Subscribe & get the latest news in your email
blue x
Charging Technology

What is Open Charge Point Interface (OCPI) for EV Charging?


March 24, 2023

The Open Charge Point Interface (OCPI) protocol is an open standard roaming protocol linking Mobility Services providers (MSP), Energy Service Providers (ESP), Navigation Service Providers (NSP), and other stakeholders with Charge Point Operators (CPO). It simplifies roaming between charging networks, letting EV operators use multiple stations without needing several accounts. This helps them find the best charging options.

OCPI standardizes communication between charging networks and shares information, ensuring everyone has the same data. This streamlines fleet management and billing processes. It also supports token exchange, location and status updates, and billing and payment processing.

Open charge point interface is important because it simplifies EV operators' access to various charging networks and ensures equal access to data. This makes managing fleets more efficient and cost-effective, saving time and money in the long run. 

On a global level, OCPI is being endorsed or adopted by governments, local and national initiatives, and companies including:

  • United States: The Corporate Electric Vehicle Alliance is pressing the US government to adopt OCPI and OCPP as standard changing protocols. 
  • United Kingdom: In 2022, the UK government Secretary for State for Transport proposed that OCPI should be adopted as a standard protocol to enable reliable and accessible EV charging.
  • European Union: evRoaming4EU is an international project that involves organizations from Austria, Denmark, Germany, and the Netherlands. The primary goal of this collaboration is to enhance roaming services for electric vehicle (EV) drivers and improve transparency by utilizing the Open Charge Point Interface (OCPI) protocol.

In this article, we will explain what OCPI and how it works in more detail, and outline its importance for EV fleets and charging point operators.

What Is OCPI?

OCPI, or Open Charge Point Interface, is an open communication protocol specifically designed for electric vehicle (EV) charging. Its purpose is to make it easier for EV drivers to find and use charging stations by facilitating communication between charging stations and multiple service providers.

OCPI is a useful standard in the EV charging industry because it promotes open communication and interoperability between charging stations and service providers. This means that EV drivers can find and use charging stations more easily and quickly.

How Does OCPI Work?

OCPI works by providing a standardized set of rules and guidelines that allow different EV charging software systems to communicate with each other using APIs. APIs are protocols, routines, and tools that standardize the way different software applications interact with each other.

OCPI allows for the free exchange of data, including locations, tokens, tariffs, and sessions, between the parties. OCPI provides fault-tolerant mechanisms for communication, allowing EV drivers to have real-time knowledge of available and unavailable charging points. The protocol also allows for direct connections between parties and can connect a large number of parties through one or more OCPI hubs.

EV charging software systems can use OCPI to communicate seamlessly, regardless of the type or brand of charging station or service provider. This ensures that EV drivers can use different charging stations from various providers and still have a consistent and convenient experience. 

In other words, OCPI makes it possible for different charging stations and service providers to "speak the same language," enabling a more user-friendly and convenient EV charging experience for drivers.

An Example Flow of OCPI in Practice:

To understand how OCPI works in practice, let's consider a simplified example flow:

  1. The driver initiates a charging session on a charge point hardware.
  2. The charging point sends status information (e.g., "charging") to the charging management system (CMS).
  3. The CMS confirms the status and informs the payment system through OCPI.
  4. The payment system authorizes the payment, and the charging session continues until completion.

It's important to note that the flow of OCPI can vary depending on the use cases, but the general process remains the same.

What Data is Exchanged with OCPI?

OCPI facilitates communication between different software systems by exchanging data and tokens related to EV charging. Some of the data that is exchanged through OCPI includes:

  • Address and location information of charge points (including geo-location)
  • Electric information of charge point hardware (current type, voltage, etc.)
  • Charge point's status information (e.g., if the charger is in use or available)
  • Credential information to authenticate the two backend software systems (similar to passwords or tokens)
  • Remote command to start and stop a charging session
  • Historical charging session data (e.g., Charging Detail Records (CDR))
  • Tariff information (costs per kWh, costs depending on the time of the day)

Advantages of OCPI in EV Charging

There are several key reasons why the Open Charge Point Interface (OCPI) is important in the world of electric vehicle (EV) charging.

  • Payment Processing: Many charging management systems (CMS) aim to improve charger uptime and energy management. However, payment systems can differ between states and countries, making it difficult to ensure consistent payment processing and interoperability between different networks. OCPI solves this issue by providing a common language that allows CMS to connect seamlessly with different payment systems and service providers. This ensures that everyone uses the same data format, promoting open communication and interoperability between charging systems
  • Easy-to-implement: Another significant advantage of OCPI is that it is based on APIs, which are widely used and well-known in the software industry. This means that engineers can work with OCPI easily without requiring any special education or training. This helps to reduce the barriers to entry for new players in the EV charging industry, promoting competition and innovation and helping to drive down costs for EV drivers.
  • Interoperability: By providing a common language for different charging networks and payment systems, OCPI promotes open communication and interoperability. This helps to simplify the charging process for drivers and promote the development of more extensive and efficient charging networks.
  • International Standards: OCPI is an international standard that is recognized by governments and industry organizations around the world. This means that it provides a common framework for EV charging systems across different regions and promotes consistency and interoperability.
  • Scalability: OCPI is designed to be scalable and flexible, allowing it to accommodate the growth and evolution of the EV charging industry. This means that it can adapt to new technologies, business models, and market demands, ensuring that it remains relevant and effective in the years to come.
  • Cross-Network Roaming: OCPI facilitates cross-network roaming, allowing EV drivers to access charging services from different networks and service providers using a single account. This makes the charging process more convenient and streamlined for drivers, promoting the widespread adoption of EVs.

OCPI vs OCPP: What Is The Difference?

OCPP and OCPI are two important standards in the world of electric vehicle (EV) charging, but they serve different purposes. Comparing OCPI vs OCPP:

  • OCPP (Open Charge Point Protocol) is a standard for communication between the charging point and the charging management system (CMS). It allows the CMS to control and monitor the charging process, access data on energy usage and charging session details, and receive error codes and other relevant information from the charging point. OCPP uses a WebSocket for bidirectional communication.
  • OCPI (Open Charge Point Interface) is a standard for communication between the CMS and other software systems, such as payment systems or roaming platforms. OCPI does not communicate with the charging point directly but enables the CMS to exchange data with other software systems using APIs.

Despite their differences, OCPP and OCPI share some similarities. They both deal with similar types of data, including charge point status, energy usage, charging session details, and error codes. However, OCPI goes beyond EV charging point information and includes data on energy tariffs, parking lot information, and other relevant details helping facilitate roaming between charging networks, whereas OCPP provides network managers the flexibility to make hardware and software choices from providers of their choosing.

OCPI vs OCPP Comparison Chart

Data exchanged Charge point status, energy usage, charging session details, and error codes Charge point status, energy usage, charging session details, error codes, energy tariffs, parking lot information, and other relevant details
Goal Allow network managers to choose their hardware and software from different providers Enable roaming between different EV charging networks
Use cases Primarily used by large EV charging networks Primarily used by small and medium-sized EV charging networks, as well as by individual charging stations

To learn how smart charging and OCPP work together to optimize your charging operations, read our report, "What Is OCPP and How To Use It For Smart Charging."


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.

Related Posts
See All Posts

Learn how fleet operators use Ampcontrol

Ampcontrol is a cloud-based software that seamlessly connects to charging networks, vehicles, fleet systems, and other software systems. No hardware needed, just a one-time integration.