WebDev Arena, an open-source project launched by lmarena_ai, allows users to compare the performance of various large language models (LLMs) in generating web applications. The platform features a comparison of web apps created by different LLMs, enabling users to vote for the best output. The project utilizes E2B sandboxes as a cloud runtime for executing the code generated by the LLMs. Users can test the models for free, with initial experiments indicating preferences among the LLMs. The launch has garnered support from developers and enthusiasts in the AI community.