Live Auction Marketplace

Live auction commerce is one of the harder e-commerce categories to build correctly. The product has to keep video, chat, and bidding honest at once while guaranteeing that money-critical events are never ambiguous: two people tapping Buy Now in the same instant must produce exactly one order, a bid arriving in the last second must extend the auction fairly, a video glitch must never corrupt auction state, and every bid must remain provable after the fact.

The two-region launch added a second layer of difficulty. The UAE and Australia differ in currency, tax (VAT versus GST), consumer law, and even in what Stripe offers, Express accounts are unavailable in the UAE, forcing a Custom-account integration with platform-hosted compliance. Region had to be a first-class concept in payments, tax, sale terms, and seller onboarding, not a translation detail.

Postgres is the system of record and Redis is a derived cache: the bid write path never reads Redis, and a full Redis flush loses no business data. Video and bidding ride separate transports, LiveKit WebRTC carries video while Socket.IO and Postgres carry bids and chat, so a video hiccup cannot corrupt an auction.

The server is authoritative for everything with money in it. Auction timers are absolute server end-times; prices, currency, commission, and tax are computed server-side; no money value is ever accepted from a client. The mobile checkout sends product IDs and an idempotency key, nothing else.

Platform economics are configuration, not constants. Commission rates, tax rates, bid increments, anti-snipe windows, and dispute-hold periods live as settings rows with per-seller, per-category, and default precedence, editable from the admin panel.

A dedicated auction module implements bid validation, increment bands, reserve prices, and anti-snipe extension, with exactly one code path allowed to write a bid and exactly one component, the background worker's close ticker, allowed to close a lot. Every accepted bid lands in an append-only log with a millisecond server timestamp and a monotonic sequence number; database triggers refuse edits and deletes, so no API, UI, or administrator can rewrite auction history. A scripted acceptance run against real Postgres and Redis passed all 18 checks, from increment enforcement and idempotent retries to a single close with the winner taken from the log.

Payments span two regulatory regimes. Every seller, order, and payout belongs to exactly one Stripe entity, Australia on Connect Express, UAE on Connect Custom, and the entity is a required argument on every payment operation, so a charge cannot silently route through the wrong platform. The commission engine resolves rates by precedence with VAT or GST on fees as its own line in every money breakdown; refunds reverse commission in the same transaction; paid orders sit in escrow states until delivery confirmation and a configurable dispute-hold window before payout release.

Sellers get a full lifecycle, application queue, Stripe-hosted KYC, product listing with presigned media uploads, scheduled shows, go-live broadcasting with second-camera pairing, shipping labels through EasyPost and Aramex, and earnings with CSV export, mirrored across the mobile app and the web seller console. Staff operate an 18-section admin panel with five server-enforced roles, an append-only audit log, and the ability to join any live stream silently for moderation.