Polydopamine (PD) is a versatile surface coating method inspired by the adhesive properties of mussel proteins. Since its discovery in 2007, PD has been widely used for surface modification due to its simplicity, adaptability, and broad applicability across various fields. This review summarizes the development of PD over the past decade, highlighting its unique properties, coating methods, and emerging applications. PD coatings are formed through the oxidative polymerization of dopamine, resulting in a material-independent surface chemistry that can be tailored for various functions. The coating process is simple, involving immersion of a substrate in an alkaline dopamine solution, and can be enhanced with chemical oxidants, external stimuli, or one-pot methods to improve efficiency and control. PD coatings exhibit chemical reactivity, enabling further functionalization with molecules containing nucleophilic groups, and can be used for applications such as cell culture, drug delivery, antimicrobial surfaces, and energy storage. The versatility of PD is further expanded through the use of dopamine derivatives, nitrogen-free polyphenolic precursors, and improved mechanical properties. Despite its advantages, challenges remain in enhancing the mechanical robustness of PD coatings and expanding their use to more chemically diverse building blocks. Future research aims to address these challenges and further expand the applications of PD coatings in biomedical, energy, and other fields.Polydopamine (PD) is a versatile surface coating method inspired by the adhesive properties of mussel proteins. Since its discovery in 2007, PD has been widely used for surface modification due to its simplicity, adaptability, and broad applicability across various fields. This review summarizes the development of PD over the past decade, highlighting its unique properties, coating methods, and emerging applications. PD coatings are formed through the oxidative polymerization of dopamine, resulting in a material-independent surface chemistry that can be tailored for various functions. The coating process is simple, involving immersion of a substrate in an alkaline dopamine solution, and can be enhanced with chemical oxidants, external stimuli, or one-pot methods to improve efficiency and control. PD coatings exhibit chemical reactivity, enabling further functionalization with molecules containing nucleophilic groups, and can be used for applications such as cell culture, drug delivery, antimicrobial surfaces, and energy storage. The versatility of PD is further expanded through the use of dopamine derivatives, nitrogen-free polyphenolic precursors, and improved mechanical properties. Despite its advantages, challenges remain in enhancing the mechanical robustness of PD coatings and expanding their use to more chemically diverse building blocks. Future research aims to address these challenges and further expand the applications of PD coatings in biomedical, energy, and other fields.