E-MobilityOpen StandardsOICPOCPI

OICP and OCPI protocols - open standards for CPOs and eMSPs


Piotr Majcher



OICP and OCIP - header picture


The initial stages of technologies lead to various types of solutions addressing the same problem. Each company develops a different approach. At the beginning of the XXth century, when commercial electricity had come to the mainstream, multiple energy producers offered power supply with miscellaneous frequencies and voltages. As time passed, governments began to impose certain standards on suppliers. This standard-setting led to the joint effort to create the first power grid.

From the first power plant to the moment when all energy providers linked to the same network, decades passed. This was only possible because they took a mutual direction.

Nowadays we deal with other issues. E-mobility takes charge - literally and figuratively. With global warming, exhaustion of solid fuel resources, and lifestyle changes, companies face the challenge of how to provide accessible new charging forms of green power.

E-mobility era

Now, as the e-mobility era is here, we are on the same page, like we were at the very beginning of the XXth century. We already have plenty of providers: eMobility Service Providers (eMSP) and Charge Point Operators (CPO) - two substantial sides of the e-Mobility world. One of the main challenges ahead of this market is to deliver the best user experience, at possible minimum resources use. As usual, user experience is a matter of well-designed apps, customer support, and simplicity itself. But there is an additional fact. End-users need to be able to charge cars at any charging station without being concerned about accessibility. The issue is - having the contract signed with the Charge Point Operators recharging point service. How to achieve this? Partners must take the same course, and this is where the standards start to play a major role. There are two possibilities: Open Charge Point Interfaces or Open Intercharge Protocols. What are the benefits?

Open Charge Point Interface

The main goal of the Open Charge Point Interface (OCPI) is to allow electric vehicle drivers to charge their cars at any station. OCPI defines a set of modules that cover most cases the driver may need. There are two technical modules that are used to establish connectivity between two platforms using OCPI: Credentials module and Versions module. Other modules are strongly related to real-life use cases. These would be:

  • Locations - module responsible for sharing information about the Charge Points, like address, geolocation, real-time data about the current status, electrical parameters.
  • Sessions & Commands - module allows the end-user to start the charging session and be informed about the current status of the charging session.

OCPI is an open standard, and what may be very important for the adopters - it’s very flexible. For instance, CPOs (Charge Point Operators) may implement only the Locations module (apart from two technical mandatory modules) when only sharing Point Of Interest data. With no necessary exposing the eRoaming functionality. But the ultimate goal for many CPOs is to allow end-users to charge their car. In that case, many more modules need to be implemented (Sessions, Commands, CDRs). Some others are optional, even for the eRoaming (Tokens, Tariffs), and that depends on the agreement between certain allies. It’s in terms of how financial flow and security is modeled.

The biggest advantage of having OCPI implemented is that it’s almost a one-time investment. The initial effort is significant, as it might be challenging to transfer internal models and processes to the OCPI. But once it’s done for a partner, it opens the company for quick and cost-effective integration with a lot of other associates.

Open Intercharge Protocol by Hubject

A bit different concept is proposed by the Berlin-based innovative company - Hubject. Hubject developed its own API (OICP) covering almost the same cases as OCPI. There is one extra. Hubject also acts as a hub. It connects CPOs and eMSPs. Once a company is connected to the Hubject platform, it becomes open for integration with any other comrade being already assigned. That’s a huge advantage because the integration is done once, with one platform, and of course it becomes profitable when it comes to an alliance with multiple partners.

Yet another advantage of the Open Intercharge Protocol is that it’s quite easy to implement. Like with most protocols, the main challenge is to synchronize our internal models with the standard one. What is comforting with OICP - there is not too much to implement. It depends on the level of integration we want to achieve, but it’s enough to implement about 5 HTTP calls to expose eRoaming through the Hubject platform.


Having in mind multiple historical examples, it may be difficult to be a part of a developed market without following widely adopted standards. Initially, it may need some additional effort. But when the standard is implemented, our platform becomes open for the whole market almost immediately. Without it, we would need to spend weeks or months doing the integration with each partner separately.