
General Partner @YCombinator, Co-Founder @FutureAdvisor (YC S10), MIT EECS
San Francisco, CA
Joined June 2007
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- Following380
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Jon Xu retweeted
Startup School is coming to Taipei on November 12! 🇹🇼
Hear from founders like @andyfang of DoorDash, @jeffchanginvest of Vest, @moseslo of Xendit, @mchiang0610 of Ollama, and more.
And join builders and hackers from across Asia for a day of talks and sessions with YC partners.
Jon Xu retweeted
people are saying
Theo - t3.gg@theoSep 11United States
United StatesConnected via United States App StoreAccount-level information, not a live location or per-post device.
Current YC batch is one of the best of all time. Also one of the most undervalued.
Jon Xu retweeted
CNBC + @garrytan filming live from the hardware floor of @ycombinator Demo Day!
They are sitting within 20 feet of teams building jet-powered interceptors, military exoskeletons, humanoids, cargo rockets, drones that can move clouds...
Jon Xu retweeted
We're giving enterprise buyers an early look at YC companies building AI tools for them. Apply now if you're interested in joining and attending our first event with the Fall '26 batch at YC SF, Oct 22.
Introducing the YC Early Access Network.
4x a year, senior technology leaders get early looks at YC's enterprise AI companies and help shape their roadmaps.
Invite-only, by application. Fall '26 kicks off Oct 22 in SF.
Apply now: events.ycombinator.com/yc-ea…
Jon Xu retweeted
Legora's revenue has increased by over 9x from this time a year ago. That's an astounding growth rate for a company of this size. It's not unusual for a startup to grow that fast in the first 6 months, but Legora is 3 years in.
The momentum continues at @WeAreLegora ...we beat our original Q3 '26 plan a full month early. July was the strongest quarter-opening month in Legora's history, and August was even larger.
Total net new ARR grew 36% MoM.
But the story of the month is in-house teams. ARR from in-house is up 15x+ YoY, average ARR per in-house customer is up 2.5x+ YoY, and in-house teams are now almost half of our total new customers.
Most importantly, you earn ARR by building the best product on the market. Our usage climbs every month: 16+ hours per monthly active user.
In September, we expect to add more ARR than in all of Q1 '26 combined, which would make Q3 the best quarter in our history and capture yet another ARR milestone.
LFG!
Jon Xu retweeted
Introducing @robocurve, a Public Benefit Corporation to measure and report frontier robotics capabilities.
We build real-world evaluations for robots and publish results as a neutral third party.
Jon Xu retweeted
We’ve started moving onto longer-horizon tasks.
Table bussing - π0.5 completed 48/50 rollouts on a consistent setup. Very much in distribution, but a useful baseline.
Jon Xu retweeted
YC invented the SAFE a decade ago, simplifying the process of raising seed money for founders across the world.
Today, we’re releasing a SAFE tool to make it even easier to raise your seed round on SAFEs. And it’s free!
In 2013, @cjoneslevy created the SAFE at YC. It's since been used by YC founders to raise $15B+ and has become the standard way startups raise money.
So we're launching Send a SAFE: a free tool to generate, sign, & send one in ~2 minutes, built to be used by founders (and their AI agents).
Jon Xu retweeted
Today we're launching @akonlabs backed by @ycombinator
We build GitNexus, an open-source knowledge graph for your repository. Coding agents query it to get exactly the context a task needs symbols, call paths, dependencies instead of grepping around and stuffing half your codebase into a context window.
Context is the bottleneck for coding agents. Bigger windows haven't fixed it. Buyers of agents are paying more per token to get worse code, and the agents themselves have no map of the repo they're editing.
We're fixing this. On DeepSWE, the same agent with GitNexus vs. without:
1. 37% → 68.4% of tasks passed
2. Half the cost per fix
3. On the hardest tasks, the gap more than triples
One stack: knowledge graph, coding agent, automated PR review. Managed, self-hosted, or air-gapped.
45k GitHub stars. 65k weekly npm downloads. 10+ enterprise deployments.
Sign up at: app.akonlabs.com
Jon Xu retweeted
If you're an MIT alum or MIT intern in the bay, and you're interested in startups:
Come by the YC office next week for happy hour!
events.ycombinator.com/mit-y…
Jon Xu retweeted
Hosted the first YC Intern Expo today with 1,400 college students & 52 YC companies hiring interns.
Many of YC's best founders started as interns. From the people I met, pretty sure we'll get more from this crowd.
Jon Xu retweeted
Yesterday we had dinner with @paulg at @ycombinator's office. And it was by far the most information-dense conversation I have had in my life.
I do not think there is another place where you can get this much timeless startup advice in one room.
Three things I wrote down:
1️⃣10% week-over-week growth is all you need to care about. It's impossible to mess it up as a founder if you maintain this growth for a long enough period.
2️⃣Great startups ride second waves that propel them to be truly huge. Zuckerberg could not have predicted the coming of the iPhone 3 years after he started. Replit grew from 1M to 100s of millions in revenue in one year from vibe coding. Boom Supersonic couldn't have predicted that there will be such demand for their engines to power AI data centres. You cannot time the wave but it's about being alive long enough to catch it.
3️⃣Formidable founders are deeply committed to what they are building. They survive the hard years because giving up is not an option. They eventually get what they want because they keep going when most people would have stopped.
I could have listened for another five hours. What an absolute pleasure to have met him in person.
Jon Xu retweeted
Everyone in robotics is waiting for the ChatGPT moment but … missing the most important part of the ChatGPT playbook.
So we left Boston Dynamics and Amazon Robotics to fix that, and start @Shiraz_AI to build robots that learn on the job.
When GPT-3 was released, it couldn’t do every task out of the box. But you could show it a few examples in the prompt, and it adapted on the spot.
We’re bringing that to robotics.
Show our robot a task once, and it adapts on the spot.
That’s exactly what our manufacturing customers need, especially when production lines change every week and traditional automation can’t keep up. And we’re already deploying it with our first customers.
Have a factory that’s difficult to automate? We’d love to talk.
Jon Xu retweeted
Introducing the Halluminate Westworld Finance Diligence Bench: 88 problems that put AI agents through a full company acquisition due diligence process.
We tested a range of models across several harnesses. Results below.
🧵1/
Jon Xu retweeted
a patient verifies their identity once.
in a couple clicks, @hubblehealthai assembles their medical records from across their providers for your AI agent to use.
we connect into EHRs and HIEs, and leverage browser and voice agents so you don't have to do any work.
Jon Xu retweeted
It's exciting to see the launch of RVII and the focus on the YC ecosystem. I enjoyed this conversation with @richaberman and @spintopeyronel!
Early-stage investing has historically been difficult for everyday investors to access and even harder to understand.
This roundtable with leaders from Robinhood Ventures and Y Combinator offers a closer look at how Y Combinator works and how Robinhood Ventures Fund II is building a more accessible model. youtube.com/watch?v=478LhKpF…
Jon Xu retweeted
At Startup School this year, we interviewed 8 awesome ML student researchers at their posters during "YCML", our inaugural research symposium.
@ycombinator is funding more research-focused companies than ever before, and we were thrilled to see a huge overlap between students interested in research and startups.
Check out their awesome work below in thread.
Jon Xu retweeted
Today, we’re proud to launch Buildbox with @ycombinator 🌟
Most AI agents don’t fail where teams are looking. They pass evals, their traces look normal, and the agent says it completed the task. Then the customer asks again, redirects it, or gives up. There’s no obvious error or failed trace…but the user still didn’t get the outcome they wanted.
Buildbox finds those hidden agent failures, organizes them by task, and gives teams evidence-backed fixes they can review and ship.
If you’re building customer-facing AI agents, let’s chat! heybuildbox.com
Jon Xu retweeted
The deadline to apply for YC's fall batch is today at 8pm PT. Filling out an application takes ~30 minutes.
“This is absolutely the single greatest time to start a company, I’m jealous of all of you” @JensenHuang at Startup School





































