Autism is a neurodevelopmental disorder that affect various parts of brain in a child and uncurable last throughout life. Abnormal facial expression, body posture, poor eyesight, behavior and learning disability are the common symptoms of autism. Internet of things (IoT) emerges as a revolutionary tool for early autism diagnosis enables real time monitoring, uninterrupted data exchange and automatic analysis and help in achieving sustainable goals. Early intervention may improve quality of life of autistic individuals. IoT diagnose early symptoms of autism by utilizing interconnected system, sensors, wearable sensors, and cloud data analysis to observe developmental and characteristics patterns in children. These systems simplify seamless data collection and provide give actionable perception via latest processing technology. This paper focuses on IoT based tools for early autism diagnosis, data privacy, their integration with machine learning and user-friendliness. Additionally, fulfill the gap between traditional observation and real-world behaviors, access individual and transformative solutions.