An alternative approach to discrete quantum bits is to use a large number of states of a harmonic oscillator to encode the values 0 and 1 of a logical qubit into complex superpositions of harmonic states. This approach is referred to as continuous-variable quantum computing. We explore continuous variable quantum computing in 3d- and planar microwave resonators. Our superconducting 3d cavities provide state-of-the-art quality factors and long-living photon states allowing us to encode quantum information in multi-photon states. This makes it possible to implement hardware-efficient quantum error correction while keeping the noise channels limited. We are currently actively investigating these directions.