Codeium is a free AI code completion and chat service that enables developers to rapidly generate code with accuracy and speed. Its key features include AI Autocomplete, Intelligent Search, AI-Powered Chat, Generative Models, and End-to-End Data Encryption. The key use cases include increasing productivity through code completion, engaging with the community through chat, deploying enterprise-level usage statistics, providing priority support, and offering end-to-end data encryption for security.