rather than an opinion. Since he started putting insole lengths in every listing, the "too small" messages went from a regular annoyance to something he sees maybe once a quarter.

In Nairobi, Kevin runs the same trade at a different price point, selling ex-import sneakers at KSh 2,500 to KSh 4,500, mostly by WhatsApp with a rider doing cash on delivery across the city. His authentication problem is smaller because his buyers aren't paying for a label, and his reconciliation problem is much larger, because the money arrives as cash in a rider's pocket at the end of a long day of drops. That's a different article's territory, and it's rider handovers and cash reconciliation.

Returns, disputes and the policy you write before you need one

Write this once, in plain words, and put it on every listing.

Something like: returns accepted within 5 days of delivery if the shoes are unworn outside, in the original box, with all inserts. Buyer pays return shipping. Refund on receipt and inspection. No returns on pairs sold as beaters.

Three notes on that.

"Unworn outside" is the load-bearing phrase. Someone has to be able to try them on. Someone should not be able to wear them to a party and send them back with grit in the tread.

Buyer pays return shipping unless you got it wrong. If you shipped the wrong size or missed a flaw in the photos, you pay. Otherwise they do. Being clear about which is which keeps it from being a negotiation.

A chargeback is not a return. If you take card, the money lands in your own Stripe account, because Sailo never holds it, and a chargeback is then between you and Stripe. Nobody at Sailo can reverse it or argue it for you. That's the honest limitation of a setup where the money goes straight to you: you keep all the control and you also keep all the exposure. Your defence is the evidence pack, which is the ten listing photos, the packed box photo, the tracking number showing delivery, and the message thread. Have it in one folder per order. What to do about a chargeback covers how to put it together and what actually persuades.

While we're on the money: card payments need a Stripe account cleared for charges, and the commission is 1–3% of the goods on top of Stripe's own fee. On bank transfer, cash on delivery, WhatsApp, Instagram DM, Telegram, email or phone orders, Sailo takes nothing at all and never touches the money. At four pairs a week averaging $186, card volume is around $3,200 a month and the subscription is about 0.6% of it, which is easily worth it. At four pairs a month it isn't, and you should be taking transfers and meeting people in a supermarket car park like everyone else starting out.

Handling the actual return logistics without a warehouse, including what to do with a pair that comes back smelling of someone else's feet, is in handling returns without a warehouse.

Month six, when it goes wrong

A buyer sends a photo of a different pair. It happens. This is why you photograph the exact pair with an identifying mark visible, and why the box photo with the label matters. Compare the wear pattern on the outsole in their photo to yours.

"It's fake, I want a refund." Ask what specifically. Nine times in ten they've read one blog post about stitching counts. Send your receipt and the style code photos calmly. If they've had it authenticated by a service and it failed, refund immediately and go argue with whoever sold it to you.

A pair sits for four months. Cut it. Relist at a loss, sell it locally, or bundle it. The money tied up in slow stock is the most expensive thing in this business and it doesn't show up anywhere on a spreadsheet.

Someone asks you to ship overseas. Customs paperwork, longer transit, and a much harder dispute if it goes wrong. Do it only with tracked service, only after you've quoted the real cost, and never for a buyer with no history at a price that feels too easy.

The drop you queued for at 6am sells out and resells below retail. This happens more often than the stories suggest. Hyped releases are a lottery ticket, not a business model. Boring pairs in common sizes are the business model.

Someone offers to pay half now, half on delivery. For a stranger, no. For a repeat buyer, sometimes. If you do it, write both halves down and be specific about the date the second one lands, because a vague second half is how most of the money-chasing in resale starts.

What to do next

Take the pair sitting closest to you and photograph it in the ten shots, in order, on a plain surface with light coming from one side. Then pull the insole out and measure it. That listing, with a measurement and a dated purchase note in it, is the template for every pair you'll ever sell, and it's about twenty minutes to build once.

Write your returns policy tonight, in four sentences, and paste it into every listing. Writing it while nobody is angry is much easier than writing it while somebody is.

Then decide the two sizes you're going to specialise in and stop buying outside them for ninety days. Fast sales at a small margin beat a shelf full of interesting pairs you can't move.