Extremely intense light pulses generated by free-electron lasers (FELs) are versatile tools in research. Particularly in the X-ray range, they can be deployed to analyze the details of atomic structures of a wide variety of materials and to follow fundamental ultrafast processes with great precision. Until now, FELs such as the European XFEL in Germany are based on conventional electron accelerators, which make them long and expensive. An international team has now achieved a breakthrough on the way to an affordable alternative solution: they were able to demonstrate seeded FEL lasing in the ultraviolet regime based on a still young technology — laser-plasma acceleration. In the future, this might allow to build more compact systems, which would considerably expand the possible applications of FELs.