Optical coding has been widely applied in communication and data processing fields due to its practical and powerful characteristics, such as high transmission rate and operation convenience. However, improvements in the loading information capacity of optical encoders, always cause more energy consumption. It is a challenge to realize an optical encoder that combines energy savings, high bandwidth, and miniaturization. Here, we report both the concept and the demonstration of a perovskite nano-encoder with an 84% energy-saving efficiency and a tuneable bandwidth up to 200 GHz. The way to code the radiative dynamics of the light source could reduce the unnecessary energy consumption from the initial stage through the control of radiation core. Moreover, the miniature encoder generates code sequences of good coherence, stimulating the development of perovskite-based optical microchips for ultrafast information processing.