K-Scale Labs

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K-Scale Labs, Inc. was an American robotics startup, founded in 2024, that developed open-source humanoid robots. Based in Palo Alto, California, the company was backed by Y Combinator and positioned itself as a builder of affordable, hackable humanoid platforms for developers, researchers, and hobbyists. K-Scale shut down in November 2025 after failing to secure a lead investor for its Series A, having shipped only two units of its flagship K-Bot before ceasing operations. Upon closing, the company released all remaining proprietary hardware and software under open-source licenses.^[1][2][3]

K-Scale is often cited as the most prominent attempt to build an "Android for the real world," a low-cost, broadly accessible humanoid platform. Its failure also became a widely discussed case study in running a hardware company on software-startup economics, especially in a global humanoid market dominated by rapid Chinese price cuts from firms such as Unitree.^[4][5]

History

Founding and early development

K-Scale Labs was founded in 2024 by Benjamin Bolte, a former senior engineer at Tesla who wrote the CUDA code for the voxel occupancy network behind the Tesla Optimus perception model, and later worked on Meta's AI research team on robotics foundation models and semantic mapping. Co-founders included Matthew Freed (advanced robotics at Lockheed Martin and General Dynamics); Pawel Budzianowski, the software lead, a machine learning researcher with a Ph.D. in dialogue systems from the University of Cambridge and prior experience as ML lead at PolyAI; and Willem Van Rijswijk, who handled hardware and operations.^[6][7]

The name referenced the Kardashev Scale, an astrophysics framework introduced by Soviet astrophysicist Nikolai Kardashev in 1964 that measures a civilization's technological advancement by energy consumption. Bolte described the mission in expansive terms: "We're building the infrastructure to make humanity into a Type I Kardashev civilization, and we're making it open source."^[7][8]

K-Scale started in a Palo Alto garage with roughly nine people, joined Y Combinator's Winter 2024 batch (W24), and used the three-month accelerator to ship its first hardware iteration, the Stompy prototype.

How much funding did K-Scale Labs raise?

K-Scale raised an initial $500,000 in pre-seed from Lombardstreet Ventures and Y Combinator, then approximately $4 million in a seed round at a roughly $50 million valuation in February 2025. Reported backers included GFT Ventures, Pioneer Fund, AI Grant, Lux Capital, Fellows Fund, and angels Nat Friedman and Daniel Gross. Total publicly reported funding sat around $4 million to $4.75 million.^[3][5][9]

OpenAI's nonprofit arm donated $250,000 to K-Scale's open-source work, and OpenAI CEO Sam Altman was reported to have pre-ordered a K-Bot. In June 2025, a subsidiary of Chinese vehicle manufacturer Zhejiang Taotao Vehicle Industry (Tao Motors) invested approximately $2 million and committed supply chain support, including manufacturing capacity in Texas. Even with those contributions, K-Scale never raised a Series A.^[3][10]

Stompy prototype

Before K-Bot, K-Scale built an early prototype called Stompy (Zeroth-01), introduced in February 2024. It was a 122 cm tall, fully 3D-printable humanoid with a bill of materials under $10,000. The team produced five hardware iterations over three months during the YC batch. Every part was sized to fit on a standard 256 x 256 mm 3D printer bed, and all CAD files, assembly guides, and bills of materials were made public. Stompy used quasi-direct drive actuators with 6:1 to 8:1 reduction ratios, providing back-drivable, low-inertia joints with peak torques of roughly 3 to 12 Nm. Power came from a 48V 15Ah hot-swappable battery good for over an hour of runtime.^[11][12]

Stompy was one of the first credible "garage-built" humanoid robots and validated the thesis that meaningful humanoid research could happen outside well-capitalized industrial labs.^[11]

K-Bot launch and shutdown

K-Scale opened K-Bot pre-orders in summer 2025 at $8,999 for the first 100 Founder's Edition buyers. Pre-orders eventually totaled over $2 million from more than 100 customers, including engineers at OpenAI, Nvidia, and Amazon. The first units shipped in October 2025.

On November 4, 2025, Bolte sent a letter to investors and customers announcing that K-Scale was winding down. The company had less than one month of runway and roughly $400,000 in cash. Acquisition talks with 1X Technologies and The Bot Company collapsed after both signaled interest in acqui-hiring select engineers rather than acquiring K-Scale outright. Only two K-Bot units shipped before remaining pre-order deposits were refunded and most of the ten-person team was laid off. In the letter, Bolte wrote that "I have not been able to find a lead investor," and explained that without enough capital for tooling and regulatory approvals, "the unit economics for our product do not make sense." He announced that all remaining IP would be released under open-source licenses, framed as an attempt to "lay the foundation for future hackers and dreamers."^[1][2][13]

Why did K-Scale Labs fail?

A widely circulated post-mortem by Rui Xu, K-Scale's former chief operating officer and a hardware veteran of Intel, Xiaomi, Lenovo, Amazon, and ByteDance, identified several strategic errors:^[14][21]

1. Treating supply chain as a procurement task rather than a core competency. Negotiating separately with multiple Chinese contract manufacturers meant unit costs could swing from $800 to $2,400 per robot.
2. Spending months on locomotion problems while competitors shipped demos, missing the fundraising window.
3. "Large model chauvinism," relying on AI to compensate for hardware deficiencies. The team debated treating mechanical safety features like joint end stops as optional, assuming learned policies could prevent damage.
4. Weekly engineering deadlines that strained relationships with manufacturers needing reliable schedules to allocate factory capacity.
5. Underweighting mechanical reliability relative to peers like Figure AI and Tesla.
6. A Series A funding gap the company could not close before runway ran out.

Xu framed the safety stakes of the "large model chauvinism" mistake bluntly: "When a language model hallucinates, you get a wrong answer. When an actuator blows past its joint limit at full torque because the policy had one bad inference step, you get a broken machine. Or a broken person."^[21]

In a podcast after the shutdown, Bolte called the decision to launch the expensive K-Bot ahead of the cheaper Z-Bot his single biggest misstep. A VC had told him that 100 K-Bot pre-orders would unlock a $20 million Series A; that did not happen. "I kind of had bet the farm on the K-Bot launch," he said, adding that he hesitated to lead with Z-Bot because he wanted K-Scale taken seriously as a humanoid company rather than a toy maker.^[15]

The macro context did not help. When K-Scale launched its $8,999 K-Bot, comparable U.S. humanoid hardware typically cost $50,000 or more. By late 2025, Unitree was selling its G1 humanoid in the U.S. for about $20,000, and Songyan Power had introduced the first sub-10,000 yuan humanoid in China, intensifying a global price war that compressed margins faster than any new American entrant could absorb.^[5]

Products

K-Scale built three humanoid hardware platforms, all designed to be fully open in hardware and software with publicly available CAD files, bills of materials, and assembly guides. A fourth, mid-size model called the M-Bot, roughly 70 cm tall and priced under $3,000 for early buyers, was announced but never shipped before the company closed.^[7]

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K-Bot specifications

The K-Bot was K-Scale's flagship and the product the company staked its survival on. It used commercial off-the-shelf (COTS) components to keep cost roughly 60% below earlier $50,000+ research humanoids while still delivering 20 degrees of freedom and useful payload capacity.

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The K-Bot also offered an optional "Full Autonomy" upgrade path: K-Scale committed to deliver free hardware and software improvements until customers' robots could operate with less than one human intervention per day, targeting June 2028 for that milestone.^[16]

Z-Bot (Zeroth Bot)

The Z-Bot, sometimes branded as the Zeroth Bot, was a roughly 46 cm tall desktop-scale humanoid for students, classrooms, and hackers. It came out of a K-Scale hackathon and reached a working prototype in about two months. Buyers could pre-order an assembled unit for around $999 or a DIY kit starting at $350. Despite its size the Z-Bot supported RL-based walking, basic vision and audio, and torque-controlled joints. K-Scale launched it on Kickstarter in early 2025; after the closure Bolte cited the decision to lead with K-Bot instead of Z-Bot as a key strategic mistake.^[15][17]

Stompy (Zeroth-01)

Stompy was the precursor to both later robots and remains historically significant as the first fully open-source, 3D-printable humanoid a small team could assemble in a garage. Several independent developers built their own units after the design dropped.^[11]

Technology

K-Scale Labs built an unusually broad open-source software stack. Most of it is preserved on the company's GitHub organization, github.com/kscalelabs, which by late 2025 hosted more than 130 repositories spanning firmware, simulation, learning, inference, and teleoperation.^[18]

Software stack

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K-Scale was unusual in choosing to skip ROS entirely. The team built its control stack in Rust to get deterministic real-time performance and avoid the operational overhead of ROS. K-Sim, the RL library at the heart of the training pipeline, was reported to generate more than 100,000 training samples per second using MuJoCo MJX on JAX, making large sim-to-real policy training tractable on modest hardware.^[19]

EdgeVLA, K-Scale's vision-language-action model, ran on-device on the Raspberry Pi 5. It took voice and visual input and emitted action tokens, giving the K-Bot a foundation for natural-language task execution without a cloud round-trip.

Open-source licensing

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At shutdown, Bolte committed the company's remaining IP to non-commercial open-source licenses so the work could continue outside the company. Hardware was released under the CERN Open Hardware License Strongly Reciprocal v2 (CERN-OHL-S-2.0), which requires derivative hardware to remain open. Most software stayed on MIT or compatible licenses.^[2]

Community

At its peak the K-Scale Discord had more than 2,000 active members. The company ran public hackathons under the K-Hacks brand, including K-Hacks 0.1, which produced the Zeroth-01 design. K-Scale also published Hugging Face datasets and trained weights, making it one of the few humanoid efforts that exposed both training code and trained policies publicly.

Why was K-Scale Labs open source?

Open source was central to Bolte's argument for why a humanoid company should exist at all. He argued that "the only way for humanoid robots to achieve mass adoption is by being open-source, auditable, and broadly accessible," and on the YC Hacker News launch thread he wrote that he would not personally trust a humanoid robot in his home if its software were not auditable.^[7] The company's materials framed humanoids as something to be "shared by everyone" rather than controlled by a handful of well-capitalized labs.

Every hardware revision shipped with full CAD source and a public bill of materials. Firmware and the operating system were open from day one. When the company closed, the open-source posture meant the shutdown did not erase the work: independent developers, university labs, and the successor company Gradient Robotics could continue iterating without any IP unwind.

Not everyone was convinced. Hacker News commenters compared the K-Bot to lower-cost academic platforms like Berkeley Humanoid Lite (around $5,000) and raised concerns about military weaponization, given that open hardware can be modified for any purpose. Bolte engaged directly, arguing that an open ecosystem was safer than a closed one in the long run.^[20]

Legacy

What is Gradient Robotics?

After the closure, former K-Scale engineers Jingxiang Mo (JX Mo) and Scott Carlson, K-Scale's head of engineering, established Gradient Robotics in Menlo Park, California. Backed by early-stage community South Park Commons, Gradient describes itself as building "American-made humanoid robots designed for general-purpose physical work" and pitches itself as the "open-source Unitree for America." Mo said the team had "inherited the K-Scale spirit, mission, and core engineering team," closed a pre-seed round in September 2025, and was "accelerating fast." Bolte was not part of the new company, telling interviewers he was "mostly decompressing."^[13][15][22]

K-Scale's run became a reference point in the debate about whether a Western company can compete on price with Chinese humanoid manufacturers without massive upfront capital. The company shipped only two flagship units, yet its software stack, design files, and post-mortem material continue to circulate as a starter kit for anyone building an open humanoid platform. It is also cited as a cautionary case on hardware-versus-software economics: pre-orders did not equal product-market fit, open source did not translate into margin, and a "bet the farm" launch left no fallback when the Series A did not close.

See also

• K-Bot
• Humanoid robots
• Open-source hardware
• Y Combinator
• Sim-to-real
• Vision-language-action model
• Unitree
• Figure AI
• 1X Technologies
• Tesla Optimus

References

1. "Palo Alto Humanoid Startup K-Scale Labs Shuts Down." Mike Kalil, November 2025. ↩
2. "K-Scale Labs Cancels K-Bot Orders, Open-Sources All IP After Funding Fails." Humanoids Daily, November 4, 2025. ↩
3. "K-Scale Labs Funding, Financials, Valuation & Investors." Crunchbase. ↩
4. "K-Scale Labs Shuts Down Amid Fierce Global Price War." Six Degrees of Robotics. ↩
5. "The First Humanoid Robot Company Collapses During Mass Production." 36Kr (English edition), 2025. ↩
6. "K-Scale Labs: Open-source humanoid robots." Y Combinator company profile. ↩
7. "K-Scale Labs Disrupts Silicon Valley with Open-Source Humanoids." Mike Kalil. ↩
8. "K-Scale Labs: Betting on Open Source for the Future of Humanoid Robotics." Humanoids Daily. ↩
9. "K-Scale Labs 2026 Company Profile: Valuation, Funding & Investors." PitchBook. ↩
10. "K-Scale Labs Stock Price, Funding, Valuation, Revenue & Financial Statements." CB Insights. ↩
11. "World's first garage-built humanoid robot open to creators worldwide." Interesting Engineering. ↩
12. "Zeroth-01 - Introduction." K-Scale Docs. ↩
13. "Former K-Scale Team Launches 'Unitree for America'." Mike Kalil. ↩
14. "Why K-Scale Labs Failed: 6 Hard Lessons from Inside." There's a Robot for That. ↩
15. "K-Scale Labs CEO Explains Shutdown: 'I Bet the Farm on the K-Bot Launch.'" Humanoids Daily, November 2025. ↩
16. "Launch HN: K-Scale Labs (YC W24) - Open-Source Humanoid Robots." Hacker News, 2025. ↩
17. "Zeroth Bot: The Programmable Humanoid Robot." Kickstarter. ↩
18. "kscalelabs." GitHub organization page. ↩
19. "kscalelabs/ksim." GitHub. ↩
20. "K-Scale Labs: Open-source humanoid robots, built for developers." Hacker News discussion. ↩
21. "6 Lessons I Learned Watching a Robotics Startup Die From the Inside." Rui Xu, The Robot Report, March 2, 2026. ↩
22. "Gradient Robotics." South Park Commons company profile. ↩