Organization
LMSYS (Large Model Systems Organization)
LMSYS (Large Model Systems Organization) is a research lab and nonprofit research organization. This catalog lists 1 software project from LMSYS (Large Model Systems Organization), under licenses including the Apache License 2.0.
Documented roles: Research lab · Nonprofit research · Open-source steward
LMSYS is a 501(c)(3) nonprofit that incubates open-source AI projects and research. It began in 2023 as a collaboration among UC Berkeley, Stanford, UC San Diego, Carnegie Mellon, and MBZUAI, and was incorporated as a nonprofit in September 2024. Its projects include the SGLang serving engine, FastChat, RouteLLM, and the Vicuna models.12
Status: Chatbot Arena, formerly an LMSYS project, moved to its own site in September 2024, and LMSYS now lists it as graduated. Arena Intelligence Inc., a separate company formed in 2025, operates the platform, now called Arena. LMSYS says it continues as an incubator for new projects.516
Using this organization’s offerings
The detailed audience, self-hosting, pricing, and restrictions review has not yet been completed. Consult the sourced product records below and the publisher’s current terms. Missing detail means unknown, not unavailable.
Key facts
- Ownership (separate from openness)
- Nonprofit
Recorded classification; fact-level ownership verification pending.
- Legal form
- Corporation recognized by the IRS as tax-exempt under Section 501(c)(3); LMSYS describes itself as a 501(c)(3) nonprofit incorporated in September 2024.341
- Headquarters
- Not documented
- Founded
- Unknown
- Sectors
- Research, Open models
What is and isn’t public
Products
No product records yet.
Cataloged artifacts
Runtimes
- SGLangSoftwareAvailability: Public
Notable documented facts
- The SGLang repository states that the project is currently hosted under LMSYS.7
- A July 2026 post on the LMSYS blog, credited to RadixArk and Google, states that RadixArk, a company, is a maintainer of the SGLang project. RadixArk's website says the company builds on SGLang for inference and will keep investing in it.910
In the news
SGLang 0.5.22 adds Apple Silicon support with the PyTorch backend and an InstantTensor loader
The SGLang project published v0.5.22 on GitHub on October 19, 2026. The release notes say SGLang now runs on Apple Silicon Macs with the standard PyTorch backend, alongside MLX, that a new InstantTensor loader speeds up model loading, and that HiSparse now supports EAGLE and MTP for long-context serving with the KV cache in CPU memory. Newly supported models listed include Clef / Clef Flash, PPLX-Decider v1 / v1.1, EmbeddingGemma 2, Kandinsky 6 and SANA-Video 2.0. The notes say SGLang now requires Python 3.11 or newer, and describe a fix for hybrid linear models that could resume from wrong mamba states when speculative decoding and structured output were used together. USASI has not tested these changes.
SGLang 0.5.21 adds a Decisions API and runtime prefill-decode role switching
The SGLang project published v0.5.21 on GitHub on October 2, 2026. The release notes highlight prefill-decode instances that can switch between prefill and decode without a restart, a Rust core for the prefix cache by default, a new Decisions API (
/v1/decisions) that lets an LLM or VLM act as a low-latency classifier and scorer, and a Score API (/v1/score) that scores all candidates in one request. Under breaking changes, request-suppliedchat_templatevalues are rejected unless the server starts with--trust-request-chat-template, and deprecated endpoints, environment variables, and aliases, along with legacy radix cache implementations, were removed. The release also adds support for models including DeepSeek-V4.1 Flash and MiMo-V2.6. USASI has not tested these changes.
What this catalog does not know
- Founding date: not documented in the sources reviewed.
- Headquarters: not documented in the sources reviewed.
- Official careers page: not verified by this catalog.
- Products: none documented in this record.
Have a primary source? How to report a correction.
U.S. eligibility
Eligible · basis: U.S. nonprofit or lab
LMSYS's about page names the organization Large Model Systems (LMSYS Corp.) and states that it is a 501(c)(3) nonprofit, incorporated as a nonprofit in September 2024. The IRS exempt-organization extract for California lists LMSYS Corp, with a Sacramento, California address, as a 501(c)(3) corporation with a September 2024 ruling date. No LMSYS page states a headquarters address, so the headquarters field is left empty.134
Sources
This listing is not an endorsement or a federal approval.
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APA style
USASI. (2026, September 29). LMSYS (Large Model Systems Organization). United States of America Superintelligence. https://unitedstatesofamericasuperintelligence.com/companies/lmsys/
BibTeX
@misc{usasi_lmsys,
author = {{USASI}},
title = {LMSYS (Large Model Systems Organization)},
year = {2026},
month = sep,
howpublished = {\url{https://unitedstatesofamericasuperintelligence.com/companies/lmsys/}},
note = {United States of America Superintelligence. Last updated 2026-09-29}
}The date is when this page was last updated. Add the date you read it if your style needs one.
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