Compare Quillbot and Merlin AI: Which Extension is the Best?

Quillbot is an AI-powered writing assistant designed to enhance your writing with features like paraphrasing, grammar checking, and summarizing. Ideal for productivity and improving writing quality.
Merlin AI is a browser extension and web app that unifies top AI models (ChatGPT, Claude, Gemini, Mistral) for research, summarizing, writing, coding, diagramming, translation, and more—directly in yo
Key Features
  • Paraphrasing Tool: Rewrites your sentences to improve clarity and style.
  • Grammar Checker: Identifies and corrects grammatical errors.
  • Summarizer: Condenses long texts into shorter summaries.
  • Citation Generator: Helps you create citations in various formats.
  • Plagiarism Checker: Ensures your content is original.
  • Unified AI Models: Access ChatGPT, Claude, Gemini, Mistral, and more from one account—no need for separate logins.
  • Research & Summarize: Summarize web pages, YouTube videos, PDFs, and documents instantly.
  • Content Creation: Write emails, social media posts, blogs, and outreach messages with AI assistance.
  • Projects: Build custom AI chatbots using your own files, links, or knowledge ba
  • Crafts: Instantly generate code snippets, diagrams, and mindmaps
  • Live Search: Get up-to-date answers by searching the web in real time.
  • Multi-language Support: Translate content into 25+ languages.
  • Keyboard Shortcuts: Quickly summon Merlin with Ctrl/Cmd+M anywhere in your browser.
Our Rating
8.7
8.4
Total users
4,485,643
1,000,000
Total ratings
3,036
8,802
Average rating
4.6 ⭐
4.8 ⭐
Entry Level PriceFreeFree
Chrome
Chrome Web Store logo
4.7
4.88
2.9K+ ratings
4.0M+Users
Chrome Web Store logo
4.8
3.24
8.8K+ ratings
1.0M+Users
Edge
Microsoft Edge Store logo
4.5
4.47
104 ratings
485.6K+Users
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Firefox
-
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Safari
-
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Features
9.0

Paraphrasing Tool:
Quillbot's paraphrasing tool is one of its standout features. It offers multiple modes like Standard, Fluency, and Creative, allowing users to choose the level of rewriting they need. We found it particularly useful for avoiding plagiarism and improving sentence structure.

Grammar Checker:
The grammar checker is robust, catching errors that many basic spell checkers miss. However, it sometimes flagged correct sentences as incorrect, which can be a bit annoying.

Summarizer:
Quillbot's summarizer is effective for condensing long articles or papers. It provides concise summaries that capture the main points, making it a valuable tool for students and professionals alike.

8.0

Merlin AI offers a variety of features including summarizing, writing, coding, diagramming and more. It supports multiple AI models such as GPT-4, Claude and Gemini and allows users to create custom AI chatbots and knowledge bases. The platform also integrates with the web and files in real time. However, some features, such as PDF summarization, are not as robust as those of specialized tools. It also lacks what we consider to be the important function of direct communication between AI and the current website. In addition, the function of direct communication between AI and the current website, which we consider important, is missing.

Missing Feature
Performance
8.8

Quillbot performs well with small to medium-sized texts, but it can slow down when processing larger documents.

7.5

Merlin is generally fast and responsive, but it can slow down browsers, especially on older hardware. There are occasional bugs and crashes, though the team releases frequent updates and improvements.

Design
9.0

User Interface:
Quillbot boasts a clean and intuitive interface. The layout is straightforward, making it easy for users to navigate through different features without any hassle.

Customization:
The tool offers various customization options, such as different paraphrasing modes and the ability to adjust the length of summaries. These features make it adaptable to different writing needs.

9.1

The design has a modern look and feel, with handy keyboard shortcuts and sidebar integration that make navigation easier. That said, the user interface can feel cluttered and overwhelming, especially for new users, and there are inconsistencies between the extension, web, and mobile versions.

Design
Value for Money
9.0

Free vs. Paid:
While the free version offers basic functionality, the premium plans unlock a wealth of features that significantly enhance the tool's utility.

Cost-Effectiveness:
Compared to its competitors, Quillbot is slightly cheaper than Grammarly but more expensive than LanguageTool. From our perspective, Quillbot doesn't offer more value than LanguageTool, so we believe it should be priced similarly. However, it currently offers significant discounts on their plans, which makes it a very good investment in your writing.

8.2

The free plan is generous for light users, offering a substantial daily quota and access to a wide range of basic features. The Pro plan is competitively priced, especially when compared to the cost of subscribing to multiple separate AI tools, and unlocks unlimited access to all models and advanced features. However, the absence of a free trial for premium features means users must commit before experiencing the full capabilities of Merlin AI. Additionally, some users report that the query system—where different models and features consume varying amounts of daily queries—can be confusing or feel restrictive, particularly for those trying to understand how far their usage will go on each plan.

Ease of Use
7.8

Quillbot's onboarding process is impressive, and the tool is easy to use right from the start. We quickly grasped most of its features. However, when compared to top competitors like Grammarly, it doesn't feel quite as natural or seamless to use.

8.5

Getting started with Merlin AI is straightforward—installation is quick, and the onboarding process is simple enough for most users to begin using core features right away. However, the platform’s extensive feature set can be overwhelming at first, leading to a noticeable learning curve as users explore everything it offers. Some users have expressed confusion about how the daily query limits work, how different models are selected or switched, and which features are available on each plan. Occasional bugs and log-in issues can also disrupt the workflow, requiring users to troubleshoot or reach out to support. Overall, while Merlin AI is accessible, mastering its full capabilities may take some time and patience, especially for those new to AI tools.

Security & Privacy
8.8

Data Handling:
Quillbot ensures that user data is encrypted and securely stored. However, like many AI tools, it does send data to its servers for processing, which may raise privacy concerns for some users.

Third-Party Services:
The tool uses third-party services for certain features, which could lead to data being processed outside of the EU. Users should be cautious when handling sensitive information.

9.3

Merlin does not sell user data to third parties and only uses data for core functionality. The privacy policy is transparent, but some users remain concerned about the amount of data collected and the permissions required.

Conclusion

Quillbot is a flexible AI writing tool that does a great job with paraphrasing and grammar checking.

While it has a few minor downsides, like occasional mistakes and some privacy concerns, its overall performance and affordability make it a solid choice. In the end, choosing the best writing tool is also a matter of personal opinion. If you want to improve your writing and boost productivity, Quillbot is definitely worth a look.

However, it still cannot compete with Grammarly as the best writing tool in this category. In our eyes, Grammarly is worth the more expensive price.

Merlin AI is a powerful and versatile tool that can really boost the productivity of a wide range of users. The integration of multiple AI models and functions into a single extension is ideal for this p

However, Merlin is not completely perfect. We encountered occasional bugs, inconsistencies in the user interface and some performance issues. Pricing can also be confusing, and some features are locked behind a paywall..

Overall, Merlin AI is a good choice for anyone looking for an all-in-one AI assistant for the browser - especially if you value having multiple AI models and tools in one place.

Our Recommendation

In our comparison between Quillbot and Merlin AI, Quillbot came out on top, scoring 8.7.

Quillbot is the most widely used, with over 4 million users and 3k+ reviews—and it also delivered the strongest performance in our tests. User reviews for Quillbot reflect our findings, while we rate Merlin AI lower than users do.

Notably, Merlin AI has the highest user rating in the Chrome Web Store at 4.80, which is even higher than our rating of 8.4.

In the end, the differences between these extensions are minimal, so your choice may come down to personal preference or specific features.


  • Looking for the richest feature set? Quillbot stands out with a rating of 9. On the other hand, Merlin AI lags behind in this area with a rating of 8.
  • Need top performance? Quillbot stands out with a rating of 8.8. On the other hand, Merlin AI lags behind in this area with a rating of 7.5.
  • Design lovers, take note: Merlin AI stands out with a rating of 9.1. On the other hand, Quillbot lags behind in this area with a rating of 9.
  • Want to get the most for your money? Quillbot stands out with a rating of 9. On the other hand, Merlin AI lags behind in this area with a rating of 8.2.
  • If you hate complicated tools, Merlin AI stands out with a rating of 8.5. On the other hand, Quillbot lags behind in this area with a rating of 7.8.
  • With privacy and security becoming ever more important, Merlin AI stands out with a rating of 9.3. On the other hand, Quillbot lags behind in this area with a rating of 8.8.

If you want a quick recommendation, Quillbot is our top pick. But as always, the best choice depends on what matters most to you.