Insomnia is a sleep disorder characterized by clinically significant distress caused by difficulty in initiating or maintaining sleep, or early-morning awakening. By definition, insomnia must affect important areas of functioning and occur more than three nights per week for at least 3 months. Insomnia is highly prevalent, with a high relapse rate and a tendency to become chronic. Therefore, the demand for insomnia treatment is high. The current first-line treatment recommended for insomnia is cognitive behavioral therapy for insomnia (CBTi). Conventional CBTi is a multicomponent intervention program that includes: 1) a behavioral component made up of stimulus control therapy, sleep restriction therapy, and muscle relaxation; 2) a cognitive component; and 3) an educational component focused on sleep hygiene. Despite considerable evidence of CBTi efficacy, accessibility and cost remain major barriers. Recently, internet-delivered digital CBTi (dCBTi) has emerged as a potential answer for the growing demand and poor treatment accessibility. This review will discuss the history of CBTi as a first-line treatment for insomnia, the current status and limitations of CBTi, the efficacy of dCBTi as an alternative, and the future of dCBTi in pioneering digital therapeutics.