QuillBot

QuillBot carved out a massive niche as a paraphrasing engine long before ChatGPT made generative AI a household phrase. Instead of asking the AI to write something from scratch, you paste an existing paragraph into the left side of the screen, and QuillBot completely rewrites it on the right side, altering the vocabulary and sentence structure while retaining the original meaning. It is overwhelmingly popular in the academic sector. Students use it to simplify complex academic papers they are trying to read, or to help reword their own clunky sentences to flow better. Non-native English speakers rely on it heavily to ensure their emails or essays sound natural, using the "Fluency" mode to iron out awkward phrasing. Recently, they have expanded into a full writing suite, adding a summarizer tool, a grammar checker, and a co-writer document editor. However, the core sliding-scale paraphraser—which lets you click a specific word in the rewritten text to see a dropdown of alternative synonyms—remains its most beloved and frequently used feature, offering a level of manual control that pure generative tools lack.