--- title: "CommonGen-Eval vs FastChat" type: "comparison" canonical_url: "https://www.graphcanon.com/compare/allenai-commongen-eval-vs-lm-sys-fastchat" tools: ["allenai-commongen-eval", "lm-sys-fastchat"] --- # CommonGen-Eval vs FastChat *GraphCanon updated Jul 15, 2026* ## Verdict Pick CommonGen-Eval when tags unique to CommonGen-Eval: chatgpt, evaluation, gpt-evaluation, llama2; pick FastChat when tags unique to FastChat: chatbots, distributed-serving, evaluation system, large-language-models. [CommonGen-Eval](https://inklab.usc.edu/CommonGen/) reports 95 GitHub stars, 3 forks, and 1 open issues, last pushed Mar 21, 2024. [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 [CommonGen-Eval's repository](https://github.com/allenai/CommonGen-Eval) and [FastChat's repository](https://github.com/lm-sys/FastChat). | | [CommonGen-Eval](/tools/allenai-commongen-eval.md) | [FastChat](/tools/lm-sys-fastchat.md) | | --- | --- | --- | | Tagline | Evaluating LLMs with CommonGen-Lite | An open platform for training, serving, and evaluating large language models | | Stars | 95 | 39,494 | | Forks | 3 | 4,786 | | Open issues | 1 | 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 | Evaluation & Observability, LLM Frameworks | Evaluation & Observability, Inference & Serving, LLM Frameworks, Model Training | ## Trust and health _Sourced signals - not a safety guarantee. No winner column._ | | [CommonGen-Eval](/tools/allenai-commongen-eval.md) | [FastChat](/tools/lm-sys-fastchat.md) | | --- | --- | --- | | Maintenance | Dormant (18%) | Steady (60%) | | Days since push | 846d | 74d | | Open issues (now) | 1 | 1.0k | | Full report | [trust report](/tools/allenai-commongen-eval/trust.md) | [trust report](/tools/lm-sys-fastchat/trust.md) | ## Shared compatibility - **Python**: [CommonGen-Eval](/tools/allenai-commongen-eval.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 CommonGen-Eval if… - Tags unique to CommonGen-Eval: chatgpt, evaluation, gpt-evaluation, llama2. - Leaner open-issue backlog (1). ### 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 CommonGen-Eval - Last GitHub push was 846 days ago (dormant maintenance, Mar 21, 2024). Validate activity before betting a new project on CommonGen-Eval. - 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 CommonGen-Eval and FastChat? CommonGen-Eval: Evaluating LLMs with CommonGen-Lite. 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 CommonGen-Eval over FastChat? Choose CommonGen-Eval over FastChat when Tags unique to CommonGen-Eval: chatgpt, evaluation, gpt-evaluation, llama2; Leaner open-issue backlog (1). ### When should I choose FastChat over CommonGen-Eval? Choose FastChat over CommonGen-Eval 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 CommonGen-Eval? Last GitHub push was 846 days ago (dormant maintenance, Mar 21, 2024). Validate activity before betting a new project on CommonGen-Eval. 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 CommonGen-Eval or FastChat more popular on GitHub? FastChat has more GitHub stars (39,494 vs 95). Stars measure visibility, not whether either tool fits your constraints. ### Are CommonGen-Eval and FastChat open source? Yes - both are open-source projects on GitHub (CommonGen-Eval: Apache-2.0, FastChat: Apache-2.0). ### Where can I find alternatives to CommonGen-Eval or FastChat? GraphCanon lists graph-backed alternatives at [CommonGen-Eval alternatives](/tools/allenai-commongen-eval/alternatives) and [FastChat alternatives](/tools/lm-sys-fastchat/alternatives) ([CommonGen-Eval markdown twin](/tools/allenai-commongen-eval/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/allenai-commongen-eval-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, CommonGen-Eval or FastChat? CommonGen-Eval: Dormant. 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 CommonGen-Eval and FastChat? GraphCanon publishes per-repo trust reports with dated maintenance, provenance, and scan summaries: [CommonGen-Eval trust report](/tools/allenai-commongen-eval/trust); [FastChat trust report](/tools/lm-sys-fastchat/trust). --- **Machine-readable endpoints** - JSON: [`/api/graphcanon/graph?tool=allenai-commongen-eval`](/api/graphcanon/graph?tool=allenai-commongen-eval) - 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/_