Sider AI is a multi-model AI assistant that lives in a sidebar on top of any webpage, document, or video, giving instant access to leading models without switching tabs or apps. Trusted by more than 10 million users, it lets you chat with GPT-5.1, Claude Sonnet, Gemini, DeepSeek, and 20+ other models from one interface, and even compare their answers side by side in a Group AI Chat. Beyond conversation, Sider bundles a Deep Research Agent that scans 100+ web sources and produces structured, cited reports; one-click summarization for pages, PDFs, and YouTube videos; translation across 50+ languages; and content tools including an AI Writer, slide generation, and a Web Creator. Its image suite covers AI image generation, photo editing, and upscaling, while real-time web access keeps answers current. Sider works as a Chrome, Edge, and Safari extension and ships dedicated apps for macOS, Windows, iOS, and Android, making it a single hub for browsing, research, writing, and creative work. It is designed for students, researchers, marketers, and knowledge workers who want one assistant that follows them across every site and device.