IsGPT (isgpt.org) is a free AI content detector incubated by MIT CSAIL. It identifies text generated by ChatGPT, Gemini, Claude and other AI models using perplexity and burstiness analysis. Supports 200+ languages, protects user privacy (no original text stored), and includes a "Remove AI" feature to make content sound more natural. Useful for educators, researchers, and content reviewers.