Purpose-Built for UK Watch Dealers
Inventory management software for pre-owned and vintage watch dealers. Track movement, case material, reference and serial numbers, service history, and margins on every piece. Manage your stock across Shopify, marketplaces, and in-person at fairs from one place. Built by someone who has run the back office of a UK dealing business since 2013.
Inventory
6 items
Art Deco Diamond Ring
JWL-2026-0089
Cartier Tank Watch
WCH-2026-0034
Georgian Silver Candelabra
ANT-2026-0056
Hermès Birkin 25
HBG-2026-0012
Edwardian Sapphire Pendant
JWL-2026-0091
Rolex Datejust 1601
WCH-2026-0035
Watch dealing runs on detail: reference, serial, calibre, service dates, box and papers. Lose one of them and the piece is harder to price and harder to sell. GemJam gives each detail its own field on the watch's record.
A vintage Rolex Submariner needs reference number, serial, movement calibre, dial variant, and service history. A modern Omega needs box and papers status. A pocket watch needs case material and movement details. Force all three down the same fixed set of columns and the detail either lands in a description box or never gets recorded.
Buyers of pre-owned and vintage watches expect transparency about authenticity, service history, and prior ownership. Without a system that links every piece to its documentation, signals, and chain of ownership, answering provenance questions becomes a paper trail of guesswork.
Buy a watch you were not charged VAT on, such as one from a collector or a private seller, and it can go through the Margin Scheme if it is goods the scheme covers. You still have to establish which watches actually qualify, apply 1/6 to each margin, and keep records that hold up when HMRC asks to see them.
Watch dealers list on Shopify, on marketplaces like Chrono24 or Watchfinder, and sell in person at watch fairs and shows. Keeping stock accurate across every channel when each watch is unique means constant manual updates and the risk of selling something twice.
Taken in the order a watch moves: onto the books, through the workshop, out to a buyer.
Build templates with the fields that matter — movement type, case material, case size, bracelet or strap material, reference number, serial number, service history, and papers/box completeness. A vintage watch template can differ from a modern one. You decide what to track.
The seller's VAT status is captured alongside the purchase, and the margin VAT is worked out the moment the watch sells. A return that used to mean an evening with a calculator becomes a report you open and check.
Publish a watch to Shopify from inside GemJam. Record the sale and your stock moves in step with the connected Shopify listing. Any channel outside that link you keep in step yourself. eBay integration is in development. Marketplace bridging tools for sites such as Chrono24, Watchfinder, and Bezel are on the roadmap as future integrations — bulk-export listings without retyping every reference.
Log every service against the watch record — date, watchmaker, work carried out, parts replaced, and cost. When you come to sell, the full service history travels with the piece and directly supports the price you can achieve.
PUR-2026-0042
Hatton Garden Estates · 15 Feb 2026
Subtotal
£8,250.00
VAT
£0.00
Margin Scheme
Total
£8,250.00
Line Items
Art Deco Diamond Ring, c.1925
JWL-2026-0089
£3,450.00
AvailableVictorian Pearl Brooch
JWL-2026-0090
£1,800.00
SoldCartier Tank Watch, 1970s
WCH-2026-0034
£3,000.00
AvailableA vintage Rolex one week, a modern Grand Seiko the next, a tray of pocket watches at the following fair. Set up a template per category and the form in front of you only asks for the fields that watch actually has.
Track movement type (automatic, quartz, manual), calibre, jewels, complications, and beat rate. Filter your stock by movement when a customer wants something specific, or pull a report of every chronograph in inventory.
Capture case material (steel, gold, platinum, titanium), case size and thickness, dial colour and signature, bracelet or strap material, and bezel type. Calculated fields can mask serial numbers on public listings while keeping the full number in your records.
Record reference number, serial number, year of manufacture, and the completeness of the set — box, papers, certificate, service records, hangtags, and any third-party authentication reports. Buyers of high-value watches expect this level of documentation.
Every watch links to its purchase record and the contact you bought from. Track where each piece came from, what you paid, prior ownership, and any auction or estate history — giving buyers the provenance details they expect when paying serious money.
A pre-owned watch you were not charged VAT on, such as one bought from a collector or a private seller, can go on the Margin Scheme if you choose to use it. Precious metals, investment gold and precious stones cannot go on the scheme. The scheme charges VAT on the profit margin rather than the full selling price. GemJam keeps the stock book records as you buy and sell; whether a watch qualifies still depends on the watch, how you bought it and meeting the scheme's conditions, and you keep your purchase and sales invoices alongside.
A VAT treatment recorded for every watch you buy, with unclear cases flagged for your review
VAT worked out at 1/6 (16.67%) of the margin on each eligible watch
Produces the Stock Book and invoices from the same records
Xero-compatible export, ready to pass to Dext
Everything listed is in GemJam now, except items marked coming soon.
Straight answers on fields, authentication, service history, and VAT.
GemJam lets you build custom item templates with the fields that matter for watches — movement type (automatic, quartz, manual), case material, case size, bracelet or strap material, reference number, serial number, service history, and papers/box completeness. A vintage Rolex template can look different from a modern Omega template, and each captures exactly the detail your stock and your buyers expect.
GemJam does not authenticate watches for you — that judgement is yours. What it does do is give you the structure to record every signal your buyers ask for: reference number, serial number, movement details, dial signature, case markings, service history, and links to original papers, certificates, or third-party authentication reports. Every record is searchable, so you can answer provenance questions in seconds rather than rummaging through files.
The Margin Scheme is optional: you can choose to use it for pre-owned watches, including those bought from private sellers or from other dealers selling under the scheme. The eligibility judgement stays with you, on the watch and on how you acquired it rather than on the seller. Buying from a private individual or a non-VAT-registered seller usually means no VAT was charged, but the watch still has to be second-hand stock the scheme covers, and the purchase has to be one on which you were not charged VAT, or one a dealer sold to you under the margin scheme. Precious metals, investment gold and precious stones cannot go on the scheme. When a scheme watch sells, GemJam works VAT out at 1/6 of the profit margin rather than the full selling price, and produces the Stock Book and invoices from the same records.
Yes. GemJam pushes your listings to Shopify and updates inventory across channels when a watch sells. eBay integration is in development. Marketplace bridging tools for sites like Chrono24, Watchfinder, and Bezel are on our roadmap as future integrations — today you would export listings or copy details manually. For in-person sales at watch fairs, you record the sale on your phone and your inventory updates everywhere instantly.
Yes. Each watch has its own record, so you can log every service — date, watchmaker, work carried out, parts replaced, and cost. When you come to sell, the full service history travels with the item. Buyers of high-value watches expect this transparency, and it directly affects the price you can achieve.
A watch is a serial number with a history attached, and no two records look quite the same. GemJam treats every watch as unique, with its own purchase price, reference and serial number, movement details, condition, and margin. It handles VAT Margin Scheme calculations natively, pushes listings to Shopify (eBay coming soon), and produces the Stock Book and invoices from the same records. It was built by someone who has run the back office of a UK dealing business since 2013 and understands the specific challenges of trading in unique pieces.
Sell more than watches? Jewellery, antiques, and designer handbags can all sit in the same system.
Reference, serial, calibre, service history, and margin held on the watch's own record and ready when a buyer asks. Join the waiting list for early access.