GrammarBot

GrammarBot is a free, browser-based writing analysis tool that checks text for grammar and spelling errors using the open-source LanguageTool engine. Beyond basic proofreading, it scores readability with five established formulas — Flesch Reading Ease, Flesch-Kincaid, SMOG, Coleman-Liau, and Dale-Chall — and reports tone and sentiment, including formality level and emotional cues. It also runs a lightweight SEO content check that measures keyword density, and surfaces vocabulary metrics such as lexical diversity and complex-word counts, along with estimated reading and speaking times. Users paste up to 50,000 characters directly into the browser; the site states that analysis runs client-side and no text is sent to a server, which suits anyone who wants a quick check without creating an account. GrammarBot is aimed at writers, bloggers, and content marketers who want a fast, no-signup way to gauge the quality and readability of a draft rather than a full proofreading suite. There is no paid tier: the site is entirely free, supported by affiliate links and advertising rather than subscriptions. Its scope is narrower than dedicated writing assistants — it flags issues and metrics but does not offer AI-generated rewrites or style coaching, so writers who want suggested phrasing changes will need a separate tool.