Spiders (order Araneae) have developed a range of unique and effective adaptations as a result of their diverse predation strategies. Based on the latter, they can be placed into one of three major functional groups: wanderers, ambush hunters, and web weavers. Here, we detail key biological facets of species in these groups and draw upon this information to present a number of innovative bioinspired research directions. More specifically, we focus on spider vision, locomotion, mechanoreceptors, deceptive signals, and silk. The telescope-like eyes of jumping spiders are particularly effective in detecting stimuli over long distances. Furthermore, the retinas of their large anterior median eyes contain multiple layers of packed photoreceptors that are each sensitive to different wavelengths of light and that can analyse polarised light. Optics researchers have drawn upon jumping spider eye structure to develop several kinds of high-resolution nano- and microcameras. Spider locomotion relies on a hydrostatic skeleton, unique leg angulation patterns, and dry adhesion via scopulae, mechanisms that can all inform the design of spider-like robots. Spiders possess leg mechanoreceptors that are stimulated by airflow, proximal low-frequency sounds, direct touch, olfactory signals, or proprioceptive input, which could inspire the development of application-driven artificial flow-sensing hairs. UV reflectance is a deceptive signal commonly used by spiders and could be employed in novel miniature light-dispersive components. Because of its many unique biochemical and biomechanical properties, spider silk is being used in numerous bioinspired solutions under development, including in novel medical and technological applications.