The widespread utilization of wireless sensor networks for the Internet of Things is heavily restrained due to the lack of a sustainable power source as a replacement of batteries. Scavenging mechanical energy from ubiquitous vibrations through miniaturized electromagnetic transducers has become a potential solution to this powering issue. This work proposes the design and performance analysis of fully integrated MEMS Electromagnetic Vibration Energy Harvesters. Through analytical formulation and thorough finite element analysis, we present a systematic design study to optimize the magnet-coil interaction in a precise location within a small footprint. The compact device topology yielded an electromagnetic coupling as high as 62.9mWb/m with the optimized stripe-shaped micro-magnets and rectangular micro-coils. The nonlinear spring topology demonstrated six times improvement in the half-power bandwidth compared with its linear counterpart, at the cost of reduced power density. The proposed designs can be developed using standard MEMS fabrication methods leveraging the CMOS compatible integration at the system level for potential applications in the Internet of Things.