Compare LanguageTool and Merlin AI: Which Extension is the Best?
| Key Features A summary of the most important features offered by each extension. |
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| Our Rating Tooltivity's expert review score for each extension, based on hands-on testing and research. | 8.8 Winner in this category | 8.4 |
| Total users Total active users across all major browsers: Chrome, Edge, Firefox, and Safari. | 3,173,195 Winner in this category | 1,000,000 |
| Total ratings Total number of user ratings received across all supported browsers. | 16,550 Winner in this category | 8,802 |
| Average rating Average user rating across all browsers, calculated from available store ratings. | 4.8 ⭐ | 4.8 ⭐ Winner in this category |
| Entry Level Price The minimum price required to start using the extension. "Free" means a free tier is available. | Free | Free |
| Chrome User rating and stats for the extension on Chrome browser. |  4.8 4.75 Average Chrome Web Store rating from the last 100 reviews 2.0M+Users Winner in this category | 4.8 3.24 Average Chrome Web Store rating from the last 100 reviews 1.0M+Users |
| Edge User rating and stats for the extension on Edge browser. |  4.8 4.62 Average Microsoft Edge Store rating from the last 100 reviews 801.3K+Users Winner in this category | - |
| Firefox User rating and stats for the extension on Firefox browser. |  4.7 4.58 Average Mozilla Firefox Add-ons Store rating from the last 100 reviews 371.9K+Users Winner in this category | - |
| Safari User rating and stats for the extension on Safari browser. | - | - |
| Features Tooltivity's expert score for the 'Features' aspect of each extension. | 9.0 LanguageTool offers a comprehensive set of features that go beyond basic grammar and spelling checks. It supports over 20 languages, making it a versatile tool for multilingual users. The advanced grammar checks are particularly impressive, catching complex issues that many other tools miss. Compared to competitors like Grammarly, LanguageTool holds its own with unique features like custom dictionaries and plagiarism detection. Winner in this category | 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.  |
| Performance Tooltivity's expert score for the 'Performance' aspect of each extension. | 8.0 LanguageTool does a good job of spotting grammar and style issues. However, it can take a while to process longer texts, and sometimes, clicking on suggestions causes the page to jump to the top, which can be a bit frustrating. Winner in this category | 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 Tooltivity's expert score for the 'Design' aspect of each extension. | 8.0 The design is clean and intuitive, making it easy for users to navigate and utilize the tool effectively. The browser integration is seamless, and the user interface is straightforward. | 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.  Winner in this category |
| Value for Money Tooltivity's expert score for the 'Value for Money' aspect of each extension. | 9.5 The free version gives you the basics, but the premium version really shines with its advanced features. While Grammarly can be expensive, LanguageTool offers great value at a more affordable price. So, if you’re seeking a budget-friendly alternative to Grammarly, LanguageTool is a solid choice. Winner in this category | 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 Tooltivity's expert score for the 'Ease of Use' aspect of each extension. | 9.0 LanguageTool is very user-friendly, with a minimal learning curve. Most users will find it easy to get started and make the most of its features right out of the box. Winner in this category | 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 Tooltivity's expert score for the 'Security & Privacy' aspect of each extension. | 9.5 LanguageTool takes privacy seriously. No account is required for basic features, and the tool ensures that user data is not sold or made public. This focus on privacy is a significant plus. LanguageTool states that it is GDPR compliant which makes it especially interesting for users in Europe. Winner in this category | 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 A summary of our findings and final thoughts for each extension. | LanguageTool is a reliable and efficient writing assistant that supports multiple languages. Its advanced grammar and style checks make it a valuable tool for writers and professionals. While the premium version offers excellent features, the free version is somewhat limited. Overall, LanguageTool is a solid choice for anyone looking to improve their writing. Compared to Grammarly, LanguageTool holds its own, especially if you need to write in multiple languages. When it comes to writing in different languages, LanguageTool is the way to go. But if you’re only writing in English, Grammarly still delivers better results. | 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 LanguageTool and Merlin AI, LanguageTool came out on top, scoring 8.8. LanguageTool is the most widely used, with over 3 million users and 17k+ reviews—and it also delivered the strongest performance in our tests. User reviews for LanguageTool 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.
If you want a quick recommendation, LanguageTool is our top pick. But as always, the best choice depends on what matters most to you. | |
