Y Combinator Interview Questions

Product and Product Demand

  • What are you making?

  • How does your product work in more detail?

  • Who needs what you’re making?

  • How do you know customers need what you’re making?

  • How will customers and/or users find out about you?

  • Where do your new users come from?

  • What makes new users try you?

  • Why do the reluctant users hold back?

  • Where is the rocket science here?

  • What is the next step in product evolution?

  • What’s new about what you make?

  • What are the top things users want?

  • What has surprised you about user behavior?

  • How are you understanding customer needs?

  • Who were your first customers?

  • How are you meeting customers?

Market Size

  • How many people are in your target market?

  • How many $B is the market?

  • How fast is the market growing?

  • Who are your competitors? Who might become competitors?

  • Which competition do you fear most?

  • How many users do your competitors have?

  • How much are your competitors making?

  • How much time and money do users in your target market waste before switching to your product/service?

  • What are some trends in your target market, and related markets?


  • If your startup succeeds, what additional areas might you be able to expand into?

  • How do you think about your ASP (average selling price) over time? Do you think this will go up, down, or stay about the same? Why?

  • What could you do to expand your TAM?

  • How big is this market, really?

  • How do you know that this isn’t just for [subculture or niche user base]?

Metrics and Financials

  • What is your growth like?

  • How many users do you have?

  • What is your user growth rate?

  • How many users have ever engaged?

  • What is your burn rate?

  • What’s the conversion rate?

  • What’s the repeat buyer rate?

  • What’s the churn rate?

  • How much does customer acquisition cost?

  • What is the average price of a [purchase, subscription, etc]?

  • How many users have ever engaged?

  • How many are currently active users?

  • Total revenue

  • Total costs, fixed and marginal

  • Acquisition funnel conversion rate

  • Customer acquisition cost

User Behavior

  • How many users are paying?

  • Are your customers one-and-done, or do they come back?

  • What are other ways people solve this problem?


  • What are your numbers? (to be elaborated into more questions)

  • Why haven’t you made more progress?

Business Model

  • How will you make money?

  • Why is your product priced the way it is?

    • For marketplaces: why is your commission so high?

    • For marketplaces: why is your commission so low?

Next Steps

  • Why do you want to be part of YC?

  • What are you going to do next?

  • Would you relocate to Silicon Valley? (maybe not relevant anymore)

  • How long can you go before funding?

  • Will your team stick at this?

  • How do we know your team will stick together?

  • Are you open to changing your idea?

Challenges & Obstacles

  • What’s the worst thing that happened?

  • What’s the biggest mistake you have made?

  • What problems/hurdles are you anticipating?  How will you overcome them?

  • What will be the biggest challenge two years from now?


  • Who are your competitors?

  • Who do you fear the most?

  • What do you understand that others don’t?

  • Why isn’t someone already doing this?

  • How is your product different?

  • What, exactly, makes you different from existing options?

  • Who might become competitors?

  • What do you understand about your users?

  • What are the key things about your field that outsiders don’t understand?

  • Won’t [big company] just launch a [whatever your company does] feature and kill you?

Company History

  • Why did you pick this idea to work on?

  • Have you raised funding?

  • What’s the funniest thing that has happened to you?

  • Tell us something surprising you have done?

  • What’s an impressive thing you’ve done?

  • What systems have you hacked?

Company Formation

  • Will you reincorporate as a Delaware C-Corp?

Marketplace Questions

  • What side of the marketplace is harder, demand or supply?

  • Is it harder to find suppliers to list [whatever good or service], or buyers to buy?

  • How do you plan to build the marketplace from scratch?

  • How would it work to expand geographically?


  • How do you all know each other?

  • Who are the other founders? (If you have <10% ownership founders)

  • Why did your team get together?

  • How did your team meet?

  • Who in your team does what?

  • Who would be your next hire?

  • Who would you hire or how would you add to your team?

  • Who is “the boss”?

  • What domain expertise do you have?

  • In what ways are you resourceful?

Author: John Sillings and few others