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 many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Grammarly are Harper, Onit AI, Grammalecte and Vale.

filter to find the best alternatives

Grammarly alternatives are mainly Grammar Checkers, but if you're looking for AI Writing Tools or Text to Speech Services you can filter on that. Other popular filters include Open Source, Windows, iPhone, Linux, iPad, Apache OpenOffice and Android. 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

     189 likes

    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.

    118 LanguageTool alternatives

    Cost / License

    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
    • Cloudron
    • Sublime Text
    • GNU Emacs
    • Opera
    • Gmail
    • LibreOffice
    • Apache OpenOffice
    • Mozilla Firefox
    • LibreOffice - Writer
    LanguageTool screenshot 1
     
    |
    11
    LanguageTool vs Grammarly Comments
    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.

    3 of 11 comments
    • LanguageTool is Freemium and Open SourceGrammarly is Freemium and Proprietary
    • LanguageTool is Privacy focusedGrammarly is not according to our users
  2. Harper icon

    Harper

     14 likes

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

    71 Harper alternatives

    Cost / License

    Application type

    Platforms

    • Self-Hosted
    • WebAssembly
    • Visual Studio Code
    • Mac
    • Linux
    • Windows
    • Homebrew
    • Neovim
    Harper screenshot 1
     
    |
    1
    Harper vs Grammarly Comments
    Guest
    Positive
    0

    Great open source product

    Review by a new / low-activity user.
    • Harper is Free and Open SourceGrammarly is Freemium and Proprietary
    • Harper is Privacy focusedGrammarly is not according to our users
  4. Onit AI icon

    Onit AI

     10 likes

    Onit AI Copilot offers a comprehensive desktop AI chat assistant with local processing and multi-provider support. It prioritizes customization, extensibility, and user privacy by operating entirely on-device without needing an internet connection, ensuring data security.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Mac
    Onit AI screenshot 1
     
  5. Grammalecte icon

    Grammalecte

     33 likes

    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
     
  7. Vale icon

    Vale

     2 likes

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

    Cost / License

    • Free
    • Open Source (MIT)

    Platforms

    • Windows
    • Mac
    • Linux
    Vale screenshot 1
     
  8. Eloquent Proofreading Assistant icon

    Eloquent Proofreading Assistant

     4 likes

    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

    Application type

    Platforms

    • Linux
    • Flathub
    • Flatpak
    Eloquent Proofreading Assistant screenshot 1
     
  9. Typopo icon

    Typopo

     2 likes

    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 (MIT)

    Platforms

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

    AssisT

     1 like

    AssisT is a free, open-source Chrome extension that adds text-to-speech with word-by-word highlighting, speech-to-text, AI writing assistance, and 35+ accessibility features to Canvas LMS, Moodle, Google Classroom, and any website.

    Cost / License

    • Free
    • Open Source

    Platforms

    • Google Chrome
    Dyslexia Mode
     
  11. RewritePal icon

    RewritePal

     6 likes

    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.

    18 RewritePal alternatives

    Cost / License

    • Free
    • Open Source (MIT)

    Application types

    Platforms

    • Online
    RewritePal screenshot 1
     
  12. Editsaurus icon

    Editsaurus

     14 likes

    Highlights potential pitfalls in your writing to encourage good habits.

    Cost / License

    • Free
    • Open Source (MIT)

    Application type

    Alerts

    • Discontinued

    Platforms

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

    proselint

     2 likes

    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

    Platforms

    • Linux
    • Python
     
  14. Grammark icon

    Grammark

     2 likes

    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

    Application type

    Platforms

    • Online
    • Self-Hosted
     
    |
    2
    Grammark vs Grammarly Comments
    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.
    • Grammark is Free and Open SourceGrammarly is Freemium and Proprietary
12 of 25 Grammarly alternatives