Feb 25, 2024

What constitutes the Open Charge Point Interface (OCPI) for Electric Vehicle (EV) Charging?

Open Charge Point Interface (OCPI) fosters seamless communication and interoperability in Electric Vehicle (EV) Charging, providing a universal language for diverse stakeholders. Standardizing protocols, OCPI enhances connectivity, enabling transparent sharing of vital information and contributing to a more efficient and user-friendly EV charging experience.

What constitutes the Open Charge Point Interface (OCPI) for Electric Vehicle (EV) Charging?

The Open Charge Point Interface (OCPI) protocol serves as a universal roaming standard, fostering connections between Mobility Service Providers (MSP), Energy Service Providers (ESP), Navigation Service Providers (NSP), and other stakeholders, linking them seamlessly with Charge Point Operators (CPO). This protocol is a game-changer for electric vehicle (EV) operators, simplifying their experience by facilitating roaming across diverse charging networks. Operators can now access multiple stations without the burden of managing several accounts, providing them with flexibility and the ability to choose the most optimal charging options available.

What sets OCPI apart is its role in standardizing communication across various charging networks, ensuring uniformity in data sharing. By promoting the exchange of information, OCPI streamlines fleet management and billing processes. The protocol supports vital functions such as token exchange, location and status updates, and billing and payment processing, creating a cohesive and efficient ecosystem for all stakeholders involved in EV charging.

In the grand scheme of electric vehicle infrastructure, the Open Charge Point Interface holds significant importance. Its ability to simplify access to diverse charging networks ensures that EV operators have equal access to critical data. This not only enhances the efficiency of fleet management but also proves to be cost-effective in the long run. By providing streamlined access to charging options, OCPI contributes to time and cost savings, making it an indispensable component for the sustainable growth of the electric vehicle charging network.

OCPI has gained global recognition and adoption, receiving endorsements from governments, local and national initiatives, as well as various companies:

United States: The Corporate Electric Vehicle Alliance is actively advocating for the adoption of OCPI and OCPP as standard charging protocols by the US government.

United Kingdom: In 2022, the UK government's Secretary for State for Transport suggested the adoption of OCPI as a standard protocol, aiming to enhance the reliability and accessibility of electric vehicle (EV) charging.

European Union: The evRoaming4EU initiative is an international project involving organizations from Austria, Denmark, Germany, and the Netherlands. The primary objective is to collaborate on enhancing roaming services for EV drivers and fostering transparency through the implementation of the Open Charge Point Interface (OCPI) protocol.

In the following sections, we will delve into a more detailed explanation of what OCPI is, how it functions, and its paramount importance for EV fleets and charging point operators.

What Is OCPI?

OCPI, or Open Charge Point Interface, stands as an open communication protocol crafted explicitly for electric vehicle (EV) charging. The core objective of OCPI is to simplify the experience for EV drivers in locating and utilizing charging stations by establishing seamless communication channels between these stations and various service providers.

Within the EV charging industry, OCPI serves as a valuable standard by fostering open communication and interoperability between charging stations and service providers. This results in a more streamlined process for EV drivers to effortlessly discover and utilize charging stations.

How Does OCPI Work?

OCPI operates by establishing a standardized framework of rules and guidelines that enable diverse EV charging software systems to communicate with each other through Application Programming Interfaces (APIs). APIs serve as protocols, routines, and tools that standardize the interaction between different software applications.

This standardization allows for the seamless exchange of data, encompassing crucial information like locations, tokens, tariffs, and sessions among involved parties. OCPI incorporates fault-tolerant communication mechanisms, providing EV drivers with real-time insights into the availability status of charging points. Moreover, the protocol supports direct connections between parties and can link numerous entities through one or more OCPI hubs.

Regardless of the charging station or service provider's type or brand, EV charging software systems can utilize OCPI for seamless communication. This ensures that EV drivers experience consistency and convenience when using various charging stations from different providers.

An Example Flow of OCPI in Practice:

To illustrate how OCPI operates in real-world scenarios, consider the following simplified example flow:

  1. Driver Initiation: The driver commences a charging session on a charge point hardware.
  2. Status Communication: The charging point relays status information (e.g., "charging") to the Charging Management System (CMS).
  3. Confirmation through OCPI: The CMS verifies the status and communicates it to the payment system using OCPI.
  4. Payment Authorization: The payment system authorizes the payment, allowing the charging session to continue until completion.

While the specifics of the OCPI flow may vary based on use cases, the fundamental process remains consistent.

What Information is Shared via OCPI?

OCPI facilitates seamless communication between diverse software systems by exchanging essential data and tokens related to electric vehicle (EV) charging. Here are some of the key pieces of information exchanged through OCPI:

  1. Location Details:
  2. Address and geographical coordinates of charge points.
  3. Charge Point Hardware Specifications:
  4. Electric information regarding charge point hardware, such as current type and voltage.
  5. Status Updates:
  6. Real-time status information about charge points, indicating whether a charger is in use or available.
  7. Credential Data:
  8. Credential information essential for authenticating the two backend software systems, functioning akin to passwords or tokens.
  9. Remote Commands:
  10. Commands to initiate or terminate a charging session remotely.
  11. Charging Session History:
  12. Historical data related to charging sessions, often encapsulated in Charging Detail Records (CDRs).
  13. Tariff Details:
  14. Information regarding tariffs, encompassing costs per kilowatt-hour (kWh) and time-dependent charging costs.

By facilitating the exchange of this comprehensive data, OCPI ensures a standardized and interoperable framework for EV charging systems.

Benefits of OCPI in Electric Vehicle Charging

The Open Charge Point Interface (OCPI) holds several pivotal advantages within the realm of electric vehicle (EV) charging, contributing to the enhancement of charging systems on a global scale.

  1. Streamlined Payment Processing:
  2. OCPI serves as a universal language that fosters seamless connectivity between Charging Management Systems (CMS) and diverse payment systems. This standardization ensures consistent payment processing, overcoming the challenges posed by varying payment methods across states and countries. It promotes open communication, fostering interoperability among different charging networks.
  3. User-Friendly Implementation:
  4. A notable strength of OCPI lies in its foundation on Application Programming Interfaces (APIs), widely recognized and utilized in the software industry. This inherent familiarity allows engineers to work effortlessly with OCPI, eliminating the need for specialized training. This accessibility reduces barriers to entry for new players in the EV charging sector, stimulating healthy competition, fostering innovation, and ultimately benefitting EV drivers by driving down costs.
  5. Enhanced Interoperability:
  6. OCPI establishes a common language for diverse charging networks and payment systems, fostering open communication and interoperability. This simplifies the charging experience for drivers and supports the creation of more extensive and efficient charging networks. The standardized framework facilitates collaboration, ensuring compatibility across different platforms.
  7. Global Recognition as an International Standard:
  8. Acknowledged by governments and industry organizations worldwide, OCPI stands as an international standard. This recognition provides a unified framework for EV charging systems across regions, emphasizing consistency and interoperability. The adoption of OCPI contributes to the global standardization of EV charging practices.
  9. Scalability and Adaptability:
  10. OCPI is crafted to be scalable and adaptable, accommodating the dynamic growth and evolution of the EV charging industry. Its flexibility allows seamless integration with new technologies, diverse business models, and changing market demands. This ensures OCPI's continued relevance and effectiveness in the evolving landscape of EV charging.
  11. Cross-Network Roaming Facilitation:
  12. Enabling cross-network roaming, OCPI empowers EV drivers to access charging services from various networks and service providers using a single account. This promotes a more convenient and streamlined charging process, actively contributing to the widespread adoption of electric vehicles.

OCPP vs OCPI: Unveiling the Distinctions

In the realm of electric vehicle (EV) charging, OCPP (Open Charge Point Protocol) and OCPI (Open Charge Point Interface) stand as crucial standards, each serving distinct purposes. A comparative exploration of OCPI vs OCPP reveals their unique roles:

OCPP (Open Charge Point Protocol):

  • OCPP functions as a communication standard between the charging point and the Charging Management System (CMS). This standard empowers the CMS to govern and oversee the charging process, accessing essential data on energy consumption, charging session particulars, and receiving pertinent information such as error codes from the charging point. Leveraging WebSocket, OCPP ensures bidirectional communication for seamless interaction.

OCPI (Open Charge Point Interface):

  • In contrast, OCPI acts as a communication standard between the CMS and other software systems, such as payment platforms or roaming solutions. Unlike OCPP, OCPI doesn't engage in direct communication with the charging point. Instead, it enables the CMS to exchange data with diverse software systems through Application Programming Interfaces (APIs).

While OCPP and OCPI exhibit disparities, they also share commonalities. Both standards handle analogous types of data, encompassing charge point status, energy consumption metrics, charging session specifics, and error codes. However, OCPI extends its scope beyond EV charging point information. It incorporates additional data related to energy tariffs, parking facility details, and other pertinent information, facilitating seamless roaming across charging networks. On the other hand, OCPP provides network managers the flexibility to choose hardware and software from a variety of providers, offering a versatile approach to network management.

OCPI vs OCPP Comparison Chart


The Open Charge Point Interface (OCPI) protocol offers several benefits, including simplifying the charging process for drivers, promoting interoperability between different charging networks and payment systems, and reducing barriers to entry for new players in the EV charging industry.

OCPI provides a common language for different charging networks and payment systems, streamlining fleet management and billing processes and saving time and money in the long run. It is an international standard recognized worldwide, promoting consistency and interoperability.

Charging point operators can use both OCPI and OCPP to develop more extensive and efficient charging networks, ultimately driving the widespread adoption of electric vehicles.