Arjun Harindranath
Published on
February 23, 2023
5 min read

2 minute explainer: What’s the difference between OCPP and OCPI?

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EV charging terminology can often be an alphabet soup with a number of acronyms and abbreviations along the way. In this brief article we look at how the Open Charge Point Protocol (OCPP) differs from the Open Charge Point Interface (OCPI). 

The Road to Roaming

The Open Charge Point Protocol (OCPP) governs how charging stations communicate with the centralized network server or the backend. This two-way communication system is crucial for Charge Point Operators (CPOs) to establish when charging starts and stops, register new users and enable payments via RFID cards or QR codes.

However, the excitement to form new EV charging networks also led to multiple networks protecting their market share by requiring their own branded cards to charge. The result was a poor user experience for EV drivers who would require signing up at multiple networks to stay charged.

You don’t worry about which socket can charge your phone or laptop. Why should EVs be any different?

Breaking down barriers

Having networks with barriers was creating a poor user experience for EV drivers. Breaking them down was the role of new players that were emerging in the EV charging market. These players were referred to as eMobility Service Providers (or eMSPs). 

While still new to the US market, eMobility Service Providers have been in play in Europe for a while now. In the interests of providing a more seamless experience for EV drivers, eMSPs break down the barriers between networks. 

The rules which they follow in breaking down these barriers is the Open Charge Point Interface (OCPI). 

In the case of OCPI, the communications are between the charge point operators and the mobility service providers. OCPP, on the other hand, is a protocol that governs the communication between CPOs and the charging stations themselves.


Let’s use an example to make things a little clearer. Let’s say Chargem is a Charge Point Operator with its own network of 5,000 charge points throughout California. On a daily basis they use their centralized server to communicate with their charge points. Chargem signs up new drivers and controls all charging sessions and payment transactions via this centralized server. These communications are all established via OCPP. 

On the other hand, MobilityYou–an eMobility Service Provider–is also working in a partnership with Chargem by ensuring that EV drivers who may not be in Chargem’s network, can also use their charge points. MobilityYou communicates with Chargem to help facilitate this and these communications all follow the rules within the OCPI.

The future of interoperability

We’ve only just scratched the surface of OCPI and its potential to bring down walls that had previously existed between charging networks. A fuller explanation of OCPI is described by the EV Roaming Foundation that developed the free and independent protocol.

In addition to our expertise in OCPP, eDRV is also committed to a future of electrification without barriers. This means that roaming isn’t just commonplace, it’s expected.

Interoperability of EV charging networks is key to ensuring that the EV charging ecosystem is for everyone to participate in. Find out more about how eDRV is empowering mobility service providers to break down barriers in the US.  

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