I spent weeks reading everything YC has ever published about what they look for. here are 9 things that would have changed how I thought about the application

Don’t try to decode a YC partner’s “Interesting.” Pay attention to what they ask next. - Retention. Do users keep coming back? - Growth. Where are new users coming from? - Competition. What do existing products get wrong? - Numbers. Do you know your metrics, and can you explain them? - Users. What have you learned that surprised you? These are the areas YC says it explores in interviews. “Interesting” doesn’t tell you whether you’re getting in. The questions matter. Your answers matter more. Know your business. Not your script.

This is basically what Michael Seibel has said for years at YC, keep investor emails short enough to read in 60 seconds, clearly explain what you do and why it matters, then stop. The wording tweaks for people who aren’t already interested almost never move the needle, volume and clear filtering do

The most important thing to do in the 48 hours after you submit your YC application: Stop improving it. - The founders who keep tweaking after submission: drive themselves into anxiety spirals. - The founders who close the tab and build: accumulate 6 more weeks of traction before the interview. The interview is 6 weeks after submission. 6 weeks of building > 6 weeks of refreshing your email.

Stop calling it product-market fit just because people are paying you. Revenue tells you people are willing to pay. Retention tells you whether they keep finding value. YC has repeatedly emphasized that building something people want is about customer behavior, not just a good-looking dashboard. Here are 8 signals to look for: - Retention. Users keep coming back. If every month you're replacing customers who leave, you have an acquisition engine, not necessarily PMF. - Repeat usage. People use your product because they need it, not because you keep sending emails reminding them to come back. - Customer love. Ask users how disappointed they'd be if your product disappeared tomorrow. The Sean Ellis benchmark is 40% saying "very disappointed." It's a useful signal, not a guarantee. - Word of mouth. Customers recommend your product to others without being asked. They're willing to put their own reputation behind it. - Customer dependence. When something breaks, users contact you because they need it fixed. They don't simply disappear and find another tool. - A clear customer segment. Your best users often have something in common. Understand who they are, what problem they have, and why your product works particularly well for them. - Willingness to pay. Customers renew, upgrade, or pay without needing constant discounts and persuasion. - Organic demand. People start discovering your product through existing users, communities, and recommendations. You're not the only one pushing it. These signals look different depending on the product. A daily-use app and an enterprise tool used once a month shouldn't have the same retention expectations. And don't confuse a few happy customers with a scalable business. You still need a large enough market and a way to reach more people like them. Before spending more money on marketing, answer these three questions: - Which 10 customers would genuinely miss your product if it disappeared? - What specific problem does your product solve for them? - Are more people with the same problem willing to pay for it? If you can't answer these, you may have customers, but you might not have product-market fit yet. Don't just measure how many people try your product. Understand why they keep using it.

What to do after you hit submit on YC Application... The application is in. The interview is not guaranteed. The work that matters now is the same work that gets you in. - Keep talking to users. One more conversation this week is better interview prep than rereading the form. - Ship something small. A fix, a new user, a clearer number. Progress between apply and interview is visible. - Write down the weak spots. Partners will ask. Having the honest version ready beats inventing one in the room. - Know your one sentence cold. Who is stuck, what it costs them, what you built. Say it out loud once a day. - Ignore the wait. Decisions for on-time applications come by December 11. Checking email does not move the date. - If you get a no, treat it as data. Note what was missing. Apply again with progress. About half the batch did exactly that. The batch starts in January. The founders who get in are usually the ones who kept building while they waited. Do the next customer conversation. That is the only prep that counts.

The hidden advantage in applying as a solo founder Ironically: solo founders who get in have made the partner conversation easier. There's no co-founder dynamic to evaluate. No equity split to probe. No role ambiguity to uncover. The entire interview: focuses on the company. - The solo founder's challenge: traction. - The solo founder's advantage: simplicity. One person who's built something real: is a cleaner investment thesis than two people still figuring it out.

A 10-minute application could get you $50,000. No equity. No reporting. No strings. The Basis Fellowship: • $50K, spend it on anything • Open to anyone: engineers, scientists, operators • Applications always open, they read every one • Didn't make it? They may still send you $3K • Advisors include a former NASA astronaut and a Sequoia partner Your application never expires. Update it whenever you build something new.

Y Combinator Winter 2027 batch applications close soon! After you apply, @convex has a perk for you! Just fill out the form here: convex.link/ycw27app Good luck founders!

This is the best example of “make something people want their agents to do.”

The paradox of getting into YC, the more you treat it as the goal, the less likely you are to do the things that actually get you in. Just build and talk to users. The application becomes obvious later

starting january 2027, 16vc will be actively investing $100k–$2m in pre-seed and seed startups across: - healthcare - biotech & life sciences - ai - fintech - femtech - saas we remain open to exceptional founders in other industries too, but the evaluation timeline and investment process may take longer. building something ambitious? we'd love to hear from you.

A healthy step-up from seed to Series A is roughly 2x to 2.5x, not 5x. If your seed valuation was so high that the A cannot reasonably step up 2x on real metrics: → You trapped the next round. If the seed valuation is a number your Series A metrics can support: → The path stays open. Leave room for an honest next price.

The YC insight about raising before you need it Every great YC founder has said some version of this: "Raise when you don't need to. Because the conversations you have when you don't need money are completely different from the conversations you have when you do." When you don't need money: you're selective. You're confident. You're patient. When you do need money: you're desperate. It shows. The terms reflect it. Raise a round before you need the next one.

The raw truth about "making something people want" The hardest part is not finding what people want. It's building it without adding all the things they didn't ask for. Every startup that starts well eventually faces the temptation: "We could also do X. And Y might be interesting. And Z would attract a different segment." The companies that resist this: deepen their product for the users they have. The ones that don't: spread thin and confuse everyone.

The most underrated YC advantage: The bathroom conversations. The things founders say to each other between sessions. The 11pm debugging sessions. The honest conversations about what's not working. Partners give tactical advice. But the founder who sits next to you at dinner and says "we tried that, here's why it failed and here's what actually worked": that's the most valuable YC education. And it's only available if you're in the room

The pattern across every YC company that raised $10M+ at Demo Day All of them started fundraising conversations before applications closed. Meaning: they had investor relationships from prior funding, or from being public on X, or from YC alumni introductions. Demo Day for them: was not a cold introduction. It was the closing event of a relationship that started months earlier. Build investor relationships 6 months before you need them

What YC Says: few people will agree with you at the start. Kalshi’s Series A deck is a masterclass in why that’s fine

YC application data Applying 2, 3, or 4 times is common. - Up to half of every batch got rejected before they got in. If one “no” makes you hate the whole process - founder life will feel worse. Resilience is the real filter. Treat the rejection as a build cycle, not an identity. Ship, get users, make progress, then reapply. That’s the signal they want.

The pattern in every rejected application: The founder spent 70% of the application describing what they will build. The pattern in every accepted application: The founder spent 70% of the application describing what they have already built and who is already paying for it. Future tense = plans. Past tense = evidence. YC funds evidence.