Formaldehyde (FA) is a reactive toxic volatile organic compound (VOC), produced both exogenously from the environment and endogenously within most organisms, and poses significant health risks to humans at elevated concentrations. Consequently, the development of reliable and sensitive FA sensing technologies is crucial for environmental monitoring, industrial safety, and public health protection. This review will provide a concise overview of FA sensing methodologies, highlighting key principles, sensing mechanisms, and recent advancements. The main aim of this review article is to comprehensively discuss recent advancements in FA sensors utilizing small molecules, nanoparticles, organic materials, and polymers, along with their successful applications across various fields, with particular emphasis on
in situ
FA sensing using polymeric probes due to their advantages over small molecular probes. Additionally, it will discuss prospects for future design and research in this area. We anticipate that this article will aid in the development of next-generation polymeric FA sensing probed with improved physicochemical properties.