OCPP (Open Charge Point Protocol)

OCPP lets any compliant charger work with any compliant management back end: starting and stopping sessions, authorizing users, reporting meter values, pushing firmware updates and diagnostics, and controlling charging power remotely ("smart charging") to stay within site limits or respond to grid signals. Version 1.6 remains widespread; 2.0.1 adds stronger security and device management; and OCPP has been published by the IEC as IEC 63584.

For charger makers, OCPP avoids lock-in and is often required by site owners and incentive programs. For sites, smart charging lets more chargers share limited electrical capacity.

Where it bites: implementations differ in which optional features they support, so interoperability must be tested against the back ends customers actually use; the Open Charge Alliance runs a certification program.