AutoArena is an automated generative AI assessment platform focused on evaluating large language models (LLMs), retrieval-augmented generation (RAG) systems, and generative AI applications. It provides reliable assessments through automated head-to-head evaluations, helping users quickly, accurately, and economically find the best version of their systems. The platform supports evaluating models from various vendors such as OpenAI and Anthropic, as well as locally run open-source weight models. AutoArena also provides Elo scoring and confidence interval calculations to help users translate multiple head-to-head votes into leaderboard rankings. Additionally, AutoArena supports fine-tuning of custom evaluation models for more accurate, domain-specific assessments and can be integrated into continuous integration (CI) processes to automate the evaluation of generative AI systems.