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eBay·Product Manager·Onsite - Product Sense / Strategy·Senior

Senior
Apr 2026

Summary

PM interview at eBay with a classic build vs. buy question. Not a lot to go on but it's the kind of thing that trips people up if they haven't thought through the tradeoffs before walking in.

Questions Asked (1)

Q1

How do you decide whether to build a solution internally or purchase an existing one?

Product StrategyTechnical Trade-offsRoadmap Prioritization
Author's notes

This sounds straightforward until you're actually sitting there and realize there are like six different dimensions pulling in different directions.

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AI HintsAI Generated

Suggested Approach

Start by framing the decision as a strategic choice tied to eBay's business goals, not just a cost comparison. Walk through a structured evaluation that weighs user needs, competitive differentiation, total cost of ownership, and speed to market. Conclude with a recommendation that balances short-term delivery with long-term scalability and innovation.

Pro tip: Emphasize that 'build vs. buy' is rarely binary—consider hybrid approaches like buying a core platform and building proprietary extensions on top. Also, quantify the opportunity cost of engineering time in terms of delayed roadmap items, not just dollars.

1. Clarify the problem and strategic fit

Define the specific user problem and how solving it aligns with eBay's strategic priorities (e.g., buyer/seller experience, trust, scalability). Determine if the capability is core to eBay's competitive advantage or a supporting function.

2. Evaluate internal capabilities and opportunity cost

Assess whether eBay has the engineering talent, time, and infrastructure to build and maintain the solution. Quantify the opportunity cost of diverting resources from other high-impact roadmap items.

3. Assess external solutions and total cost of ownership

Research available vendors, their maturity, integration effort, and long-term costs (licensing, customization, support). Consider risks like vendor lock-in, data security, and roadmap misalignment.

4. Weigh speed, differentiation, and flexibility

Compare time-to-market, potential for competitive differentiation, and ability to iterate quickly. Buying may accelerate delivery but limit customization; building offers control but requires significant investment.

5. Make a recommendation with a hybrid lens

Synthesize findings into a clear recommendation, often proposing a hybrid approach (e.g., buy core, build extensions). Define success metrics and a plan to revisit the decision as conditions change.

Key Points to Mention

  • Core vs. context: build what differentiates eBay, buy what is commodity
  • Total cost of ownership (TCO) including integration, maintenance, and switching costs
  • Opportunity cost of engineering resources and impact on roadmap velocity
  • Vendor evaluation criteria: scalability, security, compliance, and cultural fit
  • Speed to market and competitive pressure
  • Hybrid approaches and exit strategies to mitigate lock-in

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