This book features a collection of high-quality research papers presented at the 12th International Symposium on Applied Computing for Software and Smart systems (ACSS 2025), held on July 4-5, 2025, in Kolkata, India. The book presents innovative works by undergraduate, graduate students as well as Ph.D. scholars. The emphasis of the workshop is on software and smart systems and research outcomes on other relevant areas pertaining to advancement of computing.