Sider

Sider is one of the most-installed AI browser extensions on Chrome, Edge, Safari, and Firefox, with millions of users worldwide. The product layers a context-aware chat sidebar over any tab so users can summarize an article, translate a page, get explanations of complex text, fact-check claims, or have a freeform conversation grounded in what is on screen. The sidebar can be hidden, reshaped, and pinned to specific sites, making it unobtrusive when not needed.

The model layer is multi-provider: Sider routes between GPT-4-class models, Claude, Gemini, and others, with users on paid plans choosing their preferred model per conversation. The product also bundles its own fine-tuned models tuned for tasks like translation, grammar improvement, and summarization, which keep cost low for high-volume features. A 'group chat' mode lets multiple models answer the same question for comparison.

Beyond chat, Sider includes built-in tools that have become some of its most-used features: a writing assistant that polishes prose and adjusts tone, a translator that handles 50+ languages with context-aware quality, an image-generation surface tied to popular diffusion models, a PDF chat that handles long documents, and a YouTube summarizer that turns a video into a chaptered outline with timestamped highlights.

Sider runs as a free tier with daily limits and Pro / Advanced paid tiers for higher usage and premium model access. Enterprise plans add SSO and admin controls for company-wide deployments. The product is best suited for knowledge workers, researchers, students, and casual users who want broad-purpose AI assistance across the entire browsing experience rather than a single-app tool. Sider has been operating since the early days of GPT-3.5 integration and is one of the more polished, performant offerings in the all-in-one browser-AI category.