--- title: "uqlm vs FastChat" type: "comparison" canonical_url: "https://www.graphcanon.com/compare/cvs-health-uqlm-vs-lm-sys-fastchat" tools: ["cvs-health-uqlm", "lm-sys-fastchat"] --- # uqlm vs FastChat *GraphCanon updated Jul 11, 2026* ## Verdict Pick uqlm when tags unique to uqlm: ai evaluation, ai-safety, confidence-estimation, confidence-score; pick FastChat when tags unique to FastChat: chatbots, distributed serving, evaluation system, large-language-models. [uqlm](https://cvs-health.github.io/uqlm/latest/index.html) reports 1.2k GitHub stars, 126 forks, and 23 open issues, last pushed Jul 9, 2026. [FastChat](https://github.com/lm-sys/FastChat) has 39k stars, 4.8k forks, and 1.0k open issues, last pushed May 1, 2026. Figures are from public GitHub metadata via [uqlm's repository](https://github.com/cvs-health/uqlm) and [FastChat's repository](https://github.com/lm-sys/FastChat). | | [uqlm](/tools/cvs-health-uqlm.md) | [FastChat](/tools/lm-sys-fastchat.md) | | --- | --- | --- | | Tagline | UQLM: Uncertainty Quantification for Language Models, is a Python package for UQ-based LLM hallucination detection | An open platform for training, serving, and evaluating large language models | | Stars | 1,183 | 39,490 | | Forks | 126 | 4,788 | | Open issues | 23 | 1,027 | | Language | Python | Python | | Adopt for | - | FastChat is a comprehensive open platform for managing large language models (LLMs) that includes capabilities for training, serving, evaluating, and comparing chatbot models via web UIs and RESTful APIs. It powers ChatB | | Persona | - | - | | Runtime | - | - | | License | Apache-2.0 | Apache-2.0 | | Categories | Computer Vision, Evaluation & Observability, LLM Frameworks | Evaluation & Observability, Inference & Serving, LLM Frameworks, Model Training | ## Trust and health _Sourced signals - not a safety guarantee. No winner column._ | | [uqlm](/tools/cvs-health-uqlm.md) | [FastChat](/tools/lm-sys-fastchat.md) | | --- | --- | --- | | Maintenance | Very active (96%) | Steady (60%) | | Days since push | 1d | 71d | | Open issues (now) | 23 | 1.0k | | Full report | [trust report](/tools/cvs-health-uqlm/trust.md) | [trust report](/tools/lm-sys-fastchat/trust.md) | ## Shared compatibility - **Python**: [uqlm](/tools/cvs-health-uqlm.md) - Python runtime; [FastChat](/tools/lm-sys-fastchat.md) - Python runtime ## Decision facts: FastChat - **Adopt for:** FastChat is a comprehensive open platform for managing large language models (LLMs) that includes capabilities for training, serving, evaluating, and comparing chatbot models via web UIs and RESTful APIs. It powers ChatB ## Choose when ### Choose uqlm if… - Tags unique to uqlm: ai evaluation, ai-safety, confidence-estimation, confidence-score. - Also covers Computer Vision. - More recently updated (last pushed Jul 9, 2026). ### Choose FastChat if… - Tags unique to FastChat: chatbots, distributed serving, evaluation system, large-language-models. - Also covers Inference & Serving, Model Training. - - You are looking to train and evaluate state-of-the-art models such as Vicuna or MT-Bench. ## When NOT to use uqlm - Evaluation & Observability: Defer heavyweight eval infra only until you have real traffic - never skip it once users depend on answers. - LLM Frameworks: Avoid a framework for a single prompt-and-retrieve call; the abstraction can cost more than it saves. ## When NOT to use FastChat - - You require a proprietary or closed-source framework; FastChat is open-source under Apache-2.0 license and its use might be unsuitable for environments requiring proprietary solutions. - - Your chatbot evaluation needs do not align with the types of data used in FastChat's datasets (e.g., human votes, MT-Bench evaluations). - - You prefer a more user-friendly setup without the need to clone a repository and manually install dependencies; FastChat requires installation from source with additional steps for Rust and CMake on - + Mac. ## Common questions ### What is the difference between uqlm and FastChat? uqlm: UQLM: Uncertainty Quantification for Language Models, is a Python package for UQ-based LLM hallucination detection. FastChat: An open platform for training, serving, and evaluating large language models. See the comparison table for live GitHub stats and shared categories. ### When should I choose uqlm over FastChat? Choose uqlm over FastChat when Tags unique to uqlm: ai evaluation, ai-safety, confidence-estimation, confidence-score; Also covers Computer Vision; More recently updated (last pushed Jul 9, 2026). ### When should I choose FastChat over uqlm? Choose FastChat over uqlm when Tags unique to FastChat: chatbots, distributed serving, evaluation system, large-language-models; Also covers Inference & Serving, Model Training; - You are looking to train and evaluate state-of-the-art models such as Vicuna or MT-Bench. ### When should I avoid uqlm? Evaluation & Observability: Defer heavyweight eval infra only until you have real traffic - never skip it once users depend on answers. LLM Frameworks: Avoid a framework for a single prompt-and-retrieve call; the abstraction can cost more than it saves. ### When should I avoid FastChat? - You require a proprietary or closed-source framework; FastChat is open-source under Apache-2.0 license and its use might be unsuitable for environments requiring proprietary solutions. - Your chatbot evaluation needs do not align with the types of data used in FastChat's datasets (e.g., human votes, MT-Bench evaluations). - You prefer a more user-friendly setup without the need to clone a repository and manually install dependencies; FastChat requires installation from source with additional steps for Rust and CMake on + Mac. ### Is uqlm or FastChat more popular on GitHub? FastChat has more GitHub stars (39,490 vs 1,183). Stars measure visibility, not whether either tool fits your constraints. ### Are uqlm and FastChat open source? Yes - both are open-source projects on GitHub (uqlm: Apache-2.0, FastChat: Apache-2.0). ### Where can I find alternatives to uqlm or FastChat? GraphCanon lists graph-backed alternatives at [uqlm alternatives](/tools/cvs-health-uqlm/alternatives) and [FastChat alternatives](/tools/lm-sys-fastchat/alternatives) ([uqlm markdown twin](/tools/cvs-health-uqlm/alternatives.md), [FastChat markdown twin](/tools/lm-sys-fastchat/alternatives.md)), ranked by typed relationship edges rather than popularity votes. ### Is there a machine-readable version of this comparison? Yes. The markdown twin at [this comparison](/compare/cvs-health-uqlm-vs-lm-sys-fastchat.md) mirrors this page for agents and LLM crawlers, with the same stats table and FAQ answers. ### Which is better maintained, uqlm or FastChat? uqlm: Very active. FastChat: Steady. Compare maintenance labels, days since push, and release cadence in the trust section below - stars alone do not measure maintenance. ### Where are the full trust reports for uqlm and FastChat? GraphCanon publishes per-repo trust reports with dated maintenance, provenance, and scan summaries: [uqlm trust report](/tools/cvs-health-uqlm/trust); [FastChat trust report](/tools/lm-sys-fastchat/trust). --- **Machine-readable endpoints** - JSON: [`/api/graphcanon/graph?tool=cvs-health-uqlm`](/api/graphcanon/graph?tool=cvs-health-uqlm) - LLM index: [/llms.txt](/llms.txt) - Full corpus: [/llms-full.txt](/llms-full.txt) _GraphCanon - The knowledge graph for AI development. https://www.graphcanon.com/_