OCPP 1.6J Protocol Reference
The complete technical reference for the Open Charge Point Protocol, version 1.6J. All 28 messages documented from the official Open Charge Alliance specification.
What is OCPP?
The Open Charge Point Protocol (OCPP) is a free, open communication standard maintained by the Open Charge Alliance (OCA). It defines how EV chargers (Charge Points) talk to management software (a Central System) over a network connection.
OCPP 1.6J uses WebSocket with JSON payloads. A charger connects to a Central System URL, and both sides exchange structured messages: the charger reports its status, meter readings, and transaction events, while the Central System sends commands like starting sessions, updating firmware, or adjusting charging profiles.
Because OCPP is an open standard, any charger that supports it can connect to any compatible Central System. This prevents vendor lock-in and gives operators the freedom to mix hardware from different manufacturers under a single management platform.
Further reading
What is OCPP?
OCPP stands for Open Charge Point Protocol. It's the language of EV chargers.
How OCPP Came to Dominate EV Charging
Where it came from, why it spread, and what the U.S. rule angle really means.
What is an OCPP Backoffice?
An OCPP Backoffice is a database in which you can see your chargers and check how they're doing.
OCPP? Plugchoice.
Plugchoice is a free charger management platform that acts as an OCPP Central System. Connect any OCPP-compatible charger and manage it through our web portal, mobile app, or REST API.
We support the full OCPP 1.6J specification, including Smart Charging profiles for load balancing and solar integration. Hardware-agnostic, no lock-in, no subscription fees for core features.
Protocol Reference
All 28 OCPP 1.6J messages organized by feature profile. Each message shows direction, required and optional fields, types, and valid enum values.
Core
Required. Fundamental charge point operations: authorization, transactions, status reporting, configuration, and basic remote control.
Firmware Management
Firmware updates and diagnostics upload for remote maintenance of charge points.
Local Auth List
Manage a local authorization cache on the charge point for offline authentication.
Reservation
Reserve a connector for a specific user ahead of time.
Smart Charging
Set and manage charging profiles for load balancing, solar integration, and scheduled charging.
Remote Trigger
Request the charge point to send a specific message on demand.