AI Grammar Check is a mobile app that uses the ChatGPT API to help users improve their writing. It detects and fixes grammar, spelling, and punctuation errors, rephrases text for clarity and impact, and translates content into multiple languages. The app also includes a dictionary for quick word lookups and provides detailed explanations for each correction, helping users learn from their mistakes. With iCloud sync, it works seamlessly across iPhone, iPad, and Mac, making it a versatile tool for students.