Case study · Consumer marketplace · graded LEGO® sets
Set Trader.
The UK marketplace for complete LEGO® sets: every set graded from sealed to sold as seen, the buyer’s money held until they have checked it, and prices taken from real UK sales.
Live at settrader.co.uk · built and run by T19 Digital
The problem
Buying a second-hand set on a general marketplace is a gamble. Listings say “complete, I think”, nobody has counted the pieces, prices are guesswork, and the money has gone before the box is opened. Sellers have the opposite problem: no way to prove a set is complete, and buyers who haggle because they can’t trust it.
What we built
- Six grades, each with a checklist the seller confirms before they can list: sealed, complete with box, complete without box, complete without instructions, incomplete with every missing part listed, and sold as seen
- Payments held by the platform through Stripe Connect: the seller posts with tracking or hands over in person with a one-time code, the buyer has three days to check, and the seller is paid only then. Missing pieces on a complete grade are replaced up to £15
- A free collection tracker: scan a barcode or snap a photo and the AI identifies the set, then values the collection from completed sales, with alerts when a wanted set is listed, gets cheaper, launches or is about to retire
- A price guide by set and grade from what actually sold, offers (on listings and on sets in other members’ public collections), and pay links for a sale agreed in a Facebook group or at a fair
- Fees capped at £15 each way and shown up front: a 4% buyer guarantee included in every price, and a 3% seller fee (1% for £49-a-year Collector members)
- A 16+ community with groups, LEGO news, UK events and an assistant that answers with live prices, with every post and photo screened automatically
Under the bonnet, in plain English
The hard part is the money. The platform takes the payment, holds it through posting, collection and the three days of checking, and only then moves it to the seller, with refunds, part-refunds and late-dispatch rules running on an hourly schedule nobody has to remember. Under that is a catalogue of every set refreshed nightly from two public databases, and the paperwork a UK marketplace needs before it takes a penny: a data protection impact assessment, an Online Safety Act risk assessment and prices that obey the new rules against hidden fees.
LEGO® is a trademark of the LEGO Group, which does not sponsor, authorise or endorse Set Trader.
What this proves for your project
If your business needs other people to trade, book or pay through it (a marketplace, a hire platform, a members’ exchange), this is the proof we can build the trust layer: payments held and released on rules, disputes handled, and compliance done properly rather than left for later.
Want yours to work like this?
Same builder, same standards, your business.