Puter delivers a complete cloud operating system that runs entirely in the browser — turning any device with internet access into a full-featured personal computer with desktop environment, file management, application hosting, and developer platform. The familiar desktop interface presents windows, taskbar, right-click menus, drag-and-drop, and multi-window management indistinguishable from native operating systems. The hierarchical filesystem supports file creation, uploads, sharing, permissions, and trash recovery with storage backends ranging from local SQLite for self-hosting to S3 and DynamoDB for production scale. Built-in AI integration provides access to GPT-4, Claude, and other models directly from the desktop for text generation, code assistance, and image creation. The developer platform offers a JavaScript SDK, REST APIs, cloud storage, key-value database, and serverless workers for building and hosting web applications without managing infrastructure. Sandboxed applications run in iframes with IPC communication and permission-based access to filesystem, AI, and system services. The app store enables publishing, discovering, and monetizing applications built on the Puter platform. Website hosting publishes static sites with custom domains directly from the file manager. Multi-user support provides individual accounts with authentication, resource isolation, and sharing capabilities. Deploy via Docker with a single command, Docker Compose for production, or npm for development — the one-line install script handles everything automatically on Linux, macOS, and Windows. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.