Compare Merlin AI and GPT Reader: Which Extension is the Best?

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
Transform any text into natural-sounding speech with this free ChatGPT-powered text-to-speech tool. We've tested its capabilities on short articles and lengthy PDFs.
Key Features
  • 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.
  • Text-to-Speech Conversion: Natural-sounding AI voices powered by ChatGPT
  • Document Support: Handles PDFs, Google Docs, and web content
  • Audio Download: Option to save generated audio for offline listening
  • Playback Controls: Adjustable speed, pause, and rewind functionality
  • Multi-format Support: Works with pasted text, documents, and website content
Our Rating
8.4
9.0
Total users
1,000,000
8,354
Total ratings
8,796
70
Average rating
4.8 ⭐
4.5 ⭐
Entry Level PriceFreeFree
Chrome
Chrome Web Store logo
4.8
3.12
8.8K+ ratings
1.0M+Users
Chrome Web Store logo
4.8
4.64
55 ratings
7.0K+Users
Edge
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-
Firefox
-
Mozilla Firefox Add-ons Store logo
4.3
3.92
15 ratings
1.4K+Users
Safari
-
-
Features
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
9.2

The functional scope of GPT Reader is designed for a wide range of users and demonstrated many useful functions in the test. The voice quality is surprisingly good and offers a natural-sounding output. We particularly liked the comprehensive format support, which seamlessly processes everything from PDFs to web content. The control of the playback is also well implemented, making it easy to adjust the speed directly and individually. However, the function for downloading audio files stood out the most in the test. In theory, entire books can be converted and then downloaded as audio books. However, this was the only area where we had to make deductions, as the free ChatGPT version had limitations when processing longer texts or documents.
We tried to convert a 300-page PDF and were able to process 22% of it, which corresponded to around 2 hours of audio. After this 22%, the free quota of requests on ChatGPT was reached, and the request was canceled.

Performance
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.

8.3

The performance tests showed a mixed picture. For shorter texts and paragraphs, GPT Reader processes content quickly and delivers a smooth rendering. The application is fast and reliable for typical use cases such as articles or short documents. Here we tested self-written summaries for learning purposes. However, we encountered significant limitations with larger files, as it is not possible to complete processing due to the limited number of requests. The option of pausing and then resuming would help here. In addition, the process takes a very long time for larger files; the extension needed around 40 minutes for around 75 pages of a PDF. The limitations of the ChatGPT API particularly affect the processing of longer documents such as entire books. This is currently only possible with a premium version of ChatGPT.

Design
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
9.0

The design of GPT Reader is clean and professional, with an intuitive layout that makes navigation effortless. The fact that there is even a dark as well as a light mode shows that the different user preferences have been taken into account. The controls are logically arranged and easily accessible. Even though the extension is designed for functionality, the design is not forgotten.

Value for Money
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.

8.9

Currently, GPT Reader offers a very good price-performance ratio, as all functions are available completely free of charge. We found no hidden costs or unexpected limitations in the free version.
The features should be sufficient for most users; the only thing to note is the limited number of requests per hour that ChatGPT allows. If you need to convert entire books into one, you will need a premium version of ChatGPT.
It should also be mentioned that the extension already indicates that the download function may be offered in a paid version in the future, which could influence this rating in the future.

future premium function

At the moment, however, it is a very good offer in the text-to-speech sector.

Ease of 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.

8.7

In terms of user-friendliness, GPT Reader scores very well. Users of all technical levels should have little problem simply converting text to audio. The user interface is self-explanatory, and all functions are displayed immediately.
The only negative point is that a separate ChatGPT registration is still required, and an error message appears if the ChatGPT requests are exceeded, which can lead to confusion.

Security & Privacy
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.

9.7

In our security analysis, GPT Reader showed a strong commitment to protecting user privacy. The extension only collects data from user-reported bugs and feedback. We appreciated the transparent privacy policy, where the user can read specific points.

Conclusion

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.

GPT Reader is a promising text-to-speech extension based on ChatGPT voices. The easy-to-understand voices, combined with the fact that it is completely free, set it apart from conventional TTS tools.

The extension can process various document formats. Both PDFs and copied web articles can be converted, but it has its limitations with longer texts. For example, a 300-page PDF was only partially converted in the text due to ChatGPT's limitations, which still resulted in about 2 hours of audio.

The tool is very user-friendly and supports multiple languages. This extension is a must for anyone who wants to listen to texts.

Our Recommendation

In our comparison between Merlin AI and GPT Reader, GPT Reader came out on top, scoring 9.

Merlin AI is the most widely used, with over 1 million users and 9k+ reviews, but GPT Reader outperformed it in our review. User reviews for GPT Reader 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.

There are some noticeable differences between these extensions, so it's worth considering your priorities and the details below.


  • Looking for the richest feature set? GPT Reader stands out with a rating of 9.2. On the other hand, Merlin AI lags behind in this area with a rating of 8.
  • Need top performance? GPT Reader stands out with a rating of 8.3. 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, GPT Reader lags behind in this area with a rating of 9.
  • Want to get the most for your money? GPT Reader stands out with a rating of 8.9. On the other hand, Merlin AI lags behind in this area with a rating of 8.2.
  • If you hate complicated tools, GPT Reader stands out with a rating of 8.7. On the other hand, Merlin AI lags behind in this area with a rating of 8.5.
  • With privacy and security becoming ever more important, GPT Reader stands out with a rating of 9.7. On the other hand, Merlin AI lags behind in this area with a rating of 9.3.

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