Miniaturisation of silicon microelectronics continues to be a major driving force for the technological progress in computing and electronics. As modern device fabrication is approaching the nanometre scale, quantum effects are dominating device properties. This may set a lower bound for the size of conventional devices, and therefore ultimately limit their performance. On the other hand, quantum effects could enable the development of new types of devices, which might overcome the limitations of classical physics. This review outlines the recent progress in the field of single-electron devices for charge sensing and metrological applications. It illustrates the gap between large-scale commercial fabrication and research prototypes as well as technologies that could close this gap in the future. Any viable roadmap towards commercialisation of single-electron devices is likely to leverage the highly developed silicon-based fabrication methods that have enabled impressive progress in information and communication technology. The scope of this review ranges from random dopant fluctuations in classical devices to single-dopant transistors, and covers electron pumps as well as top-down fabricated single-electron transistors in direct-current and radio-frequency operation.