Y Combinator Interview Advice + Live Practice Sessions

Kwindla Hultman Kramer
Published in
6 min readOct 27, 2016


tl;dr: Our company, Daily.co, was part of the Y Combinator W16 batch. I’m always happy to give advice about YC applications and interviews. Below are some notes about how to prepare for an in-person interview. I’m always happy to be helpful to startup founders and people trying to break into tech, if I can be. Feel free to schedule a Daily.co video call with me, here.

Over the past few months I’ve received a number of calls from friends of friends who are applying to Y Combinator. These conversations often cover similar ground, and, since YC interview acceptances just went out, I thought I’d write up my notes on preparing for the in-person YC interview.

A few good posts to read

I found a few posts particularly useful when we were practicing for Pluot’s interview.

  • Jessica Livingston and Michael Seibel have both posted short, numbered lists of things to keep in mind about the interview. If you only read two things, and only follow this advice, you’ll do fine!
  • Michael also wrote a blog post about how to pitch your company, which is not specific to YC interviews but is very much worth reading and internalizing.
  • Danielle Morrill wrote a comprehensive and thoughtful overview of how to approach the interview.
  • This Quora thread includes some excellent answers to the question “What is it like to interview with Y Combinator.”

What does your company do?

The interview is short — approximately ten minutes. It goes by fast. It’s in your interest to help your interviewers cover as much ground as possible. That means all of your answers should be concise. I’ll come back to how we practiced for our interview, below. But keep in mind, for everything you say in the interview, short is better than long. Simple is better than complicated.

The first question will almost certainly be “what does your company do?” You need a great answer to this.

Your answer should be completely free of jargon, acronyms, and buzzwords. And, again, your answer should be short. Thirty seconds at most. Use plain language. Include an example. “We make software that automatically re-configures corporate networks when denial of service attacks happen. For example, one of our test networks stayed up and running last week during the entire Mirai botnet attack, even though other, similar networks, had two days of downtime.”

Team, market, and traction

After “what does your company do,” the broad topics your interviewers will want to cover are team, market, and traction. Your job, in the interview, is to be clear, concise, honest, and positive — all at the same time — about how your company looks when viewed through the lens of “team, market, and traction.”

Here’s how I think about those three elements of a startup’s story: everything always comes back to whether the team can innovate, execute, learn, iterate, and persist. These days you have to offer pretty solid evidence that your team is great in order to get accepted to Y Combinator.

Traction is the single best way to provide evidence that you’ll succeed. Keep in mind, though, that your traction metric needs to be relevant and concrete to be convincing. Month-over-month revenue growth at a non-trivial scale is by far the best metric to talk about, if you can. But some other tangible, relevant metric can be useful, too: daily active users, number of Xs that people Y on your platform every day, etc.

Alternatively, a well thought through approach to attacking a very large market, plus a great tech demo, plus the ability to think on your feet and communicate well, is another way to provide that evidence.

See the relative “complexity” of those two paths? Traction — especially revenue traction — is its own story. If you’re applying to YC with, say, $150k/month of recurring revenue and revenue is growing 30% each month, your interview is probably going to go pretty well. :-)

On the other hand, without traction, you are implicitly explaining, in the interview, why you don’t have traction yet. So, your story might be something like: “we started development nine months ago, signed up 10 beta customers (non-paying) six months ago, and over the last two months have converted four of those into paying customers. They’ve signed contracts to pay us $10k each for pilots. Another beta customer signed an LOI worth up to $5M if we can prove in a pilot that we reduce their downtime by 20%.”

Basically, you’re saying, “we get things done fast, we’ve proven that we can deliver something customers are willing to have a conversation about paying for, and we have the beginnings of proof that customers are actually willing to pay, and how much.”

My advice is to lead with traction, if you have it. If you don’t, think about how to frame your story as “we get things done fast — repeatedly.” By the way, that’s advice I give to early stage founders whether or not they’re applying to YC. A relentless focus on building something other people find useful is a really good organizing principle.

How we practiced

We practiced for our YC interview by assembling a list of about 100 interview questions. We wrote down answers to all of them, then refined each answer until it was two sentences long. Every answer needed to say something about what we thought our strengths were with respect to our team, the size of our market, or what we’d gotten done so far. (We didn’t have any traction when we applied to YC. We were pre-launch.)

We wrote the questions and answers down on flash cards. Then practiced until we could answer every question verbatim, in any order. Then we practiced some more until we could answer them conversationally, but still sticking to the same core idea and just one or two sentences.

We had a hardware demo. We practiced (and debugged) until we were confident we could do the demo on demand, piecemeal, while distracted, while answering questions, and that anyone we showed the demo to could pull out a phone or laptop and interact with our prototype.

Finally, one last piece of advice. Know the definitions of basic accounting terms that are relevant to your startup: revenue, recurring revenue, gross merchandise volume, contract, LOI, margin, and profit.

Open slots for practice interviews via video call

Going through a YC batch is fun, useful, and a great opportunity. But on top of all that, YC is a community of founders who are all going through similar things and all love what they’re doing. That’s something that’s worth seeking out, whether you do it by applying to Y Combinator, or in another way.

My favorite thing about startup communities is how supportive founders are of each other. Most of us are genuinely excited to learn about what other people are working on, and genuinely interested in being helpful. In that spirit, a bunch of us have carved out time on Monday and Wednesday next week to do video calls with people preparing for YC interviews. We have 20 minute slots available here at this Calendly link. We’ll do a mock interview for the first 10 minutes, then talk more generally for the second 10 minutes. Please feel free to sign up. We’d love to meet you.

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Kwindla Hultman Kramer

Daily.co (formerly Pluot), Oblong, Media Matters for America, AllAfrica - https://daily.co/