For millennia, ceramics have been densified via sintering in a furnace, a time-consuming and energy-intensive process. The pressing need to minimize environmental impact in conjunction with economic demands invite to overcome the concept of using large kilns relying on thermal radiation and insulation. Ideally, energy is channeled directly into the ceramic allowing ultra-fast processes with the key challenge of effectively transmitting power with low losses. Here, we realize ultra-rapid heating by absorption of frequency-adapted electromagnetic radiation in the ceramic itself. With accurately controlled visible and UV-light as energy source, bulk ceramics are sintered within seconds and with outstanding efficiency (≈2 kWhkg^-1) independent of batch size. Moreover, agile temperature control through light allows highly accurate spatial and temporal evolution giving novel design opportunities. We demonstrate this technique for ceramics needed for energy storage and conversion, in electronic and structural applications. With sintering accelerated by a factor of more than one hundred, vastly improved flexibility and the opportunity to save up to 2.5 tons of CO₂ per ton of ceramic, it provides the opportunity to cater to twenty-first-century needs in ceramic synthesis.