Abstract: The rapid adoption and development of electric vehicle (EV) networks has required the expansive deployment of EV charging infrastructure (EVCI) which relies on communication protocols such as the open charge point protocol (OCPP) to coordinate data transfer between charging network operators and the EV supply equipment. In this paper, we present EVSEFuzz, a tool for automatically building fuzzers to test the security of protocol implementations. To achieve this we make a novel use of Python datatype validation packages and tools to ``understand'' datatypes and message structures and generate both compliant and non-compliant messages. To date, EVSEFuzz has been tested successfully with several open and closed-source implementations and has found several vulnerabilities leading to the publication of two CVEs.