Merlin vs Monica
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
AI tool · Freemium
A browser extension giving access to several AI models on any page, for summarising, writing and chat.
AI tool · Freemium
An AI assistant extension for chat, reading, writing and translation on any website.
The short answer
Choose Merlin if you need…
- Summarising pages and YouTube videos
- Multi-model chat in the browser
Choose Monica if you need…
- Translating and summarising web content
- Quick writing help
Side-by-side
| Merlin | Monica | |
|---|---|---|
| Type | Plugins & extensions · AI browser extensions | Plugins & extensions · AI browser extensions |
| Price | Freemium | Freemium |
| Platforms | Chrome, Web, iOS, Android | Chrome, Web, iOS, Android, macOS, Windows |
| Works with | Chrome, Gmail | Chrome |
| Hands-on tested by us | Not yet | Not yet |
| Last checked | 2026-10-29 | 2026-10-29 |
What each one is
Merlin
A browser extension giving access to several AI models on any page, for summarising, writing and chat. Handy all-in-one sidebar. It can read the pages you visit, so review its permissions.
Monica
An AI assistant extension for chat, reading, writing and translation on any website. Broad feature set. Usage limits on top models are tight on cheaper plans.
Best for
Merlin
- Summarising pages and YouTube videos
- Multi-model chat in the browser
Monica
- Translating and summarising web content
- Quick writing help
Strengths
Merlin
- Sidebar chat with multiple models
- Page and video summaries
- Writing help in text fields
Monica
- Multi-model chat
- Bilingual page translation
- PDF and video summaries
- Writing tools
Frequently asked questions
What is the difference between Merlin and Monica?
Merlin: A browser extension giving access to several AI models on any page, for summarising, writing and chat. Monica: An AI assistant extension for chat, reading, writing and translation on any website. Merlin suits summarising pages and youtube videos, while Monica suits translating and summarising web content.
Are Merlin and Monica free?
Merlin: Freemium. Monica: Freemium.
What are other alternatives to Merlin and Monica?
Other options people compare them with include MaxAI, HARPA AI, Sider.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.