OCPI protocol explained: The backbone of EV charging interoperability

8 min read

Sep 29, 2025 10:00:01 AM

If there is one thing the EV charging industry needs, it is simplicity offered to EV drivers. The number of Charge Point Operators and E-mobility Service Providers out there is vast, and they don’t always work together. This creates friction for EV drivers, who cannot charge everywhere they need to. But to succeed with e-mobility, we need charging to be as simple as refuelling a petrol car. That’s why roaming protocols exist and why they’re so crucial.

So, how about the OCPI protocol? What is it, how does it work and most importantly, why does it matter? In this blog, we’ll talk OCPI from the ground up.

What is OCPI

The Open Charge Point Interface (OCPI) is an open protocol that allows communication between Charge Point Operators (CPOs) who operate charging stations and E-mobility Service Providers (EMSPs) who manage a network of EV drivers.

So why is this important? The adoption of electric vehicles is continuously growing, and charging should be as simple as fuelling a petrol car. Simply said, charging shouldn’t become a hindrance to further EV adoption. By adopting one widely used roaming protocol such as OCPI as the de facto standard of the industry, CPOs and EMSPs can easily connect and let EV drivers charge regardless of which charging network the belong to, as long as there’s a contract in place between the CPO and EMSP.

The OCPI protocol’s first development started in 2014, and its first version, OCPI 2.0, was released in 2015. Since 2020, the EVRoaming Foundation has managed and maintained the protocol and ensured its free availability.

What does OCPI enable

OCPI facilitates communication between the CPO and EMSP and lets them exchange data directly. This makes charging across different networks possible and helps bring convenience to charging.

Here are the functionalities OCPI provides for its 2.2.1 and 2.3.0 versions:

1. Roaming via hub

In OCPI 2.2.1, the Hub feature makes it possible for CPOs and EMSPs to connect like a central hub instead of each building dozens of separate links. This makes roaming easier, because one connection can open access to many partners at once.

2. Roaming peer-to-peer

Peer-to-peer roaming happens when CPO and EMSP build a direct connection, and each one’s OCPI endpoints enable them to communicate directly. Access to data is managed through bilateral contracts and the exchange of access keys (tokens).

3. Roaming with mixed roles

The mixed model combines both hub and peer-to-peer roaming. This approach is often chosen by large networks looking for optimal levels of control and reach. It also benefits EV drivers the most.

4. Manages authorisation

OCPI authorises charging sessions by identifying a driver’s RFID, app ID or Plug&Charge credential with their EMSP.

5. Shares charging station data

OCPI sends detailed charging station information, such as location, availability, connector types, and payment method, so EMSP can display this information in the app in real time.

6. Transfers tariff information

All tariff information is being transmitted. Tariffs can be static or dynamic, with clearly defined per-kWh, per-minute, or session-based models.

7. Handles session and CDR data

OCPI logs and transfers all session data, such as start and end times, kWh delivered or cost, and CDR data, which is crucial for billing.

8. Supports remote management

OCPI also allows EMSPs to start and stop charging sessions remotely via the mobile app, which is convenient for EV drivers.

9. Transfers CDR data for billing

While the OCPI protocol is not responsible for billing and invoicing, it does transfer Charge Detail Records (CDR), that are crucial for billing, between CPOs and EMSPs.

10. Supports smart charging

OCPI enables EMSPs to control when and how charging happens by setting constraints, i.e. setting maximum power or scheduling sessions.

11. Allows reservations

OCPI allows EMSPs to make and modify charger reservations, guaranteeing EV drivers will charge when they need to. This is particularly important for heavy-duty fleets that need to implement charging into their resting or unloading times.

12. Enables platform monitoring

OCPI parties can monitor the health and functionality of the OCPI connections to catch any errors before customers notice.

What OCPI doesn't do

While the list of what OCPI does is long, there are a few things OCPI doesn’t do. For one, it doesn’t communicate with hardware; that’s on the OCPP protocol. Sounds familiar? We have a specific blog all about OCPP, and we’ll also discuss the difference between the two later in this blog post.

Neither does OCPI process payments. It gives the EMSPs the data they need to bill the EV driver, but it doesn’t run any transactions.

Overall, OCPI facilitates communication between the two main players, CPO and EMSP. We have OCPP for communication between the charger and the back-end.

➡️ Learn about roaming at Virta!

Benefits for CPOs & EMSPs

OCPI was developed to facilitate the integration of Charge Point Operators with E-mobility Service Providers and vice versa. CPOs and EMSPs can enter into scalable roaming partnerships and provide simple charging experiences to consumers.

Increased utilisation:

By expanding to roaming customers, CPOs increase their revenue and build a business case for the future.

Attracting new customers:

When roaming is enabled, charging stations can be found and accessed by customers of other charging networks.

No reliance on specific manufacturers:

CPOs can install any OCPI-compliant charger without entering into specific agreements with individual manufacturers.

Strengthening customer loyalty:

EMSP’s customers won’t have to swap operators when they travel out of their own charging network, meaning they stay loyal to their service.

Offering broader access:

OCPI enables EMSPs to offer their EV driving customers the ability to charge at a larger number of chargers thanks to roaming contracts with various CPOs, enhancing their overall experience.

Benefits for EV drivers

To quote the EVRoaming Foundation,

“The ultimate goal is to allow any EV driver to charge at any charging station in the EU: simplify, standardise and harmonise.”

OCPI gives EV drivers more charging options, a better user experience and unified billing no matter where they charge.

Convenience:

Thanks to OCPI, EV drivers can access real-time charger location and status data and start charging at any of them.

Openness:

The EV driver does not need to create multiple customer accounts. A single account will enable them to charge at chargers from a variety of providers.

Easy payments:

EV drivers can easily pay through a single app or RFID tag.

Transparency:

The protocol provides EV drivers with up-to-date, transparent information on charging prices and the time it takes to charge up beforehand.

The evolution of OCPI

The first official release of OCPI, version 2.0, was published in 2015. Its core mission was to enable peer-to-peer roaming between CPOs and EMSPs without a central clearinghouse. From its first version, OCPI was meant to encourage EV adoption and avoid provider lock-in.

Version 2.1.1

This version is widely adopted, but limited in its optional features. New modules focused on enhancing Location, Sessions, and Tariff modules, enabling broader adoption and stability. The 2.1.1 version created a foundation for large-scale interoperability.

Version 2.2

In 2019, version 2.2 came to life and brought significant updates. Some key improvements included remote start and stop, enhanced tariff structures, improved CDR handling, and, probably the most important, support of roaming through hubs such as Hubject or Gireve.

Version 2.2.1

This version improved on the previous one, addressing identified issues and solving bugs. This improved version helped smoothen interoperability even more.

Version 2.3

In February 2025, the EVRoaming Foundation released the protocol’s latest version, 2.3. This was mainly an answer to the EU’s AFIR (Alternative Fuels Infrastructure Regulation). Version 2.3 complies with National Access Point regulations (part of AFIR) and includes optional Booking and Payment Terminal modules.

The future: OCPI 3.0

The OCPI protocol has now become the de facto standard for roaming in Europe and is quickly gaining traction in other continents. That’s why it needs continuous improvement.

A new protocol version, 3.0, is soon to be released, and it’s expected to include some exciting new features and functionalities. Here is a glimpse at some of them.

Plug&Charge and Autocharge support

This is probably the most awaited update as these authentication methods become prominent in the EV charging sphere. Plug&Charge and Autocharge automatically authenticate the vehicle only by plugging in. The EV driver doesn’t have to use any RFIDs or mobile apps; they simply plug in.

Direct messaging available

With OCPI 3.0, EMSPs can communicate pricing changes or charging issues directly via the charger screen. Something that wasn’t possible with the previous OCPI versions. This feature will improve transparency and user satisfaction.

Dynamic pricing, ad-hoc tariffs and crypto

The new OCPI version plans to support ad-hoc tariffs at payment terminals and allow EMSPs to accept multiple currencies, including cryptocurrency and display them in real time.

Grid integration

As the conversion of electric vehicle charging and energy systems becomes more important, OCPI 3.0 takes this development into account by enabling the sharing of meter values, load, and AC frequency measurements with Distribution System Operators (DSOs). This makes grid balancing smarter and helps avoid local grid congestion.

Data privacy and GDPR tools

Some OCPI 3.0 features are designed to support GDPR compliance, streamline contract management, and facilitate the transition of drivers to a new EMSP.

How OCPI supports AFIR compliance

With the EU’s Alternative Fuels Infrastructure Regulation (AFIR) coming into effect in April 2024, charging networks face stricter requirements around openness, transparency, and accessibility. OCPI has become the technical backbone to help CPOs and EMSPs comply.

Here’s how OCPI 2.3 addresses key AFIR obligations:

National Access Point (NAP) integration

OCPI 2.3 includes modules that share location, availability, and tariff information with each country’s NAP, ensuring that charging data is easily discoverable for EV drivers and regulators.

Tariff transparency

AFIR requires that EV drivers see transparent and comparable prices before starting a session. With OCPI, tariffs can be shared in real time and expressed in per-kWh, per-minute, or session-based formats.

Ad-hoc payments

AFIR mandates that all publicly accessible chargers support ad-hoc charging. OCPI 2.3 enables the exchange of data needed for EMSPs to support card or QR code-based payments at the charger.

Roaming enablement

AFIR’s emphasis on cross-border accessibility aligns perfectly with OCPI’s roaming design. By adopting OCPI, CPOs can meet regulatory and market expectations for a seamless driver experience.

Difference between OCPI and OCPP

The EV industry is a jungle of acronyms, and it’s easy to get lost in the meaning behind them all, especially when they’re so similar and enable similar things.

Take OCPI and OCPP, for example. Both are EV charging protocols that have something to do with interoperability. So, what is the difference between the two, and what are the things each protocol is for? Let’s dive into it.

As we established, OCPI is a protocol that enables communication flow between Charge Point Operators and E-mobility Service Providers.

OCPP, or Open Charge Point Protocol, is the global standard for communication between the hardware (EV charging station) and the software (Charge Point Management System (CPMS)).

OCPI inherently enables roaming in EV charging, i.e., EV drivers can charge at other charging providers than their own without any hurdles. OCPP enables charging network providers to integrate various hardware and software platforms as long as they are both OCPP compliant.

OCPI at Virta

Virta enables OCPI (version 2.2.1) to support seamless peer-to-peer connections between charging networks, creating a solid foundation for commercial agreements without the burden of high costs. Since OCPI is free to implement, two parties can connect directly without intermediary fees, making collaboration more efficient and scalable.

By adopting OCPI, Virta gives partners greater flexibility in price setting, data and network management, while also unlocking higher levels of automation across operations. This not only streamlines processes but also fosters a more open, cost-effective, and future-proof charging ecosystem.

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