Sider is listed under Browser Extensions & Copilots, in the AI Chat & Assistants category on Flocci AI Tools. ChatGPT/Claude/Gemini in a browser sidebar. It is freemium — a usable free tier with paid plans above it, and it lives at sider.ai.
Sider is freemium: there is a free tier you can work in and paid plans above it. It is one of 391 freemium tools in the catalog, all labelled the same way so you are never surprised by a paywall.
Sider does 4 things the catalog singles out: Chatgpt/claude/gemini in a browser sidebar; summarize any page, pdf or youtube video; translate, rewrite and explain selections; works across every website.
Opera Browser AI (Aria) is the closest free alternative: it sits in the same Browser Extensions & Copilots sub-category and is free. Brave Leo, Dia and Harpa AI also start free. The full list is on the alternatives page.
See the full list →