Sider

Sider is an AI sidebar and agent for the browser, built on the idea that AI help should sit next to the page you are already reading instead of in a separate tab. Its homepage sums the product up as one AI sidebar for everything you do in the browser, and the vendor reports more than 10 million active users and more than 100,000 five star ratings, along with Chrome Editors Picks recognition in 2026 and a Favorites of the Year pick in 2025. It works as a browser extension, so the assistant travels with you across sites. Sider organizes its work into three modes named Chat, Hand, and Code. Sider Chat is for understanding: ask about any page using models the homepage names as GPT, Claude, or Gemini, and it can summarize, explain, translate, and explore content across web pages, PDFs, and YouTube videos, then answer follow ups in context. Sider Hand is for automation: give it a task and it works across real websites, using your logged in sessions, to research, compare, extract, and organize information, turning multi step work into usable results hands free. Sider Code is for customization: tell it in plain words what to change on a website, and it edits, restyles, or simplifies the page in real time and remembers your changes for future visits. The research side runs deeper than a quick summary. Its product description highlights deep, human like research completed within minutes, smart highlights, automatic note taking, visualized and interactive research reports, and a Wisebase for organizing knowledge, plus instant translation across more than 50 languages and summaries of pages and YouTube videos. That makes Sider as much a reading and research companion as a chatbot, aimed at people whose workday is spent in the browser. Sider suits students, researchers, analysts, and knowledge workers who read, watch, and compare sources online all day and want summaries, explanations, translations, and extracted notes without copying text into a separate AI tool. If you mainly want a standalone chat window, the other assistants in this category fit better. If your bottleneck is understanding what is already open in your browser, and occasionally handing a multi step web task to an agent, Sider is the specialist worth testing first.