Grammarly vs LanguageTool: pricing, features and which to choose

Grammarly is a writing-assistance product made by Superhuman, the company formerly known as Grammarly. The company says Grammarly was founded in 2009 and serves more than 40 million people and 50,000 organizations. On October 29, 2025, it announced a name change to Superhuman while retaining Grammarly, Coda, Mail, and Superhuman Go as products in the broader suite. Grammarly therefore remains focused on writing support rather than becoming a separate foundation-model vendor. In May 2025, the company announced $1 billion in growth financing from General Catalyst and said revenue had exceeded $700 million. It also announced Coda’s acquisition in January 2025 and an agreement to acquire Superhuman in July 2025, placing Grammarly inside a larger product family.

Grammarly works inside supported applications, websites, browsers, and documents. A typical session involves writing text, reviewing inline spelling and grammar suggestions, and applying recommendations for tone, clarity, fluency, inclusive language, or citation consistency when the plan supports those capabilities. Pro adds full-sentence rewrites, tone adjustment, plagiarism detection, and AI-generated-text detection. Team features include style guides, brand tones, knowledge sharing, snippets, and analytics, helping organizations make writing more consistent. Grammarly says the product works across more than 1 million applications and websites. Docs provides a dedicated writing space, while newer agents can help users draft, revise, research, and receive audience feedback without opening a separate application. This broad coverage is central to its everyday writing-assistance approach.

The main limitation is the need to allow an AI service into many writing contexts. For individual accounts, Product Improvement and Training is enabled by default, although users can opt out. Microsoft Editor and Copilot fit organizations centered on Microsoft 365, while Google Docs with Gemini fits teams working mainly in Google Workspace. LanguageTool and ProWritingAid focus more narrowly on correction and style assistance. Grammarly is a strong choice for people who want correction, rewriting, tone guidance, detection features, and broad application coverage in one service. However, organizations should review account controls and content policies before using it for confidential work. Users seeking an open-source or self-hosted checker may also find Grammarly unsuitable, since the profile identifies it as neither.

LanguageTool is a grammar, spelling, punctuation, style, and paraphrasing service that began as Daniel Naber’s computational-linguistics diploma project in 2003. It later became commercial and Learneo acquired it on April 5, 2023, for undisclosed financial terms. LanguageTool says its browser add-on has more than 2 million active installations, serves more than 150 companies, and improves more than 20 million texts daily. These figures are company claims. The product supports more than 30 languages and remains separate from Learneo’s other writing brands. Its open-source core can run locally or in the cloud. Hosted Premium and AI features are commercial services, giving users a choice between self-managed checking and expanded hosted capabilities for writing, editing, and paraphrasing.

A typical LanguageTool workflow begins in a browser extension, desktop application, mobile application, supported word processor, or the LanguageTool editor. The service identifies spelling, grammar, punctuation, word choice, style, typography, and some contextual issues, then offers suggestions users may accept or reject. Premium adds more than 20,000 additional checks for several major languages, a personal style guide, text statistics, larger fields, and unlimited sentence paraphrasing. Teams add user management, shared style guidance, and a shared dictionary. Developers can submit text through the HTTP API, while organizations can request a commercial API or run the server themselves. This range makes the product applicable to individual writing, managed team workflows, and developer integrations requiring programmatic checking.

LanguageTool suits multilingual checking, open-source deployment, and writing through browsers or word processors. Grammarly is the closer consumer comparison, emphasizing English rewriting and business administration, while QuillBot focuses more heavily on paraphrasing. Microsoft Editor is convenient for Microsoft 365 users, but LanguageTool provides a self-hostable core and public checking API. The public API permits 20 requests per IP per minute, 75 KB of text per IP per minute, and 20 KB per request, while automated requests are prohibited. LanguageTool is therefore most suitable when language coverage, deployment control, or local hosting matters more than a larger proprietary suite. Users needing heavy automated traffic should note the public limits and consider the commercial API or self-hosting instead.