OCPP (Open Charge Point Protocol) is an open communication standard that defines how electric vehicle (EV) charging stations communicate with central management systems (CSMS). Developed and maintained by the Open Charge Alliance (OCA), OCPP enables interoperability between chargers from different manufacturers and any backend platform.
As of 2025, OCPP is deployed on millions of charge points worldwide and is supported by every major EV charger manufacturer including ABB, EVBox, Wallbox, Alfen, Schneider Electric, and Tritium.
Why OCPP Matters
Before OCPP, every charger manufacturer used proprietary protocols. This meant:
- Vendor lock-in: You could only use one manufacturer's backend with their chargers
- No interoperability: Mixing charger brands in a network was impossible
- High integration costs: Every new charger model required custom development
- Slow innovation: Closed systems limited feature development
OCPP solves all of these problems by providing a standardized, open communication layer.
How OCPP Works
OCPP uses a client-server model over WebSocket connections:
- Charge Point (Client): The physical EV charger initiates the WebSocket connection
- CSMS (Server): The Central System (also called CPMS or backend) accepts the connection
- Messages: Both sides exchange JSON or SOAP messages for operations like starting/stopping charging, sending meter values, and firmware updates
Message Types
| Type | Direction | Example |
|---|---|---|
| Request | Charger → CSMS | BootNotification, StatusNotification, MeterValues |
| Request | CSMS → Charger | RemoteStartTransaction, Reset, UpdateFirmware |
| Response | Both directions | Confirmation or error for each request |
OCPP Versions Compared
OCPP 1.6 (JSON/SOAP)
Released in 2015, OCPP 1.6 is the most widely deployed version. Key features:
- Smart Charging: Basic load management profiles
- Remote Operations: Start/stop transactions, reset, unlock connector
- Diagnostics: Upload logs, firmware update
- Authorization: Local and remote ID tag management
- Transport: WebSocket (JSON) or SOAP
OCPP 2.0.1
Released in 2020, OCPP 2.0.1 is the latest major version with significant improvements:
- Device Model: Comprehensive charger configuration management
- ISO 15118 Support: Plug & Charge and vehicle-to-grid capabilities
- Enhanced Security: TLS profiles, signed firmware updates, secure boot
- Transaction Handling: Improved transaction lifecycle with better error recovery
- Display Messages: Control charger screen content remotely
- Cost Information: Real-time pricing and cost updates
| Feature | OCPP 1.6 | OCPP 2.0.1 |
|---|---|---|
| Transport | WebSocket/SOAP | WebSocket only |
| Security | Basic | TLS profiles, signed updates |
| ISO 15118 | No native support (possible via DataTransfer) | Full support |
| Smart Charging | Basic profiles | Advanced composites |
| Device Management | Limited | Comprehensive device model |
| Message Format | JSON or SOAP | JSON only |
Who Uses OCPP?
- CPOs (Charge Point Operators): Companies like ChargePoint, EVgo, and Fastned that operate charging networks
- eMSPs (e-Mobility Service Providers): Companies that provide charging access to EV drivers
- CSMS Vendors: Software companies building charging management platforms
- Charger Manufacturers: ABB, EVBox, Wallbox, Alfen, Schneider Electric
- Energy Companies: Utilities integrating EV charging with grid management
How to Test OCPP
Testing OCPP implementations requires validating hundreds of message flows, error scenarios, and edge cases. Traditional testing with physical chargers is slow and expensive.
OCPPLab provides a cloud-based OCPP simulator that lets you:
- Deploy 1000+ virtual charge points in minutes
- Test both OCPP 1.6 and 2.0.1 protocols
- Simulate real charger behaviors from 100+ device models
- Automate QA workflows and regression testing
- Validate smart charging, firmware updates, and error recovery
Teams using OCPPLab cut testing costs by 60-90% and reduce QA cycles from months to weeks.
Frequently Asked Questions
Is OCPP free to use?
Yes. OCPP is an open protocol maintained by the Open Charge Alliance. There are no licensing fees to implement it.
What is the difference between OCPP and OCPI?
OCPP handles communication between a charger and its management system (CSMS). OCPI (Open Charge Point Interface) handles communication between different charging networks for roaming — allowing an EV driver to use chargers from any network with a single account.
Do all EV chargers support OCPP?
Most commercial EV chargers support OCPP 1.6 at minimum. Tesla Superchargers historically used a proprietary protocol but are increasingly adopting OCPP for third-party access.
What is a CSMS?
A CSMS (Charging Station Management System) is the backend software that manages a network of EV chargers. It handles authorization, billing, monitoring, and remote operations via OCPP. Also called CPMS (Charge Point Management System).
