← Early-stage Startup Interview Insights

Early-stage Startup·Software Engineer·Onsite - Multi Round·Intermediate

IntermediateOffer
Jun 2026

Summary

Interviewed at a tiny startup (former Xbox and Microsoft AI folks) for a software engineer role. The process was a full gauntlet: OA, technical screen, then an onsite with multiple rounds including a CTO chat. Somehow walked out with an offer the next day despite bombing chunks of it.

Questions Asked (3)

Q1

Given a 3D chessboard, find the shortest path from point A to point B using a knight that moves in an L-shape (±2 in one axis and ±1 in another). Then optimize your solution to O(n).

Algorithms & Data Structures
Author's notes

Did not know 3D chess was a thing.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by modeling the 3D chessboard as a graph where each cell is a node and knight moves are edges, then use BFS to find the shortest path. For optimization, recognize that BFS on an unweighted graph is already O(n) where n is the number of cells, but if the board is large, consider bidirectional BFS or A* with a suitable heuristic to reduce the search space. Finally, discuss how to achieve O(n) by ensuring each cell is visited at most once and using efficient data structures.

Pro tip: Mention that the knight's move graph is bipartite, so the shortest path length can sometimes be computed analytically, but BFS remains the standard approach. Also, clarify that O(n) refers to the number of cells, not the side length, to avoid ambiguity.

1. Clarify the problem

Ask about the board size, whether it's finite or infinite, and if there are obstacles. Confirm that 'shortest path' means minimum number of moves.

2. Model as a graph

Represent each cell as a node and each valid knight move as an edge. This transforms the problem into finding the shortest path in an unweighted graph.

3. Apply BFS

Use Breadth-First Search from point A to explore moves level by level until B is reached. This guarantees the shortest path in O(V+E) time, which is O(n) for a 3D board with n cells.

4. Optimize if needed

If the board is very large, consider bidirectional BFS or A* with a heuristic like Manhattan distance divided by 3. Discuss trade-offs between time and space.

5. Analyze complexity

Explain that BFS visits each cell at most once, so time complexity is O(n) where n is the number of cells. Space complexity is also O(n) for the queue and visited set.

Key Points to Mention

  • BFS guarantees shortest path in unweighted graphs
  • Time complexity O(n) where n is number of cells
  • Space complexity O(n) for visited set and queue
  • Possible optimizations: bidirectional BFS, A* with heuristic
  • Handling of boundaries and invalid moves
  • Bipartite nature of knight's move graph (optional)

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

Q2

Why do you want to join this company?

Adaptability & Ambiguity
Author's notes

First in-person round was just this.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Show genuine enthusiasm for the company's mission and product, and connect it to your own career goals and technical interests. Emphasize your comfort with ambiguity and desire to make a tangible impact in a fast-paced startup environment.

Pro tip: Research the company's recent product launches or funding news and mention specific details to demonstrate genuine interest. Also, subtly highlight how your adaptability and eagerness to wear multiple hats align with the startup's needs.

1. Express enthusiasm for the company's mission

Start by stating what specifically excites you about the company's vision, product, or market. Show that you've done your homework and genuinely care about what they're building.

2. Connect to your skills and goals

Explain how your technical skills and career aspirations align with the company's needs and stage. Highlight your desire to contribute to early-stage development and grow with the company.

3. Emphasize adaptability and comfort with ambiguity

Discuss your ability to thrive in uncertain, fast-changing environments. Give a brief example of how you've successfully navigated ambiguity in a previous project or role.

4. Show how you can make an impact

Describe how you can contribute to the company's success, perhaps by solving a specific problem or bringing a unique skill set. Focus on the value you can add from day one.

5. Close with a forward-looking statement

Summarize your excitement and readiness to join the team, and express your eagerness to contribute to their journey. Keep it positive and confident.

Key Points to Mention

  • Specific aspects of the company's mission, product, or culture that resonate with you
  • Your comfort with ambiguity and ability to adapt to changing priorities
  • Desire to work in a fast-paced, early-stage environment where you can wear multiple hats
  • How your technical skills align with the company's tech stack or challenges
  • Examples of past experiences where you thrived in uncertain situations
  • Your motivation to make a tangible impact and grow with the company

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

Q3

Draw a system architecture diagram of the system you worked on at your last job, and walk us through it. Be prepared for detailed follow-up questions on specific subsystems.

System DesignTechnical Trade-offs
Author's notes

This one actually went better than expected.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by drawing a high-level diagram with clear boundaries (clients, services, data stores) and then walk through the primary request flow. Focus on the subsystems you know best and be ready to dive into trade-offs, bottlenecks, and scaling decisions for each.

Pro tip: Choose a system you genuinely understand end-to-end, and proactively mention one thing you'd improve or redesign today—this shows self-awareness and growth.

1. Set the context

Briefly state the product, scale (users, QPS, data volume), and your role on the team. This helps the interviewer calibrate the complexity and relevance of your diagram.

2. Draw the high-level architecture

Sketch the main components (clients, load balancers, services, databases, caches, queues) and their connections. Keep it simple and label each box clearly.

3. Walk through a core request flow

Trace a typical user action from end to end, explaining how data moves through the system and why each component exists. This demonstrates your understanding of the system's behavior.

4. Highlight key design decisions and trade-offs

For 2–3 critical subsystems, explain why you chose a particular technology or pattern, what alternatives you considered, and the trade-offs (e.g., consistency vs. availability, latency vs. cost).

5. Discuss scaling, failures, and improvements

Mention how the system handles growth, what breaks under load, and what you would change if you had more time. This shows forward-thinking and operational awareness.

Key Points to Mention

  • Clear separation of concerns (e.g., API gateway, business logic, data layer)
  • Data flow and storage choices (SQL vs. NoSQL, caching strategy, message queues)
  • Scalability mechanisms (horizontal scaling, sharding, load balancing)
  • Reliability and failure handling (retries, circuit breakers, monitoring)
  • Trade-offs made (e.g., consistency vs. latency, build vs. buy)
  • One concrete improvement or lesson learned from the system

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