A trading card marketplace is a trust business with a payments problem attached. To start one in 2026 you choose a model (peer-to-peer listings, consignment, or live selling), build the listing and payment stack on a connect-style processor, meet the seller verification rules that now carry fines (the INFORM Consumers Act in the US, DSA Article 30 in the EU), verify sellers with identity and one-to-many face dedupe so bans stick, screen listings for fake cards and cloned slabs, and price a take rate the market accepts. The companies that did this recently raised real money: CardNexus closed a €3.5 million pre-seed in June 2026 three months after its marketplace went live.

This guide covers the decisions in order, with the regulation and the fraud data that shape them. Marketplace verification is the deepidv vertical behind it. It pairs with TCG marketplace fraud in 2026 for the scam patterns and marketplace fraud, INFORM and the DSA for the legal detail.

Which marketplace model should you pick?

Three models, each with a different trust problem.

• Peer-to-peer listings (TCGplayer, CardNexus). Sellers list, buyers buy, you hold the payment. Your risk is the seller: fakes, non-delivery, ban evasion. eBay paid $295 million for TCGplayer in 2022, which tells you the model works at scale.
• Consignment and auctions (Rare Candy). You take custody, authenticate, and sell. Your risk moves to your own intake and your own custody. Rare Candy is venture-backed by Lerer Hippeau, whose investment note says buying collectibles "frequently involves fraud, misinformation, and poor customer experience".
• Live selling (Whatnot). Sellers stream, buyers bid in real time. Your risk is seller quality at volume; Whatnot's iPhone app lets sellers scan a PSA or CGC slab to import listing details, which is where a cloned cert enters.

Pick the model your first hundred sellers already use. A collector community that trades in Discord wants peer-to-peer. A dealer network wants consignment. Streamers want live.

What does the stack look like?

• Listings. A card catalog with images, set and collector numbers, condition, and for graded cards the cert. The scanner is the on-ramp: CardNexus recognizes a card in under 100 milliseconds, offline, and turns the scan into a pre-filled listing.
• Payments. A connect-style processor that holds funds and pays out sellers, with escrow until delivery confirmation. Card marketplaces are not restricted businesses; gambling-style mystery products can be, so check the processor's list before adding repacks.
• Seller onboarding. Identity, one-to-many face dedupe, payout account in the seller's name. Detail below, and the vibe-coded marketplace guide shows how to build the onboarding flow with a vibe-coding tool.
• Listing screening. Photo-based authenticity check on listings above a value threshold; cert-to-image match for graded cards.
• Disputes and shipping. Tracked, insured shipping with declared value; a dispute flow that references the proof of what was verified.
• The app. Most volume is mobile. The scanner apps collectors already use are covered in the TCG scanner app landscape.

What does the law require of a card marketplace?

Two regimes, and both now come with enforcement.

United States: the INFORM Consumers Act. Any marketplace with a high-volume third-party seller, meaning 200 or more transactions and $5,000 or more in gross revenue in a 12-month period, must collect and verify that seller's bank account, government ID, tax ID and contact information within 10 days, recertify annually, disclose sellers above $20,000 in revenue on the listing, and give consumers a reporting mechanism. A weekend card flipper crosses 200 transactions in a season. The FTC's first case under the Act settled with Temu for $2 million in September 2025, and the allegations included a missing telephonic reporting mechanism and missing disclosures in mobile listings.

European Union: DSA Article 30. Before a trader can sell, the platform must obtain name, address, phone and email, an ID document copy, payment account details, trade register details and a self-certification, make best efforts to verify them, suspend non-compliant traders, and keep the data six months after the relationship ends. The Commission fined AliExpress €550 million in July 2026 and Temu €200 million in May for failing to manage illegal and counterfeit goods risk.

A card marketplace with sellers in both regions needs one onboarding flow that satisfies both. That is cheaper than it sounds, because both regimes are asking for the same thing: a verified identity tied to a verified payout account.

How do you verify sellers so bans actually stick?

Four controls, all available as API calls.

1. Identity at onboarding. Document plus face liveness plus match. With deepidv, a workflow with ID_VERIFICATION and FACE_LIVENESS steps and a hosted session: POST /v1/sessions returns a session_url, the seller completes it on their phone, and your webhook receives session.status.verified (docs). Under a minute for most sellers.
2. One-to-many dedupe. A banned seller returns with a new email and phone, never a new face. deepidv's 1:N check returns UNIQUE, DUPLICATE or SELF_EXCLUSION for a face against your enrolled base (reference); run it on every enrollment.
3. Payout account verification. The account that receives money belongs to the verified identity. deepidv's bank statement request and financial checks cover this; PEP and sanctions screening (POST /v1/screening/pep-sanctions) is a cheap add-on once identity is verified.
4. Step-up on risk. New payout account, new device, listing pattern that breaks from history: re-run liveness before the change goes live. Account takeover of trusted sellers is the growth fraud of 2026.

Every check is sealed as a proof at proof.deepidv.com with no personal data on chain, which is what you hand a regulator when they ask whether you verified.

How do you keep fake cards off the marketplace?

The seven scams are documented in the fraud guide. Three controls cover most of them:

• Authenticity screening at listing. A photo-based check on listings above a threshold, before they go live. PSA intercepted $200 million of counterfeit and altered collectibles in 2025, with TCG at 56.3 percent of it; most of those were headed for a marketplace.
• Cert-to-image match for slabs. A real cert number on a fake holder passes a QR scan. Matching the listing image to the grader's record image does not.
• Grade estimate versus label. A gap of more than a point between the estimate and the label grade flags the listing for review.

deepidv's TCG Authenticity Verification runs the first and third from the listing photos and returns a proof; partner access via cal.com/team/deepidv.

What should the take rate be, and what does it cost to run?

Take rates in collectibles cluster around the low double digits for peer-to-peer and higher for consignment and live selling where the platform does more work. Your costs are payments (processor fees), verification (per seller at onboarding and per listing screened), disputes and support, and shipping insurance where you offer it.

Verification is the line founders overestimate. Seller identity is a one-time cost per seller at the public list price, a repeat check on an already-verified person is $0.05, and listing screening is priced per check from $0.05. On a $50 average order at a 10 percent take, one screened listing costs a fraction of the fee it protects.

How did the recent entrants do it?

• CardNexus (Bordeaux): marketplace live March 2026, 50,000 users, 30 million cards inventoried, 10 million scanned, sellers in 30 countries, and a €3.5 million pre-seed led by Piton Capital announced 11 June 2026, with a physical vault planned for 2027. The scanner is the acquisition channel; the marketplace monetizes it.
• Rare Candy (New York): consignment and auctions plus a scanner app that identifies raw and graded cards, including PSA, CGC, BGS, SGC and TAG slabs. Founded by a Pokemon creator with an audience, which is the licensing lesson from the Kickstarter TCGs applied to a marketplace.
• TCGplayer (eBay): the incumbent, with a scanner whose own reviews complain about accuracy. Accuracy and trust are the openings.

Frequently asked questions

Do I need to verify sellers on a small card marketplace?

Yes, once any seller crosses 200 transactions and $5,000 in a year under the INFORM Consumers Act, and for every EU trader under DSA Article 30. Verification also stops the fraud that kills small marketplaces first: ban evasion and fake cards.

What is the cheapest way to verify sellers?

A hosted verification session from an API: the seller completes it on their phone, you receive a webhook. deepidv sessions are a single call and repeat checks on already-verified people cost $0.05.

How do card marketplaces stop fake cards?

Photo-based authenticity screening on listings above a value threshold, cert-to-image matching for graded cards, and a grade estimate compared to the label. Sellers who are verified and deduplicated cannot relist under a new name when caught.

What take rate do card marketplaces charge?

Low double digits for peer-to-peer listings; higher for consignment and live selling where the platform handles custody or streaming.

Should I build a scanner app or a marketplace first?

Recent entrants built the scanner first as the acquisition channel and added the marketplace once users were scanning daily. CardNexus is the current example.

How do I prove to a regulator that I verified a seller?

Keep a tamper-evident record of each check. deepidv seals every verification as a proof at proof.deepidv.com with no personal data on chain.