The Best Open Source Grammarly AlternativesTop Grammar Checkers & AI Writing Tools like Grammarly

The best open source alternative to Grammarly is LanguageTool. If that doesn't suit you, our users have ranked more than 100 alternatives to Grammarly and 19 is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Grammarly are Grammalecte, Harper, Kerlig and Vale.

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Grammarly alternatives are mainly Grammar Checkers, but if you're looking for AI Writing Tools or AI Chatbots you can filter on that. Other popular filters include Open Source, Windows, iPhone, Linux, iPad, Apache OpenOffice and Mac. You can also filter by region, for example EU-based alternatives if you prefer software developed in the European Union. These are just examples - use the filter bar below to find more specific alternatives to Grammarly.
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Alternatives list

  1. LanguageTool icon

    LanguageTool

     186 likes
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    Proofreading software compatible with LibreOffice, Word, Firefox, and Chrome. Supports 20+ languages, offering two tiers: free and premium, with features like customizable checks, Microsoft add-on, and error detection in gender, ISBN, and IBAN. Offers open-source web and desktop versions.

    92 LanguageTool alternatives

    Cost / License

    • Freemium (Subscription)
    • Open Source

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • iPhone
    • iPad
    • Microsoft Edge
    • ONLYOFFICE
    • Google Chrome
    • Microsoft Outlook
    • Safari
    • Visual Studio Code
    • Microsoft Word
    • Eclipse
    • TinyMCE
    • Google Docs
    • Thunderbird
    • Vim
    • Sublime Text
    • GNU Emacs
    • Opera
    • Gmail
    • LibreOffice
    • Apache OpenOffice
    • Mozilla Firefox
    • LibreOffice - Writer
    • Cloudron
    LanguageTool screenshot 1
     
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    11
    133
    Comments about LanguageTool as an Alternative to Grammarly
    Comment summary: LanguageTool is praised for its multilingual support, affordability, open-source nature, and effective performance compared to Grammarly. Many users highlight its ability to function as well or better than Grammarly, mentioning its browser extension and privacy features. However, some comments criticize its ability to correct writing style beyond grammar and spelling, reporting issues with false negatives and punctuation assistance.
    Top Positive Comment
    RemovedUser
    6

    Open source, cheaper, works in more languages.

    Review by a new / low-activity user.
    Top Negative Comment
    Guest
    14

    It doesn't work very well. For example, it shows all is good if I type in the following: "Can you do plan by yourself? Yoda I speak like and check grammar I do. "

    Review by a new / low-activity user.
    Jan Klass
    1

    Note: Despite being listed here as "Country of Origin: DE, EU", while the website imprint does list a GmbH (German business), the privacy policy does not mention it; it mentions only the parent org Learneo and it includes data transfer to outside the EEA and into the US.

    Show more comments
    3 of 11 comments
    Grammarly Icon
    LanguageTool icon

    • Most users think LanguageTool is a great Grammarly alternative.

    • LanguageTool is the most popular Web-based, Windows, Mac & iPhone alternative to Grammarly.

    • LanguageTool is the most popular Open Source & free alternative to Grammarly.

    • LanguageTool is Freemium and Open SourceGrammarly is Freemium and Proprietary
    • LanguageTool is Privacy focusedGrammarly is not according to our users
  2. Grammalecte icon

    Grammalecte

     34 likes
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    Grammalecte is a French grammar checker.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Mac
    • Windows
    • Linux
    • Chrome OS
    • Google Chrome
    • Python
    • Thunderbird
    • Vim
    • Sublime Text
    • GNU Emacs
    • Pluma
    • LibreOffice
    • Mozilla Firefox
    • LibreOffice - Writer
    • ONLYOFFICE
    Grammalecte screenshot 1
     
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    11
  4. Harper icon

    Harper

     7 likes
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    Harper is an English grammar checker designed to be just right. I created it after years of dealing with the shortcomings of the competition.

    59 Harper alternatives

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Self-Hosted
    • WebAssembly
    • Visual Studio Code
    • Mac
    • Linux
    • Windows
    • Homebrew
    • Neovim
    Harper screenshot 1
     

    • Harper is the most popular Self-Hosted alternative to Grammarly.

    • Harper is Free and Open SourceGrammarly is Freemium and Proprietary
    • Harper is Privacy focusedGrammarly is not according to our users
  5. Ad
    Screenshot
    LanguageTool icon
    LanguageTool

    Proofreading software compatible with LibreOffice, Word, Firefox, and Chrome. Supports 20+ languages, offering two tiers: free and premium, with features like customizable checks, Microsoft add-on, and error detection in gender, ...

    https://languagetool.org
    Learn More
  6. Kerlig icon

    Kerlig

     8 likes
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    Kerlig for macOS brings AI to any app. It's your in-context AI writing assistant. No subscriptions. Works with OpenAI, Claude, Gemini, Groq.

    47 Kerlig alternatives

    Cost / License

    • Pay once
    • Open Source

    Application types

    Platforms

    • Mac
    Kerlig screenshot 1
     
  7. Vale icon

    Vale

     Like
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    Vale is an open-source, command-line tool that brings your editorial style guide to life.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Windows
    • Mac
    • Linux
    Vale screenshot 1
     
  8. Typopo icon

    Typopo

     2 likes
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    Typopo fixes microtypography errors that often require attentive eye and knowledge of local typography rules. It works for English, German, Slovak, Czech and Rusyn texts.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Online
    • Software as a Service (SaaS)
    Typopo–online app
     
  10. Eloquent Proofreading Assistant icon

    Eloquent Proofreading Assistant

     2 likes
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    Eloquent is a proofreading software for English, Spanish, French, German, Portuguese, Polish, Dutch, and more than 20 other languages. It finds many errors that a simple spell checker cannot detect.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Linux
    • Flathub
    • Flatpak
    Eloquent Proofreading Assistant screenshot 1
     
  11. RewritePal icon

    RewritePal

     5 likes
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    RewritePal is a free, AI-powered tool designed to make your writing clear, compelling, and tailored to any audience. Whether you're a student, professional, or content creator, RewritePal helps you transform paragraphs into polished, reader-friendly text in seconds.

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Online
    RewritePal screenshot 1
     
  12. Editsaurus icon

    Editsaurus

     14 likes
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    Highlights potential pitfalls in your writing to encourage good habits.

    61 Editsaurus alternatives

    Cost / License

    • Free
    • Open Source

    Application type

    Alerts

    • Discontinued

    Platforms

    • Online
    • Self-Hosted
    Editsaurus screenshot 1
     
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    6
  13. proselint icon

    proselint

     2 likes
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    Writing is notoriously hard, even for the best writers, and it's not for lack of good advice — a tremendous amount of knowledge about the craft is strewn across usage guides, dictionaries, technical manuals, essays, pamphlets, websites, and the hearts and minds of great...

    Cost / License

    • Free
    • Open Source

    Platforms

    • Linux
    • Python
     
  14. Grammark icon

    Grammark

     2 likes
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    Grammark helps improve writing style & grammar and teaches students to self-edit. Basically, it finds things that grammarians consider bad, highlights them, and suggests improvements.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Online
    • Self-Hosted
     
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    2
    Comments about Grammark as an Alternative to Grammarly
    pmilsom
    Positive
    0

    Grammark is very proficient Authors protector. It has to be used as a service and can't be downloaded into Libre Office. But it does a wonderful job in the smaller offerings that can be managed through a service.

    Review by a new / low-activity user.
    Guest
    Positive
    0

    Grammark has a "lean in" style with active voice that I like. It's a nuance but important.

    Review by a new / low-activity user.
    Grammarly Icon
    Grammark icon
    • Grammark is Free and Open SourceGrammarly is Freemium and Proprietary
  15. Scramble icon

    Scramble

     Like
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    Scramble is an open-source Chrome extension that leverages AI to enhance your writing directly in your browser. It's designed to be a more customizable and privacy-respecting alternative to Grammarly.

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Google Chrome
    Scramble screenshot 1
     
12 of 19 Grammarly alternatives