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Merlin AI vs Monica

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. Both have a free tier. Only Monica ships a public API.

Merlin AIBrowser sidebar running many chat models on any pageMonicaMulti-model AI assistant living in a browser sidebar

Side by side

FactMerlin AIMonica
CategoryBrowser Extensions & CopilotsBrowser Extensions & Copilots
Pricing modelFreemiumFreemium
Public APINoYes
PlatformsWeb, Chrome Ext, iOS, AndroidWeb, macOS, Windows, iOS, Android, API, Chrome Ext
CompanyFoyer Tech Inc.Butterfly Effect Pte. Ltd.
Launched20222023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

Merlin AI

Buy it if you genuinely rotate between GPT, Claude and Gemini and resent paying three subscriptions — the aggregation is the whole value. If you live inside one model, its native app is faster, cheaper and gets features first.

Pros

  • One subscription reaches a dozen-plus frontier and open models
  • Extension surfaces the assistant directly on Gmail, YouTube, Google and LinkedIn
  • Mobile apps sync history, so the browser session continues off desktop
  • Real free tier for evaluating before paying

Cons

  • 'Unlimited' paid plans are governed by an opaque fair-use credit budget users hit without warning
  • Extension is desktop-Chromium only; mobile browsers get a reduced web app
  • Feature parity with each underlying model's own app is never complete
  • No developer API

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

Which one fits

Choose Merlin AI if you need

  • People who compare answers across frontier models before trusting one
  • Heavy in-browser workflows: summarising videos, articles and inbox threads in place
  • Users who want one bill instead of separate OpenAI, Anthropic and Google subscriptions

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

More comparisons

All Merlin AI alternatives →All Monica alternatives →Browse all Browser Extensions & Copilots →