QuillBot Paraphraser is the flagship tool of QuillBot's comprehensive AI writing suite and one of the most widely used writing tools on the internet, with over 35 million users and a 4.7-star Chrome extension rating from 5 million installs. At its core, QuillBot rephrases text while preserving original meaning, functioning like an intelligent sentence-level thesaurus that understands context. Users choose from 10+ paraphrasing modes: Standard, Fluency, Formal, Simple, Creative, Academic, Expand, Shorten, Humanize, and Custom, to reshape tone and structure for any purpose. A Synonym Slider controls the degree of vocabulary change from subtle refinements to sweeping rewrites. Clicking any word reveals AI-powered synonym suggestions for granular editing. QuillBot supports paraphrasing in 20+ languages, accepts everything from single sentences to full document uploads, and tracks structural changes with before-and-after comparison statistics. Beyond paraphrasing, QuillBot has grown into a complete writing platform: Grammar Checker for error correction, Plagiarism Checker against billions of sources, AI Detector for identifying AI-generated content, Summarizer for condensing long texts, Citation Generator (APA, MLA, Chicago), Translator for 20+ languages, AI Chat, AI Image Generator, PDF Editor, Speech-to-Text, Text-to-Speech, AI Website Builder, and more. Whether you are a student rewriting an essay, a content writer refreshing blog posts, a professional polishing communications, or a non-native speaker improving fluency, QuillBot gives you complete control over how your writing sounds without changing what it means.