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

Senior

May 2026

Summary

PM interview at Google with a classic build vs. buy question. Nothing tricky on the surface but the depth they expected was real.

Questions Asked (1)

Your team needs a new system. Walk through how you'd decide whether to build it internally or purchase an existing solution, covering factors like cost, time-to-market, scalability, maintenance burden, vendor lock-in, and strategic differentiation.

Product StrategyTechnical Trade-offsRoadmap Prioritization

Author's notes

I started with cost and time-to-market because those felt safest, but I could tell partway through that wasn't landing as the interesting part.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by clarifying the strategic context and the problem the system solves, then evaluate build vs. buy against a consistent set of criteria weighted by business priorities. Conclude with a recommendation that balances short-term needs with long-term strategic flexibility, and outline next steps for validation.

Pro tip: Frame the decision as a portfolio choice: not every system needs to be a differentiator, so reserve build resources for areas of core strategic value and buy or partner for commodity capabilities. Also, consider a hybrid approach where you buy the base and build only the differentiating layer on top.

1. Clarify Strategic Context and Requirements

Define the problem, business goals, and must-have requirements. Identify whether the system is core to your competitive advantage or a supporting capability.

2. Evaluate Build vs. Buy Against Key Criteria

Assess each option on cost (TCO), time-to-market, scalability, maintenance burden, vendor lock-in, and strategic differentiation. Use a weighted scoring model to compare objectively.

3. Consider Hybrid and Alternative Options

Explore hybrid approaches (e.g., buy core, build extensions), open-source solutions, or partnerships. Evaluate trade-offs of each.

4. Make a Recommendation with Rationale

Synthesize findings into a clear recommendation, highlighting key trade-offs and risks. Align with stakeholders on the decision.

5. Define Next Steps and Validation Plan

Outline a plan to validate assumptions (e.g., pilot, prototype, vendor trial) and measure success. Include a contingency plan.

Key Points to Mention

Total Cost of Ownership (TCO): Include not just purchase price but integration, training, ongoing maintenance, and opportunity cost of engineering resources.
Time-to-Market: Buying can accelerate delivery, but customization may delay; building takes longer but can be tailored.
Scalability and Performance: Assess whether the solution can grow with your needs and handle expected load.
Maintenance Burden: Consider ongoing engineering effort, updates, security patches, and support.
Vendor Lock-in: Evaluate switching costs, data portability, and contractual flexibility.
Strategic Differentiation: Determine if the system provides competitive advantage; if not, buying is often better.

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