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Side Space vs Sider

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. Side Space starts at $2.90, Sider at $10. Both have a free tier.

Side SpaceBrowser sidebar that groups tabs into spaces and runs an agent over what you have open.SiderBrowser sidebar that puts GPT, Claude, Gemini, and other models next to any page you're reading.

Side by side

FactSide SpaceSider
CategoryBrowser Extensions & CopilotsBrowser Extensions & Copilots
Pricing modelFreemiumFreemium
Starts at$2.90 month$10 month
Public APINoNo
PlatformsChrome ExtWeb, Chrome Ext, Windows, macOS, iOS, Android
CompanyCursorDance, LLCSider
Last verifiedSep 6, 2026Sep 1, 2026

What our research says

Side Space

Tab management plus a chat that can actually see the tabs is a better combination than either half alone, and at $2.90 a month it is one of the cheapest paid extensions in this category. Note the rename: the product you find as Side Space is now Side Copilot, which matters when you search for support or reviews. Agent mode driving your live browser is the part to think about before installing.

Pros

  • Vertical tab sidebar with named spaces, free up to five
  • Chat mode answers across the tabs currently open
  • Agent mode automates grouping, history search and workspace rearrangement
  • Installs on Chrome, Edge, Brave, Vivaldi, Comet, Dia, Sigma, Firefox and Zen
  • $2.90/month is low for the category, with a 7-day refund window

Cons

  • Rebranded from Side Space, so older reviews and links point at a dead name
  • Agent mode needs broad permissions over your browsing
  • No Safari support
  • CursorDance, LLC publishes no address or team page

Sider

Sider puts a chat panel on top of whatever page you're on, so you can ask about an article or PDF without copying it into a separate tab. The catch is that heavier use beyond the free daily cap needs a paid tier, and pricing quoted across review sites is inconsistent, so the entry price is worth confirming before committing.

Pros

  • Works as a sidebar on any web page rather than a separate chat tab
  • Routes one prompt to several models (GPT, Claude, Gemini, DeepSeek, Grok)
  • Ships native apps for iOS, Android, Windows, and Mac plus browser extensions
  • Can chat with PDFs and YouTube videos, not just plain text

Cons

  • Free tier is capped at a small number of daily uses
  • Independent pricing write-ups disagree on exact plan costs depending on where you check
  • No public API for developers

Which one fits

Choose Side Space if you need

  • people who keep dozens of tabs open across projects
  • researchers who want to query several open pages at once
  • anyone on a Chromium browser other than Chrome

Choose Sider if you need

  • Reading and summarizing long articles or PDFs without leaving the page
  • Comparing answers from several models in one panel
  • People who want one subscription instead of several separate chatbot logins

More comparisons

All Side Space alternatives →Browse all Browser Extensions & Copilots →