Nowhere to go: what the big marketplaces ask of a private seller, and what CoArt Market asks

A market for those who are already inside

Today, in effect, these people have nowhere to go. Artists show their art on Instagram, Threads and X, and sell it there too, with no protection at all. There is no proper agreement, and no certainty that the money will arrive or that the object will be the one shown. Both sides take the risk. For an elderly collector, it is hard even to see how to sell something online on their own.

In principle, a marketplace exists for everyone who has something to sell and everyone who wants to buy. In practice, as I see it, the market is controlled by a few large platforms, and the rules are theirs. It closely resembles the oligopoly that has formed in the blue-chip art market, which Michael Shnayerson described very precisely a few years ago in his book "Boom: Mad Money, Mega Dealers, and the Rise of Contemporary Art". Whoever wants to sell accepts their terms. Whoever does not remains at the door.

One might say that this is simply how all large companies work. But these rules decide who reaches the market at all. Artists write to us. So do heirs who do not know what to do with things left by relatives, and people who found something in an abandoned house. Often they have nowhere to turn, even to understand what they are holding. Experts are not found in every town, an expert opinion costs money, and it is not even clear whom to ask. And so a great many cultural artefacts simply fall out of cultural circulation.

To illustrate these points, I decided to walk this road myself. On 24 and 25 October, from my own accounts, I tried to sell something as a private person on four marketplaces. Below is what I saw, quoted from their own pages.

Catawiki: easy to buy, much harder to sell

Buying on Catawiki is very easy: an account, an address, a phone number, and a letter arrives under the subject "You're in Dimitri! Bid from €1". But I had come to sell.

I chose "Privately", which Catawiki explains as "Not related to your trade, business, craft, or profession". Even before the first object, I was sent to its payment partner: "Our payment partner Payoneer needs to check some identity documents before you can receive payments". Proof of identity and of address were asked for.

Payoneer then asked for "your business email address" and "Where is your business registered?". It asked "Which industry or trade best describes your business?", in one long list from restaurants to tobacco wholesale and agriculture. Then: "Around how many transactions do you usually make every month?" When I answered "None yet, this is a new business", the session dropped and everything started again from the beginning. I never managed to list my first object.

I have considerable experience in online commerce, and even I found this road hard. Now imagine an elderly collector who wants to sell a painting from their collection. They do not see themselves in tobacco or in agriculture. For them, this door is closed.

I should add that a seller's identity must be checked, and EU law requires it where money changes hands. And Catawiki's object pages are good: the one I read names the expert who selected the object. So where is the question? Not in whether to check, but in when and how.

1stDibs: for professionals only

1stDibs offers two doors: "I'm a professional seller or gallery" and "I'm an individual looking to sell a few items". The second answers at once: "At this time, our platform is exclusively open to professional sellers and galleries for selling merchandise." No private sellers.

It is a consistent position, and it is their model. The page says they select "only prestigious sellers and galleries", and speaks of "more than 7,600+ of the world's best sellers and galleries from over 50 countries". What is remarkable is something else. My account there is an old one: in 2025, as a buyer, I wrote to a seller there. I may buy. I may not sell.

Saatchi Art: an application first

Saatchi Art is a marketplace for artists. Before offering anything, an artist fills in an application of nine steps: education, exhibitions, income from art. Then comes "Upload 3 artworks for our team to review, along with each artwork's category and price (in USD)." It warns: "Failure to provide an image of listing quality may result in a rejected application". The answer is promised "within 2 business days".

My answers were those of an emerging artist: no formal training, no exhibitions, nothing sold. Is that reason enough to keep an artist away from buyers? I am convinced it is not. Nobody knows who will be the next Basquiat.

And for an heir who happens to hold a painting by someone else's hand, this marketplace is not meant at all.

eBay: the simplest road

In fairness, eBay's road is the simplest of the four. A country, an address, then one box: what are you selling? The platform chose the category itself from my words. The details are picked with buttons: there are 32 of them for paintings, and none is required. So a light form is possible.

But eBay is built to sell quickly, not to certify. Authenticity there is one question, "Certificate of Authenticity (COA)", yes or no. All a buyer learns of the object's history is what the seller writes.

Hence the main question. Can a form be as light as eBay's and still give the object a certificate that passes to every next owner? I am convinced it can.

What we ask

My partners and I have kept one measure for many years: for the seller, as convenient and clear as possible; for the buyer, simple and safe at the same time. In practice, it looks like this.

• An account: a simple e-mail verification, and your consent to a blockchain account being created automatically for every user, at the level of our underlying platform, FracTown.
• The Seller Declaration, once, at your first upload: your name as in your document, your date of birth, and confirmation that you sell your own object as a private person. Your name and date of birth are never shown publicly.
• For each object: 5 to 15 photographs, its documents if there are any (a phone photograph of a document will do), and your story: where the object came from and whose it has been.
• Fingerprint: close-ups of particular places on the object's surface and other data to identify it. What we ask depends on what you sell: a painting, a watch, a coin or a piece of jewelry. Each family of objects has its own method; where there is none yet, one is being prepared.
• A preliminary assessment: within a few days, CoArt Market's expert group assesses whether the object has artistic and collectible value, and writes to you. Then the object receives its own cryptographic certificate, and you set the price.

Why all of this

The object's certificate, the FCC, is a cryptographic certificate. It is recorded on the Symbol blockchain and bound to the object's "information container" in Arweave, a decentralized storage where nothing written can be changed or deleted. The certificate keeps the history of ownership and the data by which the object can be identified precisely in the future, should that ever be needed.

Where an object has a digital fingerprint, its close-ups are stored encrypted. The buyer receives access to them only after delivery. Then they can compare what they photograph of the object in their hands with what is recorded in the storage, and be sure it is the very same object.

The comparison is made by a computer-vision program. In the buyer's photograph and in the close-up from the certificate it finds the keypoints of the surface and their SIFT descriptors. It keeps only the pairs that agree with one geometric model, a homography estimated by the MAGSAC method. In other words, the program checks whether the finest texture of the surface matches.

Unique physical objects are bought as is (caveat emptor). So after delivery there can be one claim: the object delivered is not the one shown. A CoArt Market specialist decides it, on what the program found.

Each change of owner on CoArt Market is also recorded with the date and the price of the sale, without the parties' legal names or contact details. So any future buyer sees the history of ownership and the real prices at which the object was sold and bought. The sale itself is made by a sale agreement that both parties sign electronically.

The FCC and the record of the transfer of ownership in the provenance ledger do not prevail legally over that agreement. But they confirm, in a way that is easy to check on request, that this is the very object, and they keep its identification data encrypted, so that, if and when it is ever needed, this can always be confirmed.

What we do not ask

We do not ask which industry you work in or whether your business is registered. An object is uploaded, receives its preliminary assessment and is put up for sale without bureaucratic procedures. Identity is checked where the money is: the payment provider, Stripe, checks it, as EU law requires.

Money, briefly

Our fee is 10%, and only on a completed sale. While we build our first network in Europe, listing an object and its certificate cost nothing. The seller and the buyer agree on the price and any discount between themselves: the seller can change the price in a few clicks to meet the buyer halfway. Our task is to process the payment, keep our fee and see the sale through so that it is safe for both sides.

Whoever buys can sell

On NFT marketplaces there was never any difference between a buyer and a seller: whoever bought could resell at once. We took that idea and brought it to physical objects.

Having bought an object on CoArt Market, you can sell it here too, from your own showroom, on the same terms. The certificate passes with the object, and no new review is needed. Buyers and sellers have equal rights here. Every buyer is also a seller, even if they are not selling anything yet. Not everyone buys to resell. But everyone may. That is our main difference from marketplaces that decide who may sell.

For heirs and finders: what we are developing

Today, every object is reviewed before its certificate by CoArt Market's expert group: myself, and the experts and advisers I work with. It does not examine authenticity. It gives a preliminary assessment of whether the object has artistic and collectible value. That assessment does not confirm authenticity and sets no price. The seller answers for the evidence of authenticity. Obvious fakes are not admitted.

Why this assessment, then? To offer everyone who takes part quality objects with a clear preliminary attestation, above all objects that spent many years out of cultural circulation.

To automate this work and take in far more submissions, including from the most remote corners of the world, we are developing DAC (Decentralized Art Consulting), a decentralized community of experts. Several experts who do not know one another each give their opinion, and an algorithm finds the median. It is not a confirmation of authenticity but an attestation, and a road to the world market.

Why we are not competing with them

I do not see these marketplaces as competitors, and not out of modesty. They have grown large and slow, and they serve those they chose to serve. We address those who were left at the door.

Convenience for the seller and for the buyer: that, I believe, is where we will move ahead. The market of art and collectibles should be open to everyone who has something of value, not only to those who have a business.