See the seventh lesson of our comprehensive eMobility training on OICP!

Having a chance to work with well-established startups from the e-mobility sector, Bartek gained invaluable knowledge on the industry requirements. On his path, he was given the opportunity to work on numerous EMSP applications and CPO platforms. Bartek is also our Head of Delivery.

Bartłomiej Łazarczyk

 is happy to introduce you to the Open Standards course led by our e-mobility expert - Bartlomiej. Throughout the following lessons, we will uncover the technicalities and functionalities of the OICP - a protocol developed by 

 - as well as business aspects for e-Mobility Service Providers and Charge Point Operators.

Such a knowledge-pack should serve everyone operating in the e-mobility industry as it unfolds the most crucial aspects of navigating through Open Standards utilization and many more!


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CPO eRoamingAuthorization + eRoamingReservation

CPO eRoamingEVSEdata + eRoamingEVSEstatus

CPO eRoamingDynamicPricing + eRoamingChargingNotifications 

Open InterCharge Protocol Training - Lesson 7

Now, we are going to look deeper into previously discussed services but from an EMP perspective. For most of the parts, it's the same as for CPO, but EMP also has some operations that are unique and specific only to them. Let's start.

Of course, the first operation in eRoaming Authorization Service is eRomingAuthorizedStart. Similar as for CPO, it is used for authorizing the charging process in the Hubject platform. Its implementation is mandatory for every online EMP partner. The data model and logic is the same as for CPO related operation, the only difference is that now EMP must be able to handle AuthorizedStart request and return eRoamingAuthorizationStart response.

The next operation is eRoamingAuthorizedStop - it is used for authorizing the stop of the charging process. Again, the data model and logic is the same as for CPO related operation. EMP must be able to process AuthorizedStop request and return eRoamingAuthorizationStop response.

eRoamingAuthorizedRemoteStart operation is very important for EMP. It allows EMP customers to directly start a charging session with, for example, a mobile application. Of course, implementation is mandatory by every EMP partner. Fortunately, the data model and logic is the same as for CPO operation. This time, EMP sends eRoaming authorized remote start request which must be processed by CPO and then CPO must return eRoaming Acknowledgement which is directly forwarded to EMP.

The opposite operation is eRoamingAuthorizedRemoteStop it allows EMP customers to directly stop a charging session with i.e. mobile application. Similar as for eRoamingAuthorizedRemoteStart, implementation is mandatory by every EMP partner. Also, data model and logic is the same as for CPO related service.

As we already know from the CPO authorization service, a CDR must be sent after the charging process has been finished. In order to be an online EMP, you must implement eRoamingChargeDetailRecord operation. EMP system must be able to handle charge detail record request and return eRoaming acknowledgement as a response.

But what happens when you would like to be an offline EMP? Or when Hubject tries to communicate with your EMP system but it fails and you cannot receive a CDR? In this case, eRoamingGetChargedDetailRecord operation might be useful. It allows EMP to pull CDRs data that was sent by CPO to the Hubject platform. EMP does not have to handle CDRs in real time, instead it can build some automated process on top of that operation. It's worth to mention, that EMP can pull CDRs in case real-time processing is not possible i.e. due to technical errors. eRoamingGetChargedDetailRecord request is simple. EMP must specify a date range, what can be done by providing from and to date values. EMP may also narrow down the result by specifying a list of session IDs. Also, it is possible to provide CDR forwarded which indicates whether the results should contain only those CDRs which were successfully forwarded to EMP or maybe not. response feRoamingGetChargedDetailRecord request is a list of eRoamingChargeDetailRecord. It's good to know that the data should be paginated.

If CPO offers eRoamingReservation service EMP may subscribe to it and offer its customers a possibility to reserve a charge point of given CPO. This can be done with eRoamingAuthorizedRemoteReservationStart operation. Information if chargepoint can be reserved is included in the value-added services field in EVSE data. Hubject must create a session for every reservation, because reservation may include some costs which are not strictly connected with the charging process itself. For example, it can be a fixed fee. The logic and data model are the same as for CPO-related service.

Second operation is already known: eRoamingAuthorizedRemoteReservationStop. It allows EMP customers to end existing reservation. After finishing a reservation, CPO must generate a CDR for a session that is connected to a given reservation. Again, data model and logic is the same as for CPO related service.

This service and eRoamingPushAuthenticationData operation is dedicated only for EMPs and its implementation is mandatory for every offline EMP partner. Hubject offers a possibility to push authentication data by EMPs to the daily platform, in order to optimize the full authentication process. For an offline EMP that's the only way for their customers to authenticate, therefore this operation is mandatory. For an online EMP you can use push authentication data to optimize the process, but you can have real-time authentication data processing available at the same time. Similar as in other services, update and delete is done with an action type field. Hubject will also keep history of all authentication data records in their platform.

In eRoamingPushAuthenticationData request, you must provide a provider ID together with a list of authentication data records. In each authentication data record you may specify multiple options for customer identification, for example it can be identification by RFID card or by QR code.

eRoaming Hubs explained

Get our comprehensive PDF packed with knowledge on eRoaming, hubs and protocols!

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

Certainly, roaming is something known to everyone at this point. However, what that has to do with eMobility?

Being a broad term for services allowing for connection outside of the usual network, roaming turns out to be an on-point solution for EV charging. With many players in the eMobility game (i.e. Charging Point Operators, eMobility Service Providers), some type of a connector is a must. Here’s exactly where eRoaming comes into play allowing for multi-dimensional connection between operators and EV drivers.

In short, eRoaming can be established via the use of hubs and protocols. A hub here can be an open platform which, after subscribing, can be used by many operators, who operate on common terms. This all happens in such a way that a certain charging pool introduced to a common hub can then be easily used by clients (EV drivers) of different providers. Such a solution allows electric vehicle users to charge their car across cities/countries with limited hussle.

In order to facilitate such a solution, the hubs developed their own open protocols, which are essentially responsible for the connection. They also define the functionalities of each eRoaming platform.

Amongst the existing hubs, we can differentiate three major ones. They all come with their own open standards and unify hundreds of CPOs and EMPs as well as millions of EV drivers.

The three biggest hubs and their protocols are:

(eMobility Inter-Operation Protocol - eMIP)

Apart from the proprietary protocols coming from hubs, it’s worth mentioning that there's also an independent one - 

Open Charge Point Interface Protocol (OCPI)

. It allows for eRoaming between the hubs as well as peer-to-peer connection.

To learn more about eRoaming, hubs & protocols, their importance and functionality as well as the future of eMobility - take a look at our exclusive paper covering all that needs to be covered on the topic!

Download our comprehensive PDF and learn about the pricing structures in e-mobility

Although it would seem rather straightforward, the pricing system within the EV charging environment extends further than just to the payments made by electric vehicles right after they charge their car.

Being such an interconnected network of mutual dependencies between numerous involved parties, e-mobility charging services require various levels of settlements.


It must be noted that it takes a few units to build up and manage a charging network. From 

, which manufacture the hardware side of required components (connectors, chargers, cables, etc), through 

, which are responsible for the backend management, all the way to 

, which determine the final user (here: EV driver) experience, there is a whole network of reliabilities.

Put simply and briefly, CPO’s are to establish billing connections with both EVSE and eMSP’s, in order to put the entire charging formation in place, while ensuring all parties receive transparent information and clear instructions.

To facilitate it, there are multiple types of pricings and contracts, some of which allow for complex, dynamic price models. Such undertaking is required so that eMSP’s can shape their end-users pricing often based on certain conditions, leaving the rates flexible.


Interoperability - the core of proper functioning

It should go without saying, that managing a pool of charging stations - oftentimes distributed across entire countries/regions - is not an easy task to handle and can only be achieved via advanced levels of interoperability and clear, unified procedures.

Open Standards are the chief example of how this can be achieved and maintained. Through the utilization of API’s like OICP the flow of information can be sustained in a transparent manner. This allows for a seamless communication and can facilitate the management of a vast majority of proceedings remotely, which comes in handy while developing a state-wide network, especially when there are numerous parties involved.


Knowing the behind-the-scenes nuances and arrangements, we prepared a comprehensive paper portraying the pricing structure within the e-mobility industry. Those who are willing to learn more about tariffs within charging services, should definitely find it useful.

Download our free paper and broaden your horizons with some great knowledge!

E-mobility tariffs. How is the pricing structured within the industry?

Open standards can be a game changer for both eMSP's and CPO's. Here is why.

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.

 - 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.

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?

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.

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 

. Without it, we would need to spend weeks or months doing the integration with each partner separately.

Open InterCharge Protocole Training. Lesson 7

12 APRIL 2022 • 7 MIN READ