Arena
Community-voting LLM leaderboard (formerly LMArena/Chatbot Arena) that now sells agent-evaluation analytics and a real-world alignment benchmark to AI labs.
Overview
Arena, the community platform formerly known as LMArena/Chatbot Arena (rebranded January 28, 2026), pairs free community model rankings with a paid analytics product, AI Evaluations, for AI labs and enterprises. On October 8, 2026 it announced a $200 million Series B at a $3.1 billion valuation co-led by Lightspeed Venture Partners and Khosla Ventures, alongside the Arena Alignment Index, a benchmark built from more than 90,000 real-world agent sessions across 27 models that scores agent behavioral reliability rather than raw capability.
This is a sourced directory entry. Features and capabilities are reported in the linked sources; this entry does not document independent Aymorphic testing.
Key features
- Free community leaderboard: users submit prompts/coding tasks and vote between model responses
- AI Evaluations: paid performance analytics for AI labs and enterprises based on community feedback
- Arena Alignment Index: scores three behavioral signals - Unauthorized Action, False Attribution, and Deceptive Completion - across 27 models and 90,000+ agent sessions
- Scoring methodology for the Alignment Index uses rubrics, an AI judge, and human review, but exact scoring weights are not publicly disclosed
Use cases
- Public, crowd-sourced comparison of LLM/chatbot quality
- Enterprise/lab procurement decisions using paid performance analytics
- Benchmarking agent behavioral reliability and compliance risk before production deployment
Pricing
Community leaderboard is free; AI Evaluations is a paid product for labs/enterprises (pricing not publicly disclosed). Company has exceeded $100M in annualized revenue.
Pricing reflects the source record and may change. Confirm current terms with the provider.
Dates and sources
- Released
- 8 Oct 2026
- Record updated
- 13 Oct 2026
- Record last checked
- 13 Oct 2026