Top 10 Open Source Alternatives to Grammarly in 2025: A Comprehensive Comparison

Grammarly has long been a go-to tool for improving writing, but the rise of open-source alternatives provides users with a variety of free, customizable options. Here, we explore the top 10 open-source alternatives to Grammarly in 2025, each offering unique features and capabilities.

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1. LanguageTool

Description: LanguageTool is a sophisticated open-source proofreading program that identifies errors that standard spell checkers often miss. It offers grammar, style, and spelling checks in multiple languages.
Key Features:
Multi-Language Support: Supports over 20 languages, including English, Spanish, French, German, and more.
Error Detection: Finds grammatical, stylistic, and spelling errors.
Integration: Offers browser extensions (Chrome, Firefox, etc.) and integrations with LibreOffice, Google Docs, and Microsoft Word.
API Access: Can be integrated into other software or websites via an API.
Customization: Includes a personal dictionary and allows for custom style rules. Learn more about LanguageTool

2. Grammalecte

Description: Grammalecte is an open-source grammar checker, specifically designed for the French language.
Key Features:
French Language Focus: Specifically targets French grammar, spelling, and style.
Multiple Dictionaries: Includes four selectable dictionaries for spell checking.
Verb Conjugation: Provides a tool for conjugating approximately 8,000 verbs.
Text Formatting: Offers automatic text formatting
Lexicographer Tool: Includes a tool for lexicography Explore Grammalecte

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3. CorrectLy

Description: CorrectLy is an NLP based spelling and grammar correction tool that corrects articles and raw text.
Key Features:
NLP Based: Uses natural language processing to identify errors.
Spelling Correction: Corrects spelling mistakes.
Grammar Correction: Corrects grammatical errors.
Raw Text Support: Accepts raw text as input.
Article Support: Accepts articles as input. Discover CorrectLy

4. After the Deadline

Description: After the Deadline is an open-source technology that uses AI and natural language processing to detect grammar, spelling, and style errors.
Key Features:
AI-Powered: Uses artificial intelligence to find errors.
Contextual Spelling Checks: Detects misused words based on context.
Multiple Integrations: Available as a plugin/add-on for WordPress and other online platforms.
Free to Use: Available for free.
Open-Source: Code is publicly available. Explore After the Deadline

5. Slick Write

Description: Slick Write is a free application that checks your writing for grammar, potential stylistic mistakes, and other features of interest.
Key Features:
Free Tool: Completely free to use.
Grammar Check: Checks for grammatical errors.
Style Check: Checks for stylistic errors.
Reporting and Statistics: Provides reports and statistics on writing.
Text Editor: Includes a text editor for composing. Learn more about Slick Write

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6. Writing Tools

Description: An open-source application that is similar to Apple intelligence's writing tool for Windows.
Key Features:
Windows Support: Designed specifically for Windows.
Text Manipulation: Allows the user to manipulate text.
Shortcut Activation: Activated using shortcuts.
Multiple Options: Offers various options to improve writing.
Open-Source: Code is publicly available. Discover Writing Tools

7. UniJump

Description: UniJump is an open-source widget that seamlessly integrates with ChatGPT to enhance writing.
Key Features:
ChatGPT Integration: Integrates directly with ChatGPT for AI writing assistance.
Free and Open Source: 100% free and open source.
No Sign-Up: No sign-up is needed.
Security Focused: Emphasizes user security and data privacy.
Customizable: Allows users to contribute to the code. Explore UniJump

8. Flyspell (Emacs)

Description: Flyspell is a minor mode in the Emacs text editor that provides on-the-fly spell checking.
Key Features:
Real-time Spell Check: Underlines misspelled words in real time.
Autocorrect Option: Offers an option to autocorrect words.
Emacs Integration: Seamlessly works within the Emacs text editor.
Customizable: Highly customizable within Emacs.
Open Source: Part of the Emacs open-source ecosystem. Learn more about Flyspell

9. Scribbr Grammar Checker

Description: A free grammar checker that corrects spelling, grammar, and punctuation mistakes.
Key Features:
Multiple Language Support: Supports English, Spanish, French, and German.
Free to Use: Available for free.
Simple Interface: Simple and easy to use interface.
One Click Fix: Can fix mistakes with one click.
No Sign-Up: No sign-up is needed. Discover Scribbr Grammar Checker

10. Grammar Checker

Description: A free open-source tool that is updated regularly to give the best possible results.
Key Features:
Free to Use: Available for free.
Regular Updates: Updated regularly.
Multiple Checks: Provides Grammar, punctuation, spelling, and style checks.
Plagiarism Detection: Includes a plagiarism detection feature.
Open Source: Code is publicly available. Learn more about Grammar Checker

These tools offer a range of options for writers looking for open-source alternatives to Grammarly, each with its own strengths and focus areas.

Disclaimer: Please note that while I've done my best to gather accurate information, the features and availability of these tools may change. Always refer to the official websites or repositories for the most up-to-date details.

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FAQ

1. What is LanguageTool and what features does it offer?

LanguageTool is a sophisticated open-source proofreading program that identifies errors in multiple languages. It supports over 20 languages, offers grammar, style, and spelling checks, integrates with various platforms, provides API access, and allows for custom style rules. Explore LanguageTool

2. Is there a reliable open-source grammar checker for French?

Yes, Grammalecte is specifically designed for French grammar. It includes four selectable dictionaries, a verb conjugation tool for approximately 8,000 verbs, automatic text formatting, and a lexicographer tool. Learn more about Grammalecte

3. How does CorrectLy enhance article and text correction?

CorrectLy uses natural language processing to correct spelling and grammar in raw text and articles. More about CorrectLy

4. What is After the Deadline and its key features?

After the Deadline is an AI-driven open-source technology for detecting grammar, spelling, and style errors. It includes contextual spelling checks and integrates with WordPress and other online platforms. Explore After the Deadline

5. What does Slick Write offer to its users?

Slick Write is a free tool that checks writing for grammatical and stylistic mistakes, with features including a text editor and detailed writing reports and statistics. Learn more about Slick Write

6. Are there any open-source writing tools similar to Apple Intelligence for Windows?

Yes, Writing Tools is designed for Windows with features like text manipulation, shortcut activation, and various writing improvement options. Discover Writing Tools

7. How does UniJump enhance writing with ChatGPT integration?

UniJump seamlessly integrates with ChatGPT for AI-driven writing assistance, is free and open-source, requires no sign-up, and prioritizes user security and data privacy. Explore UniJump

8. What is Flyspell and how does it function?

Flyspell is a minor mode in Emacs that provides real-time spell checking underlining misspelled words, offering an autocorrect option, and is highly customizable within Emacs. Learn more about Flyspell

9. Can a free grammar checker cover multiple languages?

Yes, the Scribbr Grammar Checker supports English, Spanish, French, and German, offering spelling, grammar, and punctuation checks with a simple interface and no sign-up requirement. More about Scribbr Grammar Checker

10. What is the Grammar Checker tool known for?

Grammar Checker is a free, regularly updated open-source tool that provides grammar, punctuation, spelling, style checks, and plagiarism detection. Learn more about Grammar Checker

References

About the Author

Violetta Bonenkamp, also known as MeanCEO, is an experienced startup founder with an impressive educational background including an MBA and four other higher education degrees. She has over 20 years of work experience across multiple countries, including 5 years as a solopreneur and serial entrepreneur. She’s been living, studying and working in many countries around the globe and her extensive multicultural experience has influenced her immensely.

Violetta is a true multiple specialist who has built expertise in Linguistics, Education, Business Management, Blockchain, Entrepreneurship, Intellectual Property, Game Design, AI, SEO, Digital Marketing, cyber security and zero code automations. Her extensive educational journey includes a Master of Arts in Linguistics and Education, an Advanced Master in Linguistics from Belgium (2006-2007), an MBA from Blekinge Institute of Technology in Sweden (2006-2008), and an Erasmus Mundus joint program European Master of Higher Education from universities in Norway, Finland, and Portugal (2009).

She is the founder of Fe/male Switch, a startup game that encourages women to enter STEM fields, and also leads CADChain, and multiple other projects like the Directory of 1,000 Startup Cities with a proprietary MeanCEO Index that ranks cities for female entrepreneurs. Violetta created the "gamepreneurship" methodology, which forms the scientific basis of her startup game. She also builds a lot of SEO tools for startups. Her achievements include being named one of the top 100 women in Europe by EU Startups in 2022 and being nominated for Impact Person of the year at the Dutch Blockchain Week. She is an author with Sifted and a speaker at different Universities. Recently she published a book on Startup Idea Validation the right way: from zero to first customers and beyond and launched a Directory of 1,500+ websites for startups to list themselves in order to gain traction and build backlinks.

For the past several years Violetta has been living between the Netherlands and Malta, while also regularly traveling to different destinations around the globe, usually due to her entrepreneurial activities. This has led her to start writing about different locations and amenities from the POV of an entrepreneur. Here’s her recent article about the best hotels in Italy to work from.

About the Publication

Fe/male Switch is an innovative startup platform designed to empower women entrepreneurs through an immersive, game-like experience. Founded in 2020 during the pandemic "without any funding and without any code," this non-profit initiative has evolved into a comprehensive educational tool for aspiring female entrepreneurs.The platform was co-founded by Violetta Shishkina-Bonenkamp, who serves as CEO and one of the lead authors of the Startup News branch.

Mission and Purpose

Fe/male Switch Foundation was created to address the gender gap in the tech and entrepreneurship space. The platform aims to skill-up future female tech leaders and empower them to create resilient and innovative tech startups through what they call "gamepreneurship". By putting players in a virtual startup village where they must survive and thrive, the startup game allows women to test their entrepreneurial abilities without financial risk.

Key Features

The platform offers a unique blend of news, resources,learning, networking, and practical application within a supportive, female-focused environment:

Skill Lab: Micro-modules covering essential startup skills
Virtual Startup Building: Create or join startups and tackle real-world challenges
AI Co-founder (PlayPal): Guides users through the startup process
SANDBOX: A testing environment for idea validation before launch
Wellness Integration: Virtual activities to balance work and self-care
Marketplace: Buy or sell expert sessions and tutorials

Impact and Growth

Since its inception, Fe/male Switch has shown impressive growth:

3,000+ female entrepreneurs in the community
100+ startup tools built
5,000+ pieces of articles and news written

Partnerships

Fe/male Switch has formed strategic partnerships to enhance its offerings. In January 2022, it teamed up with global website builder Tilda to provide free access to website building tools and mentorship services for Fe/male Switch participants.

Recognition

Fe/male Switch has received media attention for its innovative approach to closing the gender gap in tech entrepreneurship. The platform has been featured in various publications highlighting its unique "play to learn and earn" model.