Studying interaction of solvated ions with interfaces and their transport inside ionic devices has been a recurrently hot topic for research at the interface of physics, chemistry, and processing technologies. Iontronics, in a general use of this term, concern systems in which dissolved ions such as Na+, Cl-, and Ca2+ get transported. The driving force in iontronics is not necessarily electric or diffusive, but sometimes also convective due to fluid flows. The coupling between charge and fluid transport has found a wide range of applications, from signal transduction to energy generation or storage. The breadth and diversity of iontronic concepts, however, has been studied in parallel scientific tracks. To create opportunities for cross-fertilization between these tracks, this Faraday Discussion will be an opportunity to present the most recent experimental, theoretical, and numerical methods in the field, to review some of the existing challenges, both in fundamental research (e.g. understanding nanoscale ion transport) and in industrial applications (e.g. membrane technology, energy storage, imaging at the nanoscale), and to strengthen synergetic interactions between researchers addressing the microscopic and device-level mechanisms involved in these very pressing problems.