Auctions & live bidding
BidArena
Financial correctness under real-time contention
A real-time auction platform where sequencing is authoritative and settlement idempotent. A late bid or a double charge is a correctness bug, not an edge case.
This example comes from the technical delivery experience behind AussieSync. It does not necessarily represent a project contracted directly through AussieSync.
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01 Problem
In live bidding, a late bid or a double-charged wager destroys trust in the whole platform.
- Bids arriving within milliseconds of each other need one authoritative order.
- Network latency means the client’s view of "who is winning" is always slightly stale.
- A retried settlement could charge a bidder twice for a single winning bid.
- Disputes require proving after the fact exactly what happened and when.
02 The solution
Authoritative server-side sequencing with idempotent settlement and a full audit trail.
- The server, never the client, assigns the definitive order of incoming bids.
- State is pushed over persistent connections so every participant converges quickly.
- Settlement is idempotent, so a retry after a timeout cannot charge twice.
- Every state transition is written to an append-only audit log for dispute resolution.
03 Technical approach
Every choice earns its place.
- Go & Node.jsReal-time bid sequencing with predictable latency.
- WebSocketPushes authoritative state to every participant.
- RedisHot auction state and contention control.
- PostgreSQLDurable records plus the append-only audit log.
04 Outcome
Provably fair, tamper-resistant competition with financial correctness under contention.
- Provably fairserver-authoritative bid sequencing
- Correctsettlement under concurrent contention
- Auditableevery state transition, for disputes