Partner @a16z investing in infrastructure & AI

San Francisco, CA
Joined August 2010
We formally announced Mirendil less than 4 months ago. Today, I'm excited to share an important milestone for: Pretraining at scale without a pretraining team. Mirendil's mission is to solve Recursive Self-Improvement (RSI) and use it to democratize frontier AI development, ultimately accelerating science and technology. At Mirendil, when we think about RSI, we think holistically about the company as an intelligent entity that self-improves toward its goal. From that perspective, the most powerful notion of acceleration is reducing the time and resources (number of human experts, compute, and other costs) needed to achieve ambitious goals. Given that pretraining is perhaps the most important yet most challenging part of frontier AI development, we decided to run an ambitious controlled experiment: Starting fully from scratch, can we significantly reduce the time, number of human experts, and compute resources needed to go all the way to successfully pretraining a strong coding model at scale? Mirendil-Base is the result of this experiment. Our first pretrained model was built by one researcher in 3.5 months, with less than $10M in compute. This includes all the research and small-scale experiments it took to get there, as well as the final training run. The recipe holds up as the models get bigger. For reference, Mirendil-Base is in the 100B-500B parameter range, Mirendil-Base-Large in the 500B-2T range, and Mirendil-Base-XL in the 2T-10T range. We're beginning to see a world where a single researcher, empowered by AI, can take on work that once required an entire research organization. As these systems improve, the bottleneck shifts from the size of a team to the ambition and judgment of the people directing them. This has profound implications for who gets to build AI and, ultimately, who gets to push the frontiers of science and technology forward. We’ll share independent evaluations, post-training benchmarks and API-access sooner than you think so stay tuned!
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Jason Cui retweeted
Introducing Exa 3.0: our largest ever improvement to search quality. Exa is now #1 on every benchmark we tested, from public evals to verticals like coding and GTM intelligence. It's the result of multiple research breakthroughs 🧵
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Jason Cui retweeted
Our new website is live! Along with a new visual identity for Inferact. Inferact gives AI teams production inference they control, run optimized inference wherever your compute lives. Come check it out inferact.ai?url
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Jason Cui retweeted
In 2022, Berkeley PhD student Woosuk Kwon thought he could make Meta's new open-weight model, OPT-175B, run faster in two weeks. Four years and 3,000 contributors later, that project is @vllm_project, one of the largest open-source inference engines, running on ~500,000 GPUs at any given time. He and fellow researchers Simon Mo, Kaichao You, and Roger Wang borrowed "virtual memory" from operating systems, handing out memory only as it's needed so each GPU can juggle requests of wildly different sizes. (The "v" in vLLM is for virtual.) Their first user, Berkeley neighbor @arena, cut its GPU needs in half. Today Google, Amazon, and Meta all run vLLM in production. In January, the core maintainers founded @inferact and raised $150M to give vLLM a full-time team. They're hiring across eng, marketing, and devrel in SF and Singapore: a16zjobs.substack.com/p/infe… @simon_mo_ @woosuk_k @KaichaoYou @rogerw0108
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Jason Cui retweeted
muse spark open. why 2026 won't be like 1984 
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Jason Cui retweeted
🎉 Day-0 support for Meta's open-weight Muse Spark Open is live on vLLM, verified on NVIDIA and AMD GPUs as well as on TPUs! 816B parameters, 42B active per token, a 1M-token image, video and audio inputs, built for long-horizon agentic coding. We’re excited to have worked with Meta Superintelligence Labs to bring Muse Spark Open to vLLM from day one as the most capable US open-weight model. ✨ 1M context for large, complex codebases 👀 Native image, video, audio & document understanding ⚡ BF16, NVFP4 & MXFP4 support 🚀 DSpark speculative decoding on both CUDA and ROCm 1/6
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Jason Cui retweeted
If you did science fairs in high school and are interested in startups and technology, @JasonSCui, @pchopra28 and I are hosting a happy hour in San Francisco 10/27! RSVP below. luma.com/zbtk9ejh
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Jason Cui retweeted
Exa just passed $100m in annualized revenue. We've grown almost exactly 10x per year for 3 years. We now handle 2 billion requests a month from 200k+ teams. And it’s still so early: We predict agents will search 1000x more than humans by 2030. Agents don't search like humans. They write long, complex queries and want all the world's data, not just the web. We've spent 5 years building a search engine designed for them. We now serve personal agents, AI labs, coding agents, GTM agents, really any agent. Exa gives these agents access to 100s of billions of web documents and tons of proprietary data. Our customers are increasingly noticing that information is the bottleneck to agent performance. While the world seems close to perfect intelligence with models like Fable and Astra, we are very far from perfect information. To our small but legendary team, thank you for getting us here, from engineering to research to GTM to ops. To our customers, it is an honor to serve you. We have some exciting releases coming soon and can't wait to share them 🫡
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launched a model accidentally served trillions of tokens a day 29.4% of the fortune 500 showed up raised a really big series A from @a16z it's been 3 weeks we would like to sleep now
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Jason Cui retweeted
AWS CEO Matt Garman with a16z's Raghu Raghuram on the biggest cloud provider in the world being rebuilt for the agentic era: $220B in CapEx for 2026, two million NVIDIA GPUs on order, AWS's AI chips sold out through next year, and a new 30-second AWS account with no credit card required so agents can get rolling. 0:55 $170B in revenue, growing 37% 2:40 30-40% of revenue started as startups 4:55 Startups want a cloud for agents 9:10 An AWS account in 30 seconds 12:25 Agents don't need bulletproof databases 16:30 Why AWS won't sell every GPU to the frontier labs 22:00 Why Matt isn't worried about a bubble 24:45 Why AWS builds its own power plants 27:45 Planning for the next supply shortage 30:25 Saving one county $5K per resident 33:10 How AWS built its own chips 40:05 What's holding enterprise agents back 45:35 Why Bedrock never sends your data to the model 49:30 AWS's new AI security tool 51:50 Why AWS teams of 10 are now 3-4 YouTube: youtube.com/watch?v=rn_afJaP… @mattsgarman @awscloud @RaghuRaghuram
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a16z is officially in Japan, led by Hitoshi Yoshida as Head of Japan, with the opening of our Japan office. It was an honor welcoming Governor Koike at the opening earlier today. Japan combines world-class industrial capabilities with growing innovation in AI, cybersecurity, robotics, and defense. By bringing our portfolio companies and the Japanese ecosystem together, we aim to accelerate Japan’s AI-native economy and strengthen the ties between Silicon Valley and Japan. As the former President of Microsoft Japan and Hewlett-Packard Japan, Hitoshi brings decades of technology leadership and deep relationships across business, industry, and government. We’re thrilled to have him lead our efforts in Japan and look forward to doing great work in partnership with the Japanese technology community. 日本代表として吉田仁志を迎え、日本オフィスを開設できたことを大変心強く光栄に思います。日本は、世界有数の産業基盤と、AI・サイバーセキュリティ・ロボティクス・防衛などの分野における目覚ましいイノベーションを兼ね備えています。 我々はこれまでになかった機会を、日本の若い世代に提供していくことを目指します。日本のテクノロジーコミュニティの皆様と共に、日本の市場やエコシステムの発展に貢献していけることを楽しみにしています。
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Jason Cui retweeted
Best Edit Model is here by @ideogram_ai It's unfair there are two guys in particular look good in every outfit, including the duck suit.
Introducing Ideogram 4.5, the most precise edit model. With each edit, leading models add artifacts, pixel shifts, and color changes. Ideogram 4.5 eliminates artifact buildup, making multi-turn editing possible. Live in Ideogram, the API, and launch partners. Open weights soon.
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Jason Cui retweeted
jev isn't production ready. today @modaicdev is launching Mo, the first multimodal decision model that learns from its mistakes. most production tasks involve subjective decision-making, where the last mile of calibration and alignment has always fallen on the developer. Mo closes that gap on its own. it refines its instructions and weights from the signals already in your workflow to learn what a good decision means for you. use Mo for the decisions where alpha matters the most like LLM judging, lead scoring and qualification, content moderation, resume screening, and more. if you're already using another decision model like jev, plug it into Modaic and it becomes self-improving too :) 🐙 modaic.dev docs.modaic.dev
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Jason Cui retweeted
Replying to @fal
@fal's H3 Max generates video faster than you can watch it. With director mode and voice prompting, you can direct a scene as it plays - moving the camera and guiding the action just by talking to the model. The leap isn’t just speed. It’s creative control. That’s what takes AI from impressive demos to a serious technology for Hollywood and professional filmmakers. Inspiring convo with @gorkem and @isidentical on what possibilities are unfolding in generative media.
.@fal's Gorkem Yurtseven and Batuhan Taskaya on making an open source video model 35x faster, and what Hollywood wanted after they built it: Last month, MiniMax released H3, an open source video model. fal rebuilt it - they cut down the steps the model takes to make a video, rewrote the code under each stage, and got the GPUs to 70-80% of their theoretical ceiling instead of their usual 30-40%. No quality loss. Video now generates faster than you can film it. The models have gotten so cheap and fast that end users aren't even asking for improvements in either category anymore. The gap has moved to quality, or how closely the model follows the prompt. Hollywood wasn't a customer a year ago and is now fal's fastest growing segment. Studios love it for the little things - extending a shot, moving the camera, changing the lighting. Those edits land 80-90% of the time. fal is chasing 99.9%. In this conversation with a16z's Jennifer Li: 00:00 Intro 01:45 The first open model worth rebuilding 03:45 The industry ran out of compute in April 06:25 35x faster without losing quality 11:05 5s of video generated in 1.5s 14:25 The weekend fal dropped everything 16:15 3 viral projects nobody planned 18:20 Teaching a video model to remember 20:25 An hour of video that's consistent 23:30 2x the usage of other models in 3 weeks 26:35 The case for giving video away for free 29:00 Blender sketch in, finished shot out 30:40 Chasing 99.9% reliability 34:15 Hollywood, fal's fastest-growing customer 36:50 Why studios wouldn't touch it until now YouTube: youtu.be/SDbRJXQrYGY @gorkem @isidentical @fal @JenniferHli
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We’re partnering with @inferact (the team behind @vllm_project) to make TPUs a first-class citizen for open-source AI inference. Together, we’re delivering: - Upstreamed open-source TPU kernels - Native PyTorch integration via TorchTPU + so much more ↓
Replying to @googlecloud
@googlecloud and Inferact are announcing today a partnership to make TPU a first-class citizen in @vllm_project. This partnership puts both teams on one engineering roadmap to bring TPU to the broader open model ecosystem, optimizing vLLM as the agentic production serving engine for TPU: • Production serving features and optimized kernels • A native PyTorch path via TorchTPU • Moving towards day-0 support for frontier model releases We're also launching a community program: shared TPU capacity for open-source contributors, plus dedicated review and design help from the core vLLM maintainers at Inferact. Everything this collaboration produces is open source. Read the full announcement: inferact.ai/news/google-tpu-…
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Jason Cui retweeted
Vals AI co-founder and CEO Rayan Krishnan with a16z's Ben Horowitz and Jennifer Li on grading AI, what it costs, and who gets to make the rules: Every big industry eventually grows an independent testing layer. AI has credit ratings to learn from and Enron to avoid. Model capability today is still mostly self-reported. As public benchmarks saturate and models get better at optimizing for the tests themselves, Rayan makes the case for independent, continuously evolving evaluations. The harder problem is geopolitical. Reagan's "trust but verify" worked during the Cold War because you could fly over and count the missiles. No simple equivalent for AI models exists. In this conversation with Erik Torenberg, they get into how you measure a model's ability to improve itself, why every good benchmark eventually has to be retired, and what happens when token spend begins to rival employee salaries. 00:00 Intro 02:20 Llama 4 on public vs private benchmarks 05:24 Nobody agreed how to test humans either 06:55 What movie ratings teach us about AI 08:55 The Enron problem in benchmarking 11:36 Why a good benchmark has to be retired 13:22 Evals that run for weeks, not seconds 16:20 Where the real workday starts at 4pm 18:08 A firm really is just its evals 20:35 Why Sonnet can cost more than Opus 22:42 One engineer, 6 billion tokens in a day 25:05 Who should set the rules for models 28:55 Public sector enforces, private verifies 33:32 Why sovereign AI is inefficient and happening anyway 35:00 The AI version of trust-but-verify 37:15 Where cyber evals have to go next YouTube: youtube.com/watch?v=WO9c9qxD… @RayanKrishnan @ValsAI @bhorowitz @JenniferHli @eriktorenberg
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Jason Cui retweeted
OpenAI's Mark Sellke and Mehtaab Sawhney with a16z's Lisha Li, on the state of AI and mathematics: Before OpenAI released GPT‑6 Astra last week, the model was already doing original mathematics. Recorded before the launch, this conversation tells the story of how it got there. It began with GPT‑5. Mehtaab Sawhney pasted in an Erdős problem still listed as open. Five minutes later, the model surfaced a paper that had solved it. The exercise eventually uncovered published solutions to 10 more problems thought to be open. Then Astra went further. Told to "go have fun" with a high-dimensional sphere-packing problem, it improved a bound that had stood since the 1970s. Mehtaab had spent six months on the same problem in graduate school and made "absolutely zero progress." Another Astra result established that non-sofic groups exist with a roughly 15-page proof. A related human breakthrough took 250 pages and machinery from quantum complexity theory. OpenAI’s Mark Sellke and Mehtaab Sawhney join a16z’s Lisha Li on why wrong ideas pollute a human’s context window, why polished papers hide how mathematics is actually made, why a breakthrough can stop one prompt early, and what math rewards once proving stops being the bottleneck. 00:00 Intro 02:44 Cracking an Erdős problem in 5 minutes 06:20 Why a human quits and a model doesn't 08:50 Wrong ideas pollute your context window 11:45 Why math papers are bad training data 16:20 Nobody knows how to stack spheres in high dimensions 18:28 The orange-stacking proof 21:04 The 1970s Russian paper nobody could beat 24:14 The function that won a Fields Medal 27:09 How Astra beat the sphere-stacking record 29:20 Why error correction is sphere packing in disguise 35:15 The breakthrough Astra almost didn't bother with 39:22 Solving harder problems means it has better taste 41:00 One model for taste, one for the grind 44:40 Astra found an infinite group no finite one can imitate 52:00 250 pages of quantum complexity, or 15 of group theory 56:18 Only humans write 200-page proofs 1:00:38 What changes when proving stops being the bottleneck 1:02:44 The problems AI may never solve YouTube: youtube.com/watch?v=1JvyLGd2… @mehtaab_sawhney @MarkSellke @OpenAI @lishali88
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Jason Cui retweeted
We're thrilled to lead a $300M investment in Gimlet Labs. AI inference is one of the fastest-growing markets in the history of capitalism, and we are running out of nearly every physical input required to serve it. Inference demand compounds at software speed; power plants, data centers, and semiconductor fabs do not. We believe @gimletlabs has built the solution: the first multi-silicon inference cloud, designed to produce more intelligence from every watt. This system is already delivering up to 10x gains in throughput and interactivity on frontier models within the same power envelope. In a market starved for compute, efficiency is net-new capacity and latency is product differentiation. Wherever the existing stack ends, the Gimlet team starts. Welcome, @zainasgar, Michelle Nguyen, @oazizi, @nserrino, James Bartlett, and the Gimlet Labs team! By @RaghuRaghuram, @sarahdingwang, @shangdaxu, @steph_zhang
1/ Today, we announced Gimlet Labs’ $300M Series B, led by @a16z, joined by @SapphireVC as a major investor bringing our valuation to $3B. We started Gimlet with a simple conviction: inference would become the dominant AI workload, and its infrastructure would need to be rebuilt from the ground up.
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