What It’s Really Like to Interview at Y Combinator

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What’s it like pitching your startup to Sam Altman and the Twitch founder in a 10-minute lightning round?

That’s exactly what we experienced when Hoxton Mix was invited to interview at Y Combinator’s Mountain View headquarters — the world’s most prestigious accelerator program and the launchpad for companies like Airbnb, Stripe, and Dropbox.

Our Interview Experience

Representing Hoxton Mix were Chris Sees (CEO) and Ben Rometsch (CTO). We were interviewed by a panel of Y Combinator partners that included Sam Altman and Justin Kan, co-founder of Twitch.

Despite only lasting 10 minutes, the interview was intense. The YC team fired a rapid series of questions touching on every aspect of the business — from user acquisition and burn rate to technical defensibility and team dynamics.

We focused on demonstrating the strength and potential of our web and mobile applications, designed for remote-first businesses to manage incoming post through scanning, forwarding, shredding, and secure access. We also showcased our telephony tools, which enable teams to handle calls without a physical office.

After the first round, we were told that shortlisted teams would be invited back for a second interview. A few hours later, we received confirmation — we had made the shortlist. We returned later that day for another fast-paced, 10–15 minute session with the partners, diving even deeper into product details, market size, and our vision for scaling the platform globally.

Being invited to interview was a proud moment — and a validation of the platform we've spent years building. We left energised and more focused than ever.

What Y Combinator Looks For

Y Combinator is known for prioritising three key qualities in startups:

1. A strong founding team
   They want to know you can survive the tough times. Having co-founded multiple ventures together, we showed our resilience and alignment as a team.
2. A big market opportunity
   We demonstrated our understanding of the shift to remote work and how businesses globally need better ways to manage physical post digitally — with privacy, compliance, and control.
3. Relevant experience and execution
   Execution beats ideas. Our experience building SaaS products, combined with existing customer traction, helped us make the case that we could deliver.

Tips for Other Founders

If you’re applying to YC or another elite accelerator, here’s our advice:

• Be sharp and succinct — they expect fast, direct answers
• Know your numbers cold: MRR, burn rate, CAC, conversion, and churn
• Don’t just talk — demonstrate why your team is the one to bet on
• Be prepared for curveball questions (see below!)

Typical Y Combinator Interview Questions

Here’s a list of questions that Y Combinator partners are known to ask — we were asked some of these ourselves:

• What are you working on?
• Have you raised funding?
• What makes new users try your product?
• What competition do you fear the most?
• What's the worst thing that has happened to your startup?
• Will you reincorporate as a US company?
• What's an impressive thing that your startup has accomplished?
• Where is the rocket science in your product?
• Why did you choose this idea to work on?
• Why do reluctant users hold back from using your product?
• Who would you hire, or how would you add to your team?
• What problems/hurdles are you anticipating?
• Who is "the boss" of your startup?
• What is the next step in your product evolution?
• What obstacles do you expect to face, and how will you overcome them?
• Who needs what you're making?
• How does your product work in more detail?
• What are you going to do next?
• What do you understand about your product or market that others don't?
• Where do new users come from?
• How big is the opportunity for your product or service?
• Six months from now, what's going to be your biggest problem?
• What's the funniest thing that has happened to you during your startup journey?
• Tell us something surprising that you have done.
• Who are your competitors?
• What's new about what you make?
• How many users do you have?
• Why isn't someone already doing this?
• What are the top things that users want?
• What is your burn rate?
• How do you know customers need what you're making?
• What domain expertise do you have?
• What makes your product or service different from existing options?
• What's your conversion rate?
• What systems have you hacked?
• Who would use your product or service?
• How will customers and/or users find out about you?
• Why did your team get together?
• In what ways are you resourceful?
• What is your distribution strategy?
• What has surprised you about user behaviour?
• What part of your project are you going to build first?
• What resistance do you expect from potential users, and how will you overcome it?
• How do you understand customer needs?
• What's the biggest mistake that you have made with your startup?
• Who might become your competitors in the future?
• What do you understand about your users and their needs?
• What is your user growth rate?
• What are the key things about your field or market that outsiders may need help understanding?
• Who will be your first paying customer?
• If your startup succeeds, what additional areas might you be able to expand into?
• Who would be your next hire?
• How do you know there is a demand for your product or service?
• Would you consider relocating to Silicon Valley?
• What do you know about your market or product that others may not know?
• How much money could you make per year?
• How long can you go without funding?
• How will you make money?
• Will your team stay together for the long haul?
• How much does customer acquisition cost?
• How did your team meet?
• Who on your team does what?
• How are you meeting customers?
• How many users are currently paying

Final Thoughts

Whether or not you're applying to YC, preparing for this kind of interview is a great exercise in refining your thinking, focus, and pitch.

We’re proud to have made it to the interview stage — and hope our experience helps the next generation of founders prepare.

FAQ

What is Y Combinator?

Y Combinator is a world-renowned startup accelerator based in Silicon Valley. It has helped launch successful companies like Airbnb, Stripe, Dropbox, and GoCardless.

What is the Y Combinator interview process like?

The Y Combinator interview is fast-paced and intense. Founders are asked a rapid series of questions by YC partners to evaluate the team, the idea, and the startup’s potential. Each interview typically lasts just 10–15 minutes.

What are the key factors that Y Combinator looks for in a startup?

Y Combinator looks for three things: a strong founding team, a large market opportunity, and relevant experience executing the idea. They also value founder resilience and deep understanding of the problem space.

How did Hoxton Mix prepare for the Y Combinator interview?

We focused on the three areas Y Combinator values most: strong founder alignment, a large and growing market, and experience executing on the opportunity. We also prepared thoroughly for typical YC interview questions — and were later shortlisted for a second interview.