The Difference Between OCPI and OCPP
Technical Information
The Difference Between OCPI and OCPP
What is the Difference Between OCPI and OCPP?
When researching electric vehicle (EV) charging infrastructure, you will definitely encounter the terms OCPP and OCPI. Both play a critical role in electric vehicle charging systems, but they are used at different layers and for different purposes. In this article, we address the differences between OCPP and OCPI in a clear and understandable way.
What is OCPP?
OCPP (Open Charge Point Protocol) is an open-source protocol used to establish communication between charging stations (hardware) and the central software systems (backend – CPMS) that manage them.
What does OCPP do?
Remotely manages charging stations
Provides data exchange between software and hardware
Supports operations like starting/stopping charging, error reporting, software updates
Transfers charging session data to the central system
? In short: OCPP enables the charging device's brain to communicate with the cloud system.
What is OCPI?
OCPI (Open Charge Point Interface) is a B2B-focused protocol that enables different charge point operators (CPO) and e-mobility service providers (e-MSP) to share data with each other.
What does OCPI do?
Provides roaming (inter-network switching) between different companies
Shares availability and pricing information of charging stations
Manages user identity, payment and billing processes
Transfers charging session data between different systems
? In short: OCPI enables charging network companies to integrate with each other.
How Do They Work in Real Life?
Thanks to OCPP, a charging device can be remotely started, updated, or error conditions can be monitored through software.
Thanks to OCPI, a user can charge at another company's station and make payment through their own application.
? Example Scenario:
A driver who is a customer of company X charges their vehicle at company Y's charging station.
The initiation, monitoring and data transfer of this session is provided by OCPP.
Authentication, price sharing and invoice transfer between companies X and Y are carried out via OCPI.
Both OCPP and OCPI are indispensable parts of electric vehicle charging infrastructure; however, they work at different layers:
OCPP → Manages charging devices
OCPI → Connects charging networks to each other
These two protocols work together to provide both infrastructure-side control and user-side accessibility. If you are planning to establish or expand your own charging network, understanding and supporting both protocols well will make your job easier in the long run.
Key Differences
Communication type
OCPP: Hardware ↔ Software
OCPI: Company ↔ Company (software ↔ software)
Parties covered
OCPP: Charging device ↔ Management system
OCPI: CPO ↔ e-MSP / other CPOs
Purpose of use
OCPP: Control and management of charging devices
OCPI: Data sharing between charging networks
Protocol structure
OCPP: WebSocket + JSON
OCPI: REST API + JSON
Connection direction
OCPP: Real-time, continuous connection
OCPI: Request-based, data exchange as needed
Who uses it?
OCPP: Hardware manufacturers, software developers
OCPI: CPOs, e-MSPs, platform providers
Versions
OCPP: Most common: OCPP 1.6 / 2.0.1
OCPI: Most common: OCPI 2.2.1
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