An online AI therapist is a digital mental-health tool that provides supportive, therapeutic conversations through artificial intelligence. Accessible from any device with an internet connection, an online AI therapist offers a private, judgment-free space where users can talk about stress, anxiety, low mood, relationships, or daily challenges. These systems use natural language processing and evidence-based methods such as cognitive behavioral therapy (CBT), mindfulness, and grounding techniques to deliver practical coping strategies and emotional guidance.