Code Arena expands to fullstack AI evaluation, ranking 104 models as the AI coding wars heat up

The race to build the best AI coding assistant just got a proper scoreboard. Arena.ai, the platform formerly known as LMArena, has expanded its Code Arena from a frontend-only prototyping tool into a fullstack development evaluation platform, ranking AI models on their ability to build real, deployable web applications. As of July 27, 2026, the WebDev AI Leaderboard has accumulated 489,150 votes across 104 AI models. From prototypes to production-ready apps Code Arena originally launched in 2025 with a narrower focus: evaluating how well AI models could handle frontend code. Think UI components, layout generation, basic interactive elements. The fullstack upgrade, which went live on July 2, 2026, is a fundamentally different beast. The platform now supports PostgreSQL databases with authentication and Row Level Security, third-party API integrations, persistent sandboxes with hot reloading, and direct deployments to Vercel. The evaluation methodology relies on community-driven assessment. Users build real-time web apps using competing AI models, then vote on which model performed better. Who’s winning, and why it matters Anthropic’s claude-opus-5-max currently sits atop the leaderb...