Overview
We designed and built a real-time auction platform capable of processing thousands of concurrent bids across multiple auction rooms. The system required strict bid ordering, sub-100ms end-to-end latency, and complete tenant isolation for white-label deployments.
Technical Challenges
The core challenge was maintaining bid ordering guarantees across a distributed system while keeping latency low enough for real-time interaction. Traditional database-centric approaches introduced too much latency, while purely in-memory approaches lacked durability.
Event-Sourced Architecture
We implemented an event-sourced architecture where every bid, auction state change, and settlement action is captured as an immutable event. This gave us:
- Complete audit trail — every action is traceable
- Temporal queries — reconstruct auction state at any point in time
- Conflict resolution — deterministic ordering via event sequence numbers
Real-Time Communication
WebSocket connections manage real-time bid streaming to all connected clients. We implemented a custom fan-out layer that:
- Maintains per-auction-room channels
- Handles connection drops and automatic reconnection
- Provides back-pressure when clients can't keep up
Results
- Throughput: 5,000+ concurrent bids per second across all rooms
- Latency: P99 bid-to-confirmation under 85ms
- Uptime: 99.97% availability during peak auction events
- Scale: Supporting 50+ concurrent auction rooms