Genmars Business Platform
Custom software · Retail & multi-branch operations · 2026
A multi-tenant point of sale and back office: one deployment serving many independent businesses, each seeing only its own branches, stock and takings.
A till that scans, prices and takes payment; branches and registers with a shift and a drawer to reconcile; a catalogue where a shelf price carries its own VAT rule; stock that only moves with a reason attached; and sales, refunds and reports on the other side of the counter. Cashiers sign in at the register with credentials that belong to the business employing them and never reach Genmars.
- Multi-tenant isolation
- Point of sale
- VAT-inclusive pricing
- Stock with an audit trail
How it is built
Django and DRF behind one Caddy host that splits by path, with a Next.js application for the back office and a browser-held session for the till. Tenant isolation lives in a single module rather than in each view, and a read that falls outside a caller's scope answers 404 rather than 403 — a 403 confirms the row exists, which is an enumeration oracle in a different costume.
Two tiers of identity that never cross: subscribers authenticate through a Genmars account, while a shop's own cashiers hold tenant-local credentials that cannot authenticate anywhere else. Checkout carries an idempotency key, so a retried sale returns the original rather than charging twice. Transaction history is immutable — a cancellation marks the sale cancelled and a refund is written beside it, so what was charged stays what was charged.