Kimi-K3 Technical Report [pdf]

(github.com)

253 points | by vinhnx 2 hours ago ago

71 comments

  • GodelNumbering 22 minutes ago

    Back of the envelope calculation (could be off, correct me if I am)

    If you are a large enough company that spends million+ on inference a month, it makes sense to buy a GB300 rack ($6M on top range from what I could find) which has 20.7 TB. Since the model is mixed trained (MXFP4), you would need less than 10% of the rack's memory to serve the full model. Aggregate HBM bandwidth: 576 TB/s. You can run over 6000 parallel agentic workflows (each with ~100k context on average) at ~30 tok/s.

    Assuming the annual amortization+electricity at $1.5M/year and about 50% average annual utilization, you get less than 60 cents (USD) per million output token, for a frontier model with plenty of capacity to share, all your data never leaving premises and well over an order of magnitude cheaper!

    As long as a company believes that the openweight models will continue to get more capable and 'AI is here to stay', this model provides the first solid footing for a decision to just buy a rack.

    • 999900000999 10 minutes ago

      And hire 2 or 3 dev ops to keep it running ?

      That another 400 to 700k.

      It becomes your problem and not someone else’s. However, I don’t trust hosted LLMs for anything that needs to be private.

      • lumost 2 minutes ago

        There will be cloud/SaaS vendors who have lower cost of labor/capital due to automation and financing terms.

        Having these models in the open caps the inference margin.

      • wongarsu 5 minutes ago

        Where do I sign up to get 200k/yr to keep one rack running? Sounds like an incredibly chill job

        • arjie 2 minutes ago

          Apparently it’s going to take the 3 of us to do this, mate. Going to get so much reading done.

      • russell_h 8 minutes ago

        > However, I don’t trust hosted LLMs for anything that needs to be private.

        Why not? Do you trust AWS with things that need to be private?

        • Kevcmk 2 minutes ago

          More than I trust frontier labs. AWS doesn't need to recoup 9 digits USD of capex

      • GodelNumbering 4 minutes ago

        > And hire 2 or 3 dev ops to keep it running

        Not a devops but I'd say one full time is already too many.

      • clint 8 minutes ago

        Just let it manage itself, what could go wrong! :)

    • reckless 10 minutes ago

      I think the licensing that would likely apply to a company that's able to afford ~$6M rack and the associated infrastructure muddies this somewhat

      • vidarh 2 minutes ago

        As far as I can tell, license fees are only applicable if you have more than 20m USD/month revenue from services provided using the model, or serve more than 100m users.

  • m_ke an hour ago

    Also open sourced a bunch of infra to go with it.

    Anyone who claims open source and open weights models are "decel" needs to get their head checked

    https://github.com/MoonshotAI/MoonEP

    https://github.com/kvcache-ai/AgentEnv

    https://github.com/MoonshotAI/FlashKDA

    • vanuatu 14 minutes ago

      To me its clear that it is decel

      the only reason other labs can catch up is because the frontier labs can be distilled, and they siphon a % of the labs' revenue to reinvest into the next iteration

      full accel would mean nationalizing the big 2 labs and locking in manhattan project style until RSI

      • m_ke 5 minutes ago

        only if you only get your news from main stream business press and Big Lab propaganda channels

        There's no chance K3 is a distill of Fable, it came out way too soon after the limited fable release to be feasbile.

        If you look at all of the top ML conferences, chinese labs contribute way more to advances in ML than "Open"AI and Anthropic: https://www.reddit.com/r/TheMachineGod/comments/1pi4q7f/pape...

        This K3 release just helped every other lab on the planet stay in the race by making it possible for them to build on top of it, placing them at the frontier starting line instead of having to spend billions of their own dollars and risking it all to attempt to catch up.

        The open source contributions I linked to above will move the whole field forward and reduce the costs of training and inference for everyone.

        Open science compounds on it self, every new advancement pushes the field forwards and opens up new grounds for future improvements.

    • jvanderbot an hour ago

      This comment would be much better without the second line

      • ike_a an hour ago

        I'm not sure I understand the case for open-source models being decelerationist, is this it?

        Decel:

        - Potentially reduces investor appetite for funding big labs.

        - More risk of powerful AI getting in bad hands -> more regulation.

        Accel:

        - More competition so big labs can't rest on laurels.

        - More research in open, so all labs can accrete advancements faster.

        I feel like open-source = acceleration has a much more clear argument. (and how bad would deceleration be in any case?)

        • sosodev 33 minutes ago

          I think the argument is that decentralization leads to deceleration because it means less centralized funding and data. Those are the two primary ingredients for accel.

          The problem with the decel/accel rhetoric is that it lacks nuance.

        • Smaug123 17 minutes ago

          If your worldview is “most of the progress is made by closed labs, then open labs fast-follow” (which isn’t implausible given the documented distillation of Fable), and further that open labs cannot make make meaningful progress vs the closed labs except by fast-following and that they won’t pick up the ability to make progress after the closed labs are gone, then driving closed labs out of business slows down overall progress.

          • reissbaker 2 minutes ago

            I think it's pretty hard to hold that worldview: Anthropic couldn't ship a reasoning model until they copied DeepSeek R1's homework, and they've all copied DS-style super-sparse MoEs at this point too.

        • StevenWaterman an hour ago

          I think it's basically open weights => more inference competition => less profit from inference => less training competition

          • f311a 44 minutes ago

            > less training competition

            I think you meant less research and experiments in big labs because they don't get all the AI money.

            Training is expensive, but they also have more than 10 000 of employees combined and they cost a lot of money.

        • Iolaum an hour ago

          Open Source models decelerate growth of closed AI. For people who think (or want) AI = closed_AI then that argument has weight. Good luck getting them to update their priors.

        • zozbot234 an hour ago

          Open source AI is actually a lot less "powerful" than genuine frontier models, i.e. it has a much tighter inherent capability ceiling. This is "decelerationist" from a purely AGI-pilled point of view but it's actually great if you're worried about a capabilities arms race putting AI Safety at severe risk.

          Kimi K3 is plausibly a lot less dangerous than a totally jailbroken ChatGPT/Gemini/Claude Sonnet (let alone Opus or Fable!) and it's quite deeply weird how no one seems to be calling for those models to be banned or restrained by further regulation. Why the double standard against the less concerning (but more efficient!) open weight models?

          • ike_a 33 minutes ago

            Do you think they are inherently less powerful? I'd imagined that closed labs have a head start / more funding so the open labs are playing catch-up.

            Is there a world where open source models end up at the frontier, or do you think there are structural/first-principles reasons why this won't happen?

            • zozbot234 28 minutes ago

              If you're targeting widespread local/on prem deployment which is what many open weight models are doing, that inherently limits your scale in terms of total model weights/inference-time compute compared to running in a few centralized datacenters. A centralized model will always be able to leverage a larger scale of deployment, placing it much closer to the genuine "frontier".

      • SirLordBoss 16 minutes ago

        Why? Absolutely correct, especially considering the position of the person they're referring to

      • viccis 31 minutes ago

        I know it's a hard ask on this site, but I need you to start parsing content and not tone. It was a helpful bit of context, even if it was a bit vitriolic.

        • Almondsetat 29 minutes ago

          Why should I waste time parsing content and not tone? Why can't the commenter just avoid the tone? It even saves time since you can write less!

      • acedTrex an hour ago

        Why?

  • fahrradflucht an hour ago

    License: https://huggingface.co/moonshotai/Kimi-K3/blob/main/LICENSE

    > If the Licensee or any of its affiliates operates a Model as a Service business, and the aggregate revenue of the Licensee and its affiliates exceeds 20 million US dollars (or the equivalent in other currencies) in total over any consecutive 12 months, the Licensee must enter into a separate agreement with Moonshot AI before using the Software or its derivative works for any commercial purpose.

    + the existing 100 million monthly active users, or more than 20 million US dollars for commercial products have to name Kimi clause

    • simonw an hour ago

      Kimi 2.6 had the same janky license: https://huggingface.co/moonshotai/Kimi-K2.6/blob/main/LICENS... - looks like they've been doing that at least as far back as K2.

      The models they released in 2025 - https://huggingface.co/moonshotai/models - were clean MIT. They started doing the "modified MIT" thing in January 2026 with moonshotai/Kimi-K2-Thinking

      • zozbot234 41 minutes ago

        To be clear, the restriction on "Model as a Service" past $20M yearly revenue is new to K3. K2.x had the attribution requirement for any commercial use with more than $20M monthly revenue.

        • simonw 40 minutes ago

          Good catch, thanks.

      • lossolo 20 minutes ago

        In what way was the license "janky"? Moonshot isn't a trillion dollar US behemoth. If these terms allow it to release near frontier models with open weights, so startups and anyone with enough hardware can use them, while charging only companies with more than $20 million in revenue or 100 million users, that seems like a reasonable trade off.

        • simonw a minute ago

          I use the term "janky" for any time someone releases something under a supposedly open source license that doesn't comply with the OSI definition.

          "Modified MIT" is the perfect example of that.

          I'm not saying it's unreasonable, or that you can't release under such a license - it's your software, use whatever license you like!

          I'll call it "janky" when you do.

        • bilbo0s 6 minutes ago

          Reasonable for people at the bottom of the tech pyramid. Certainly for startup guys this is heaven sent.

          For people at the top of the tech pyramid, I could totally see why they'd want to put an end to all this "Open Source LLM" stuff.

    • throwaway27448 an hour ago

      I wonder how they'll figure out who to target for litigation when this license is violated.

      • paxys an hour ago

        How many companies host and serve models via API and have a $20M+ revenue? Going to be pretty straightforward to catch offenders.

      • bityard 23 minutes ago

        Software licenses aren't enforced through litigation as much as they are enforced through the _threat_ of litigation and legal risk. In other words, pretty much every company pays lawyers to minimize legal risk. Those lawyers inevitably look at all the contracts, agreements, and software licenses, and tell the C-suite what to do in order to keep their legal exposure as low as possible. "Don't violate other companies' IP," is pretty low-hanging fruit in those conversations.

        It is a very rare (and ballsy, and perhaps incompetent) company that ignores their lawyers' recommendations to adhere to the letter of all of the software licenses they are bound to.

      • ffsm8 an hour ago

        They haven't litigated the last public non-compliance... Despite that one being extremely public. So probably not at all for now.

    • embedding-shape 43 minutes ago

      Hah, so much for "open weights" :D Fair enough, they're at least downloadable, shame they didn't end up being actually open, nor open source, the community had really high hopes for this. But again, still available for download, so better than nothing else I suppose.

      • jhonof 39 minutes ago

        Open source projects frequently have separate commercial licenses no? This isn't abnormal.

        • embedding-shape 36 minutes ago

          No, I don't know a single project I'd call "open source" (as understood by the FOSS community) that restricts what you can do with it, that'd make it very much "not open source" as you're discriminating against specific persons/groups/fields of endeavor.

          • parodysbird 29 minutes ago

            GPL licenses also restrict what you can do with it...

            • embedding-shape 24 minutes ago

              Beyond reciprocity which is the entire point of that license, what restrictions does it come with? I guess you could say that it has a restriction of adding new restrictions, but surely that's not what you're talking about?

  • eamag an hour ago

    > we build a self-evolving, hierarchically organized knowledge graph that agents continuously expand through web-scale exploration across knowledge-intensive and coding domains

    That's interesting!

  • whimsicalism an hour ago

    It's funny that we've finally returned to tanh activation functions, time is a circle.

    • pinkmuffinere 18 minutes ago

      Wow this is fascinating enough that I’m actually going to read tfa lol

  • a-dub an hour ago

    knowledge graph guided task synthesis. very cool! i have long wondered about the "how do you get good coverage of all the tasks" problem.

    maybe some interesting theoretical work there around the rate of production of new knowledge itself and various mechanisms (human approaches, mechanistic approaches, etc).

  • storus an hour ago

    What would be the current best method to fine-tune it for my own specific agentic tasks? LoRA + DPO? GRPO? Something else?

    • whimsicalism an hour ago

      LoRA + SFT, but it'll be big - better to wait for a finetuning API from one of the providers, I wouldn't jump straight to RL or off-policy pseudo-RL like DPO.

  • weberer 25 minutes ago

    Does anyone know if a torrent is available? I think it would take quite a while to download 1.5tb from their servers.

  • eamag an hour ago

    Can someone explain what are teachers in Multi-Teacher On-Policy Distillation? I can imagine math, coding and other verifiable domains, but they also have biology? Is it where distillation from bigger models come in?

  • lenerdenator an hour ago

    What would it take to get an American open model to compete with this?

    • embedding-shape 40 minutes ago

      Latest "big" release from any of the bigger American lab must have been GPT-OSS-120b I think? Released ~summer 2025, so pretty much two years ago. Doesn't seem like it'll happen by itself, so something either forcing their hand figuratively, or something forcing their hand literally.

      Personally I was wishing/hoping for one of the recent Gemma releases to be in the ~100B class at least, but sadly Google is keeping that all for themselves.

      • Stagnant 8 minutes ago

        NVIDIA-Nemotron-3-Ultra-550B-A55B was released in June 4th 2026 and I think it was the largest open US model until thinking machine's Inkling (975B) was released a couple of weeks ago.

      • whimsicalism 5 minutes ago

        the longer i read this comment the wronger it gets

      • layer8 33 minutes ago

        August 2025.

      • lossolo 15 minutes ago

        Yeah, besides that, the only big other open source US model that was worth looking at was Inkling (975B params), Jul 15, 2026.

        https://thinkingmachines.ai/news/introducing-inkling/

    • segmondy 26 minutes ago

      if it's to be believed, it's so easy. you distill it, and you have a copy in 2 weeks, isn't that what China is doing? so 2 weeks from now, we should have one.

    • boomskats an hour ago

      An act of G̶o̶d̶ Congress?

    • chrsw 43 minutes ago

      Something beyond my imagination

  • colesantiago an hour ago

    This is amazing to witness. Moonshot open sourcing Kimi K3, a frontier AI and other components really means we are getting abundant AI for all of humanity.

    Kudos to Moonshot for truly being what OpenAI should have been.

    Fable-level and frontier AI should be open source and available to everyone for free.

    • embedding-shape 39 minutes ago

      > Kudos to Moonshot for truly being what OpenAI should have been.

      Kudos to Moonshot for making these weights available for download. Lets not fool ourselves and claim these are "open source" by any understanding of the concept though, there are usage restrictions (even if you download them) and also training data isn't clearly broken down either, nor it it actually using a FOSS license.

      • lossolo 6 minutes ago

        > Kudos to Moonshot for making these weights available for download. Lets not fool ourselves and claim these are "open source" by any understanding of the concept though, there are usage restrictions (even if you download them) and also training data isn't clearly broken down either, nor it it actually using a FOSS license.

        They will probably never release the training data because that represents a large part of their competitive moat. The same is true of US companies (Google, OpenAI, Meta etc) none of which has released the full training data for its open models.

        They use private datasets that cost a lot to acquire, synthetic datasets and a lot copyrighted material for which they don't have licensing.

        What matters most is that, with the necessary hardware, I can download a near frontier model, run it and modify it however I want. The other concerns you mentioned are just noise. And if my company is generating $20 million in revenue or serving 100 million users, it can probably afford a relatively inexpensive commercial license.

  • brcmthrowaway 37 minutes ago

    Is this p-hacking?

  • m00dy an hour ago

    I would want to see three things before drawing strong conclusions:

    End-to-end tokens/sec and cost on realistic coding agent trajectories, including tool outputs and retries, not isolated decode benchmarks.

    Cache hit rates and prefill cost for branching, multi-turn sessions.

    Router-load distributions after post-training, where expert collapse or specialization problems often show up.