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Monica vs Side Space

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 publishes a starting price ($2.90); Monica does not. Both have a free tier. Only Monica ships a public API.

MonicaMulti-model AI assistant living in a browser sidebarSide SpaceBrowser sidebar that groups tabs into spaces and runs an agent over what you have open.

Side by side

FactMonicaSide Space
CategoryBrowser Extensions & CopilotsBrowser Extensions & Copilots
Pricing modelFreemiumFreemium
Starts at—$2.90 month
Public APIYesNo
PlatformsWeb, macOS, Windows, iOS, Android, API, Chrome ExtChrome Ext
CompanyButterfly Effect Pte. Ltd.CursorDance, LLC
Launched2023—
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

Monica

Worth it if you want one subscription that reaches GPT, Claude and Gemini from wherever you already are; pointless if you live inside a single vendor's app and are happy there. The value is the sidebar and the model switching, not the intelligence, which is all rented.

Pros

  • Genuinely wide model roster, including image and video models, under one credit pool
  • Extension plus desktop plus iOS/Android means the same history follows you across devices
  • Separate prepaid developer API at platform.monica.im if you want the same aggregation in code

Cons

  • Prices are only visible after loading the pricing app, and the tier names have already shifted once (Unlimited became Max)
  • Advanced credits reset monthly, so heavy image or video use burns a Pro plan fast
  • You are a reseller's customer — outages, rate limits and model deprecations arrive second-hand
  • monica.cn is a separate China-market build run by a different legal entity, which confuses support and privacy expectations

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

Which one fits

Choose Monica if you need

  • People who compare answers across GPT, Claude and Gemini without paying three subscriptions
  • Reading and summarising foreign-language pages and PDFs in-place while browsing
  • Light users who want AI attached to the browser rather than in another tab

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

More comparisons

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