Grammarly is an American English-language writing assistant software tool. It started as a tool to review the spelling, grammar, and tone of a piece of writing and to identify possible instances of plagiarism. Since 2025, it has integrated extensive generative AI tools, including options to generate essays from scratch, to suggest and insert citations, to "humanize" the text to avoid it being flagged as AI-generated, and to predict grades based on user input on the instructor, course, and university. It can also make stylistic and tonal recommendations. An "Expert review" feature, which attributed Grammarly's editing suggestions to subject-matter experts in various fields, was discontinued in March 2026 due to criticism and complaints.
Grammarly was developed in Ukraine and launched in 2009 by Alex Shevchenko, Max Lytvyn, and Dmytro Lider. In 2024 Grammarly bought Coda, and Coda CEO Shishir Mehrotra became Grammarly's CEO. After buying Superhuman in 2025, Grammarly rebranded its parent company as Superhuman and integrated more generative AI tools in the product. Grammarly is now developed by Superhuman Platform Inc., which is headquartered in San Francisco and has offices in Kyiv, New York, and Vancouver. It is available as a standalone application; a browser extension for Chrome, Safari, and Firefox; and as an add-on for Google Docs.
History
Grammarly was founded in 2009 by Max Lytvyn, Alex Shevchenko, and Dmytro Lider. The company initially offered a subscription-based product intended to help students improve their grammar and spelling. That product was subsequently developed into a writing assistant that checks the grammar, spelling, and tone of a piece of writing.
By 2015, Grammarly had a million active daily users, and began offering its flagship product via a freemium model that allowed all users access to the product's basic capabilities while placing more sophisticated features like style recommendations and plagiarism detection behind a paywall. It also launched a browser extension for Chrome, Safari, and Firefox, as well as an add-on for Google Docs.
In 2019, Grammarly added a tone detector to its writing assistant. This tool uses set rules and Machine learning to help users gauge the character of their writing and tailor it to a particular audience. Also in 2019, the company held a second funding round, raising $90 million. In 2020, Grammarly made its first investment in an outside company, participating in a $10 million funding round for Docugami, a company working on AI-driven document generation.
After the 2022 Russian invasion of Ukraine, Grammarly ceased all business operations in Russia and Belarus. It also continued to pay the salaries of Ukrainians who left their jobs at Grammarly to join the nation's army.
In April 2023, Grammarly launched a product using Generative AI built on the GPT-3 Large language models. In September 2024, Grammarly announced the release of its Authorship tool, which attempts to identify the source of a passage of text. It then designates the passage as written by the text's author, lifted from another source, or generated by AI. It is not clear to what extent such tools work.
In December 2024, Grammarly announced that it was acquiring the productivity startup Coda. As part of the deal, Coda CEO Shishir Mehrotra replaced Rahul Roy-Chowdhury as Grammarly's CEO.
2025 saw major changes in Grammarly's funding, leadership, and product. In May, Grammarly announced it raised $1 billion in nondilutive funding from General Catalyst. In July, Grammarly announced that it was acquiring the email client Superhuman. In October, Grammarly's parent company, Grammarly Inc., announced a rebrand to the Superhuman brand.
In March 2026, Grammarly faced complaints and criticism in response to an AI-powered feature called "Expert Review", which offered writing advice from simulations of actual living and deceased authors without contacting them or getting their permission. Launched in August 2025 as part of a suite of AI-powered features, the tool's featured authors included Stephen King, Neil deGrasse Tyson, Carl Sagan, and bell hooks. On March 11, 2026, the same day that journalist Julia Angwin filed a federal class-action lawsuit against the company, Superhuman announced that it was discontinuing the feature.
Vulnerabilities
In early 2018, Tavis Ormandy, a security researcher at Google who was formerly part of Google's Project Zero team, discovered a severe vulnerability in Grammarly's browser extension that exposed authentication tokens to websites and could allow them to access the users' documents and other data. A few hours later, the company released a hotfix and reported that it found no evidence of compromised user data. This vulnerability was registered as CVE-2018-6654 in the Common Vulnerabilities and Exposures database. In December 2018, Grammarly launched a bug bounty program on HackerOne, offering a $100,000 reward to the first white hat hacker to access a specific document on the company's server.
Reception
Reviewers have praised Grammarly's ease of use and helpful suggestions, finding it worthwhile despite its relatively high price and lack of offline functionality. Conversely, some users have criticized Grammarly for incorrect suggestions, ignorance of tone and context, and reduction of writers' freedom of expression.
Documents that Grammarly has corrected have occasionally been accused by detection engines such as Turnitin of being partially or entirely AI-generated. Schools are struggling to develop consistent and fair rules for its use, with some teachers recommending Grammarly to their students and others rejecting it.
Superhuman Platform Inc.
Grammarly is developed by Superhuman Platform Inc., a technology company that also develops productivity, AI, and SaaS products such as Superhuman Mail, Coda, and Superhuman Go. The company assumed its current form in 2025, when Grammarly Inc., which was founded in 2009, acquired Superhuman Mail and Coda and rebranded itself as Superhuman. The company is headquartered in San Francisco, California and led by CEO Shishir Mehrotra.
In February 2026, Superhuman announced the acquisition of Rows, a company that uses AI to manage data and spreadsheets. Superhuman said that it would use Rows to improve the capabilities of Coda.
Investments
As of May 2017, Grammarly had raised over $110 million in a public funding round, surpassing all previous Ukrainian startups. In 2019, the company raised $90 million in investment and was valued at over $1 billion. The total amount of investment raised in 2019 was $200 million.
On 13 May 2020, Grammarly announced its first investment in the Seattle-based start-up Docugami. The investment was made as part of the company's seed funding round.
In November 2021, the company announced that it had raised a new round of investment worth $200 million at a total valuation of $13 billion. New investors included Baillie Gifford, a Scottish investment firm, and funds managed by BlackRock. The company's valuation had grown significantly from its earlier rounds, reflecting the increasing demand for AI-powered writing tools.
Technology and Features
Grammarly's core technology relies on Artificial intelligence and Natural language processing techniques to analyze text. The system uses a combination of rule-based algorithms and Deep learning models to identify grammatical errors, spelling mistakes, and stylistic issues. Over time, the company has integrated more advanced Neural network architectures, including Transformer (architecture) models, to improve the contextual understanding of language.
One of the key features is the tone detector, which uses Machine learning to assess the emotional character of writing. The tool provides suggestions for adjusting tone to match the intended audience, such as making text more formal, friendly, or confident. Additionally, Grammarly's plagiarism detection scans documents against a vast database of web pages and academic publications to identify potential instances of unoriginal content.
Since 2025, Grammarly has expanded its generative AI capabilities, allowing users to generate essays from scratch, insert citations, and even predict grades based on input about the instructor, course, and university. The "humanize" feature aims to make AI-generated text appear more natural to detection systems, though its effectiveness is debated. These tools are built on Large language models and are continuously updated to improve accuracy and relevance.
Corporate Structure and Leadership
Grammarly's parent company, Superhuman Platform Inc., is headquartered in San Francisco, California, with offices in Kyiv, New York, and Vancouver. The company operates as a technology firm focused on productivity and AI-driven solutions. Under the leadership of CEO Shishir Mehrotra, who took over in December 2024, the company has pursued a strategy of acquisitions and product integration.
The acquisition of Coda in 2024 brought a collaborative document platform into the Grammarly ecosystem. The subsequent acquisition of Superhuman in 2025 added a premium email client, and the rebranding to Superhuman reflected the company's broader ambitions beyond just writing assistance. The integration of these products aims to create a unified suite of tools for productivity and communication.
The company has also maintained a strong presence in Ukraine, where it was originally founded. Despite the ongoing conflict, Grammarly has continued to support its Ukrainian employees and has ceased operations in Russia and Belarus as a result of the 2022 invasion. This commitment to its roots has been a notable aspect of its corporate identity.
Future Outlook
As of 2026, Grammarly continues to evolve its product offerings, with a focus on integrating Generative AI across its platforms. The company faces challenges related to user trust, particularly after the discontinuation of the "Expert Review" feature and the associated legal issues. However, its substantial funding and strategic acquisitions position it for further growth in the competitive AI writing assistant market.
The broader adoption of AI in education and professional settings presents both opportunities and risks for Grammarly. While many users appreciate the convenience and efficiency of AI-assisted writing, concerns about authenticity and academic integrity remain. Grammarly's ability to navigate these issues while maintaining product quality will likely determine its long-term success.