Design an online auction platform

Q: Design an online auction platform

This question evaluates competencies in designing scalable, low-latency real-time distributed systems, covering data modeling, consistency and concurrency control, ordering and sharding strategies, real-time push/fanout, anti-fraud and escrow/payment flows within the System Design and real-time services domain.

Q: How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

Q: What difficulty level is this interview question?

This is a hard difficulty System Design question, commonly asked during Onsite rounds at Meta.

Q: What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Meta during technical interviews.

Question

System Design: Real-Time English Auction Platform

Goal

Design an online auction platform that supports English-style auctions with:

Reserve price
Bid increments
Proxy bidding (max auto-bid)
Soft close (extend by X seconds when a bid arrives near the end)
Optional Buy-It-Now

Provide:

Functional APIs: CreateAuction, PlaceBid, GetAuction, SubscribeAuctionEvents, CloseAuction.
Data model: Users, Items, Auctions, Bids, Watchlists, Payments.
Real-time push mechanism for live bid updates.
Consistency model for determining the winning bid; idempotency and concurrency control for PlaceBid.
Anti-sniping (soft-close) and fraud prevention measures.
Escrow/payment flow and auditability.
A scalable architecture for 500k concurrent auctions, 5M watchers, and p99 bid-to-UI latency < 200 ms.
Sharding/partitioning strategy, ordering of bids across partitions, failure recovery for auction finalization, backfill/replay, security, and key metrics/alerts.

Assume auctions are public, with authenticated users, and a single logical region for writes (multi-AZ) with read replicas/edges for fanout. Buy-It-Now is available until reserve is met or the first qualifying bid is placed (configurable).

Design an online auction platform

Quick Overview

System Design: Real-Time English Auction Platform

Goal

Solution

Comments (0)