Intuit·Software Engineer·Onsite - System Design / Architecture·Senior

Senior

May 2026

Summary

System design round at Intuit for a software engineering role. One question, pretty open-ended, and I spent a good chunk of time second-guessing my own assumptions about how bidding should even work.

Questions Asked (1)

Design a marketplace where freelancers can bid on contract jobs, with the lowest bid winning the contract.

System DesignData ModelingTechnical Trade-offs

Author's notes

I jumped straight into the bidding flow and completely skipped scoping the user types for like the first five minutes.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and scale, then design the core entities and bidding workflow. Focus on the auction mechanism, data consistency, and trade-offs between lowest-bid-wins and quality. Conclude with scalability and fairness considerations.

Pro tip: Acknowledge that lowest-bid-wins can incentivize race-to-the-bottom quality; propose safeguards like bid validation, reputation systems, or hybrid models to show product thinking.

1. Clarify Requirements and Scale

Ask about user volume, job posting frequency, bid concurrency, and whether real-time updates are needed. Define success metrics like fairness, latency, and cost.

2. Design Data Model and Core Entities

Outline entities: User (freelancer/client), Job, Bid, Contract. Define relationships and key attributes (e.g., bid amount, timestamp, status).

3. Define Bidding Workflow and Auction Logic

Describe how freelancers submit bids, how the lowest bid is determined, and how the contract is awarded. Address tie-breaking and bid validity.

4. Address Consistency, Concurrency, and Fairness

Explain how to handle concurrent bids, prevent race conditions, and ensure the lowest bid wins. Discuss locking, transactions, or optimistic concurrency.

5. Scale and Trade-offs

Propose scaling strategies (sharding, caching, queues) and discuss trade-offs of lowest-bid-wins (quality vs. cost) and potential mitigations.

Key Points to Mention

Database schema for jobs, bids, and contracts with appropriate indexes.
Concurrency control mechanisms (e.g., optimistic locking, distributed locks) to handle simultaneous bids.
Auction closing logic: how to determine the winner when bids are equal or when bids arrive near deadline.
Trade-offs of lowest-bid-wins: risk of low-quality work, need for reputation or escrow systems.
Scalability considerations: partitioning by job ID, using message queues for bid processing.
Fairness and anti-sniping measures: bid visibility, time extensions, or sealed bids.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.