How to verify a marketplace seller

To verify a marketplace seller, treat the application as a set of claims and check each one against evidence the seller did not write. Confirm that the person or business is real and consistent: the name, contact details and location agree with each other and with the seller's history, and a business appears in the registry where it says it was formed. Then find the seller's track record elsewhere, ask them to prove it is theirs, and check that the stock, prices and volume they want to list fit that history. Check again whenever the account changes, because an account that passed at onboarding can later change hands.

This piece takes the checks in the order an onboarding or risk team can run them, with a worked example and a short section for buyers asking whether a seller is legit. Our guides to linking related accounts and KYB verification go deeper on two of the steps.

Every seller application makes the same handful of claims, whether or not the form spells them out: who the seller is and where they are, whether they sell as a person or a business, what they sell and where they get it, and where they have sold before.

Marketplaces collect some of this directly. eBay's US seller registration page asks individual sellers for a full name, an address (it does not accept PO boxes) and a date of birth, among other details. A registered business gives its legal name "as it appears on your business registration documents", any trading name, and details for "anyone who is acting on behalf of your business". Other claims arrive as links, to the seller's profiles on other marketplaces, a social shop or their own website.

Verification means checking each claim against evidence the seller did not create: a registry record, contact details and profiles that predate the application, reviews other people wrote, and a brand's own list of who sells its goods. The application is where the claims come from, so it cannot also be the evidence for them.

The FBI's Internet Crime Complaint Center (IC3) received 56,478 complaints of non-payment or non-delivery in 2025, with reported losses of about $503 million. The category covers both sides of a sale: goods shipped and never paid for, and payment sent for goods that "are never received, or are of less quality".

In the BBB Institute for Marketplace Trust's 2025 Scam Tracker Risk Report, online purchase scams were the largest category, at 28.4 percent of all scams published on BBB Scam Tracker. Of the people who reported one, 89.3 percent said they lost money, with a median loss of $68, and toys and collectibles were mentioned 1,376 times in reports of online purchase and counterfeit scams. The figures come from reports people chose to submit, so they do not necessarily match how often scams happen.

The FTC reported in April 2026 that shopping scams were the most reported scam on social media in 2025. Most of the people who lost money after ordering something from an ad said they "paid for things that simply never arrived". On 7 August 2026, announcing a seizure of counterfeit goods at Houston's George Bush Intercontinental Airport, US Customs and Border Protection said that "Counterfeit versions of popular brands are regularly sold in online marketplaces and flea markets."

Start with consistency. The name, email address, phone number, address and location on the application should agree with each other and with the seller's history, and each should have existed before the application did.

Individual sellers

For a person selling under their own name, the evidence is mostly the age and spread of their contact details. An email address or phone number that appears in forum posts, old listings or a professional profile from years ago links to a real person more strongly than one created last week, though a US phone number that is given up eventually gets reassigned to someone else. Our guides to investigating an email address and investigating a phone number cover how to date each one and where to find it. Check, too, that the city on the application matches where the seller's other accounts say they are.

Business sellers

A business adds a registry record. Look it up in the registry where it says it was formed. In the US, most secretary of state offices register businesses, and their association, NASS, links to each state's business registration pages and name databases. Free searches vary: Delaware's entity search returns active and inactive entities alike and says a result "is not an indication of the current status of an entity". In the UK, Companies House lets anyone see some details for free, including a company's registered address, its date of incorporation and its current and resigned officers.

Then compare the record with the application: the legal name against any trading name, the formation date against the history the seller describes, and the people named in the filings against the people you are dealing with. A registry entry shows that a business was formed, and whether it trades is a separate question. A recently formed company can belong to an established seller turning a hobby into a business, and then the history should exist under the person's own name and handles.

A track record is the strongest evidence a new seller can bring, because other people built most of it over time. Look for it in four places.

• Other marketplaces. A seller profile shows when the account joined, what it sells and what buyers said, so read the feedback for the categories and prices the seller wants to sell in.
• A social shop. Instagram's About this account panel shows an account's "Date joined" and its "Former username count", the number of times the username has changed, though not the earlier names.
• The seller's own website. For a generic domain such as .com, the public registration record includes the date the domain was created, and ICANN's Lookup tool reads it through RDAP, which became the definitive source of that data in January 2025. Archived copies show what the site said over time, though the Internet Archive notes that some sites are missing because "the automated crawlers were unaware of their existence at the time of the crawl".
• Forums and reviews. A handle with years of confirmed trades in a collectors' forum is hard to fake. The FTC's advice to shoppers works for an onboarding team too: search the name with the words complaint or scam, read reviews from several sources, consider "the reviewer's history", and do not rely on star ratings alone, "because some reviews and ratings are fake or misleading".

A history only counts if it belongs to the applicant, so ask them to prove control of each profile they name. One way is to send a short code and ask them to add it to the profile's description, or to message you from the account.

Compare what the seller wants to list with what they have sold before. A history of selling used video games does not cover two hundred new consoles. These patterns deserve a closer look:

• A new account listing scarce, high-demand items below the going price. The BBB's advice to shoppers warns that "Scammers offer hard-to-find products at great prices".
• A sudden move into a new category, especially one that is more valuable, more often counterfeited or harder to source.
• A jump in volume, or a steady supply of new retail goods from a seller with no supplier behind them.

The last pattern is one way stolen goods reach marketplaces. In a case the Justice Department described on 29 July 2026, a resale business that ran stores on two large online marketplaces bought goods it knew had been stolen from area retailers, mainly over-the-counter medications and health and beauty products, "far below the retail price". In many instances the goods "still had anti-theft devices attached", or stickers marking them for sale only at a particular retailer, and prosecutors wrote that a retailer had complained one of the stores "was not authorized to sell their products".

When the stock does not fit, ask where it came from. Ask a seller who buys from a distributor or wholesaler for an invoice, and a collector selling off a collection for a photo of it with their username and the date.

Some sellers claim to be a brand's authorised reseller, official retailer or distributor. Where the brand publishes a list of authorised dealers or a store locator, check the claim against it, using the current copy. Nikon Inc., for example, publishes a dated list of its authorised US dealers and notes that it "is subject to change at any time". Where there is no list, ask the brand.

A seller missing from the list may still sell genuine goods bought at retail or second hand, so the list tests only the claim of authorisation. A seller who says they are authorised and is not on the brand's own list has made a statement that does not hold, and the rest of the application deserves the same scrutiny.

Compare what the new seller shares with accounts already on your platform, especially ones you have closed. Contact details, return addresses, product photos and listing text can all travel between accounts run by the same operator.

Two searches cost little. Google's search by image can return "Websites with the image or a similar image", which finds photos taken from another seller or a brand. A distinctive sentence from the listing, searched as an exact phrase inside quotes, finds the same text elsewhere. Check the dates: when two listings share a photo, the older one is more likely to be the source. Our guide to linking related accounts covers how much each shared detail is worth, and why a value shared by thousands of accounts proves little.

A verification describes the account on the day it was checked. eBay's registration page says it may need to verify a seller's details "when you register for a seller account, or if you update any relevant information on your account". Changes that justify a fresh look include:

• New contact details, especially an email address and phone number changed together, or shortly before a change of payout details.
• A new location or shipping origin.
• A sudden change of category or volume, or an old, quiet account that wakes up with high-value listings.
• A new name or handle, or a profile elsewhere that has been renamed.

Social media accounts with a history are bought and sold, which matters when a social shop is part of a seller's track record. In a study presented at the 2025 ACM Internet Measurement Conference, researchers at CISPA and Saarland University found 38,253 accounts listed for sale on 11 online marketplaces between February and June 2024, across X, Instagram, Facebook, TikTok and YouTube, at a median price of $157. Such accounts, they wrote, "often come with out-of-the-box public metrics such as followers, likes, and interactions". A takeover looks similar: the history is real, and someone else now controls it. Re-run the checks on whatever changed, and confirm the change through a contact detail you already hold.

The buyer's version of these checks is shorter.

• Look at how long the seller has been on the marketplace, what they have sold before and what buyers said, and search their name with the words complaint or scam, as the FTC suggests.
• Treat a brand-name item at a low price as a question. The FTC warns that "If expensive brand-name items are offered for bargain prices, they could be counterfeit or stolen."
• Pay through the marketplace's checkout and, where you can, by credit card. The FTC says never to buy from online sellers "that insist you can only pay with gift cards", wire transfers, payment apps or cryptocurrency.

If a purchase goes wrong, tell the marketplace. In the US, report it to the FTC and file a complaint with the IC3.

The case is a composite. Sarrowden Cards and Theo Sarrowden are invented, the domain uses the .example ending reserved for documentation, and the phone number comes from the 555-0100 to 555-0199 range reserved for fictional use.

A collectibles marketplace receives a business seller application from Sarrowden Cards LLC. The contact is Theo Sarrowden, at theo@sarrowdencards.example and +1 330 555 0164. The application says Theo has sold trading cards for six years under the handle sarrowdencards on a large general marketplace, and describes the company as an authorised distributor for a card publisher. The first listing is 60 sealed booster boxes of a set released ten days earlier, priced about 25 percent below what the same boxes sell for elsewhere, plus 40 graded single cards.

The registry. Sarrowden Cards LLC was formed in its home state seven weeks before the application, and Theo's name is on the formation filing. For a new company, the history should exist under Theo's own name and handle.

The contact details. sarrowdencards.example was registered eight weeks ago, which fits the new company. The phone number appears in Theo's trade posts on a collectors' forum going back to 2021, under the same handle.

The track record. The sarrowdencards profile joined in 2020 and has about 1,900 feedback ratings, nearly all for single cards under $50, at around 30 sales a month, with no disputes in the past year. The team sends Theo a short code and asks him to add it to the profile's description. He does within the hour, so he controls it today, and the forum posts with the same handle and phone number since 2021 suggest it has been his throughout.

The stock. Sixty sealed boxes of a new set is a different business from 30 singles a month. Asked where they came from, Theo says he bought an allocation from a distributor at wholesale, which could explain the price if an invoice shows it.

The authorisation. The publisher's own list of authorised distributors does not include Sarrowden Cards. Theo says he buys from a listed distributor and is not one himself, and he changes the wording on his listing.

The photos. Most are the publisher's promotional images, which honest sellers use too. One photo of boxes stacked on a desk also appears in a listing from another account on the same marketplace, closed last month after buyers reported orders that never arrived. Theo had posted the photo on the forum a week before that listing went up, so the closed account most likely copied it from him, and it shares nothing else with Sarrowden Cards.

The decision. The team approves Sarrowden Cards as a business with a listing cap. The graded singles go live, since they continue Theo's history. Sealed product is capped at ten boxes until Theo sends the distributor's invoice and a photo of the stock with his username and the date written on a sheet of paper. Two questions stay open, and the file says so: where the full allocation came from, until the invoice arrives, and whether the closed account had any connection beyond a copied photo. The team flags the account for another review the first time its contact details, category or volume change.

Count only independent evidence: a website and a social profile that both repeat what the application says are the seller's own words seen twice.

Each check has a known way around it.

• A bought or taken-over history. Proof of control passes, because whoever holds the account now controls it. Look for change around the time it may have changed hands: a rename, a new location, a gap in activity or a new category.
• A borrowed identity. Someone can apply with a real person's name and details. Proof of control of the profiles they name, and contact through details that predate the application, are the checks most likely to catch it.
• Fake reviews. The FTC warns that some reviews and ratings are fake. Years of feedback from buyers with histories of their own are harder to fake than a burst of five-star ratings.
• A slow build. A seller can trade honestly at low volume for months and then list high-value stock it never ships. The onboarding checks pass, which is why a jump in value or volume should start a fresh look.
• Copied stock photos. A photo of someone else's stock passes an image search if the original was never posted. A photo with the seller's username and the date in the frame is harder to copy.

These checks raise the cost of a fake seller without making one impossible. The ones that hold up best rest on records other people built over time.

Most of what makes a seller application look odd has an ordinary explanation, and a fair review checks it first.

• Every seller is new once. A first-time seller has no track record, so ask for different evidence: a photo of the stock, receipts for it, and a listing cap that rises with good sales.
• Collectors sell their collections, and a large lot of sealed product from someone who has only sold singles can be exactly that.
• A seller missing from a brand's authorised list may still sell genuine goods. Only a claim of authorisation fails that check.
• Honest sellers use the same promotional photos and the same product descriptions, so a shared image counts only when it is supposed to be the seller's own.
• People move and change email addresses and phone numbers, and old numbers are reassigned. A change the seller can explain is ordinary.
• Some people keep a thin footprint for privacy, or sell mostly in person at shows.

So keep three levels apart. Thin means look further. A contradiction, such as a profile the applicant cannot control or an authorisation the brand does not list, calls for an explanation. A current record you found yourself, such as the brand's own list, carries the most weight. Ask the seller about anything that does not fit before deciding.

Checking a seller's history by hand means working through other marketplaces, social profiles, forums and registry filings, and noting the source of every finding. Sixtyfour's agent starts from what the seller gave you, such as a name, an email address, a phone number, a username or a business name, researches public sources, and links what it finds to the right person or business. Every finding comes with its source, and anything it could not establish is reported as open. A person on your team decides. It does not check bank accounts or payout details. There is more on how platform teams use it on our trust and safety page.

Treat a seller application as a set of claims and check each one against evidence the seller did not write: the registry for a business, the age of the contact details, a track record the seller can prove is theirs, stock that fits that history and the brand's own list for any authorisation. Check again whenever the account changes.