Refresh the knowledge on OCPP and see what changes have been implemented over the last years!

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

 on OCPI. Given how widely read it was, we thought it’d be a good idea to continue the series on open protocols in the EV charging diligence.

Standing at the forefront of EV mass adoption, open standards and protocols are essentially responsible for the communication within the industry. They connect all involved parties (i.e. CPOs, EMPs, EVSE) altogether and allow for the data exchange, staying up-to-date and allowing for EV drivers to actually facilitate the charging sessions.

We have already covered quite a lot on the subject of open standards, for those interested, here’s the list of some entries so far:

EV roaming with open standards - OICP and eMIP

EV roaming with open standards - OCPI and OCHP


In this piece, all the focus goes into the Open Charge Point Protocol - OCPP.

OCPP has been developed by the Open Charge Alliance, a consortium of electric vehicle infrastructure providers, automakers, utilities, and other stakeholders. OCPP is a communication protocol used by charging stations and electric vehicle service providers. It enables two-way communication between the EVSE and CPOs, allowing for the monitoring and control of charging sessions.

OCPP is an open protocol, and anyone can develop applications that use it. Yet, it has not been officially deemed as standard, meaning that as much as OCA highly recommends using it, it’s not obligatory for EVSE manufacturers to produce hardware compliant with OCPP.

In terms of what it does, understanding of the OCPP placement in the entire ecosystem is crucial. As it has been stated earlier, OCPP is the syntax connecting the CSMS (Charging Station Management System used by CPOs to control their networks) with the actual hardware appliances (charging stations). Amongst operations covered by OCPP there are:

: enables identifying the EV driver and starting/finishing the charging event

: the charging event data is transferred to the backed system to define the chargers and bill the EV user accordingly

: CPOs can monitor the stations’ statuses (i.e. which are currently occupied, which have some issues detected)

Throughout the years, there have been a few versions of OCPP published. Two most recent ones are - OCPP 2.0 and 2.0.1. We’re gonna focus on these two, as they’re currently the most relevant.

In terms of the migration from the previous version (OCPP 1.6), we have covered that subject in this article. When it comes to OCPP 1.6, this version was enriched with multiple new features compared to its 1.5 predecessor (now mostly out of use). As we read in the documentation, to OCPP 1.6 there have been added:

A binding to JSON over WebSocket as a transport protocol is added, reducing data usage and enabling OCPP communication through NAT routers, see: OCPP JSON Specification

Extra statuses are added to the ChargePointStatus enumeration, giving the CPO and ultimately end-users more information about the current status of a Charge Point Structure of MeterValues.req is changed to eliminate use of XML Attributes, this is needed for support of JSON (no attribute support in JSON).

Extra values are added to the Measurand enumeration, giving Charge Point manufacturers the possibility to send new information to a Central System, such as the State of Charge of an EV

The TriggerMessage message is added, giving the Central System the possibility to request information from the Charge Point

A new Pending member is added to the RegistrationStatus enumeration used in BootNotification.conf

More and clearer configuration keys are added, making it clearer to the CPO how to configure the different business cases in a Charge Point

The messages and configuration keys are split into profiles, making it easier to implement OCPP gradually or only in part

Known ambiguities are removed (e.g. when to use UnlockConnector.req, how to respond to RemoteStart/Stop, Connector numbering)

(please note, this extract comes from the OCPI 1.6 documentation and can be downloaded in full from their website)

Now let’s focus on the two latest versions. OCPP 2.0 was first introduced in April 2018. Since then, some issues have been found. As it turned out, some of the problems couldn't have been solved by fixing textual nuances in the documentation and needed bigger changes, to the point where they weren’t backward compatible. This included i.e. messages improvements (like the length of the security message certificate which happened to be too short). This is when OCPP 2.0.1 was introduced and it's recommended by OCA to use this one only.

As the OCPP standard continues to evolve, it is important for charging station operators to stay up-to-date on the latest version of the OCPP protocol. Doing so will ensure that their charging stations are compatible with the latest CSMS software and able to take advantage of the newest OCPP features.

In terms of how OCPP 2.0 followed by 2.0.1 have changed compared to OCPP 1.6, there’s been some major changes. First and foremost an ISO 15118 support has been introduced. In return, this has opened up the possibilities such as the Plug and Charge functionality. In the newest version SOAP is no longer supported as it has been entirely replaced by JSON websockets. There have also been some major improvements in the security area. Amongst some slightly smaller changes,

device management & monitoring replaced formerly used Status Notifications. The transaction handling has been improved so that it could support bigger and more complex networks.

The official OCPP documentation consists of 7 parts:

JSON over WebSockets implementation guide

ISO 15118 - what is it?

Check our friendly reminder about OCPI and its newest version.

Staying up-to-date with the latest upgrades across different branches of eMobility can be quite a task at times. Significant ameliorations are coming in whether it’s the hardware or software. This is especially challenging for charge point operators and eMobility service providers as they get to deal with both sides at all times. The software maintenance should aim to keep up not only with in-house changes but also (equally importantly) with external protocols that are integrated. All this in order to examine if there are new opportunities upfront our business that can be supported by the newest version of the protocol we use. Upgrades are vital also due to the fact that some of the protocols simply won’t work on outdated versions, after a major update is introduced.

Here, we’d like to briefly walk through the changes and current version of OCPI.


It’s an independent standard allowing for eRoaming between the hubs as well as peer-to-peer connection. However, OCPI also supports communication in-between roaming hubs. This way, charge point operators (and mobility providers) could exchange data, even when they are connected to different roaming hubs and when they do not have a direct peer-to-peer connection. OCPI is developed and managed by EV Roaming Foundation, which naturally is responsible for updates introduction.

In terms of functionalities brought by OCPI regarding information exchange between interested parties, there are:

 - OCPI facilitates data exchange between eMSPs and CPOs via hubs, for this operation, the protocol offers a separate hub supporting module.

 - Both eMobility Service Providers and Charge Point Operators can correlate immediately via OCPI. Separate interfaces are designed for eMSPs and CPOs.

 - The token module in the OCPI architecture supplies Charge Point Operators with the knowledge of any token information of eMSP. There are two ways to execute authorization, which could be real-time or via a whitelist.

 - On the eMSP side, the OCPI offers to make and cancel a reservation.

 - OCPI supports the basis for invoicing - sending CDRs - Charge Detail Records.

 - The protocol supports the exchange of the key details related to energy tariffs. Complex tariff calculations depend on the time charged and energy. All this information is included in the tariff module.

 - This covers: IDs, CPOs, charge point site, host, charge point name, charge point location details (name, address, geocode, type, image, platform level, directions), nearby facilities, link to a website, time zone, opening times, current availability status, scheduled availability status, accessibility, tariffs, authorization modes, payment methods, terms and conditions, charge mode, connector type, maximum power, voltage, amperage, energy mix, remote start/stop, reservation, smart charging support, and the last update mark.

 - Stats: available, blocked, charging, inoperative, out of order, planned, removed, and reserved.

real-time & static) - Covers: sessions ID, start time, end time, energy consumed, CDR ID, authorization method, location, charge point ID, meter ID, currency, charging periods, total cost, sessions status, and last update. The same information can also be in real-time.

 - CDR IDs, time, duration, finish status, and more.

 (Eichrecht) support - OCPI maintains the exchange of signed meter data which can be used to conform to Eichrecht - German calibration law.

 - The start and stop of any charging session can be done remotely via the eMSP app.

 - Several charging profiles are supported by OCPI: the cheapest charging, the fastest charging, the most environmentally-friendly charging, or no particular choices. The preferences can be registered per session by the user. The CPO can accept or decline the option. Although the smart charging profile module does provide certain options, these cannot be ensured, since other factors influence the charging session.

More information about OCPI can be found 

As described by EV Roaming Foundation, OCPI:


Offers market participants in EV an attractive and scalable solution for (international) roaming between networks, avoiding the costs and innovation-limiting complexities involved with today’s non-automated solutions or with central roaming hubs. As such it helps to enable EV drivers to charge everywhere in a fully-informed way, helps the market to develop quickly and helps market players to execute their business models in the best way.

Release of OCPI 2.2 brought big updates compared to its 2.1.1 version. New features involve:

message routing headers (ensuring better communication via hubs) and hub client information (allowing connected parties to view each other’s connection status; i.e. CPOs can check which eMPS are currently online)

Support Platforms with multiple/different roles, additional roles 

(including: type of role, business details, party ID, country code)

(via ChargingProfiles module parties, i.e. eMPS can send charging profiles to EVSE)

(allowing EMP to send preference on behalf of EV driver)

In terms of the improvements, in OCPI 2.2 we can find ones regarding

Not very much different from its previous version, OICP 2.2.1 was released as an answer to some issues reported for 2.2 version. In all cases, these are minor inconveniences, which update shouldn't be a complicated task. At the same time, version 2.2.1 can fix some irritating small details.

The changes are detailed in a table below:

OCPI 2.2.1 updates as stated in documentation by EVRoaming Foundation

The full protocol documentation with elaborated explanation and features walk-through can be found on EVRoaming Foundation website 

OCPI 2.2.1 - what's new?

Two actively supported independent open standards for EV roaming.

In a search for interoperability, the e-mobility market players need to speak the same language. Demand for coherent infrastructure is dictated by rapid EV penetration. Several factors, such as local policies and incentives, contribute to an enthusiastic approval of electrically-powered vehicles. Hence, the focus has been transferred to the network and its ability to create open, accessible infrastructure. To match the pace - resonate with market expectations and work together to create an accessible, open environment - the new order needs EV roaming.

EV roaming is something users cannot see but witness, and whether knowingly or not, appreciate. Open standards create the road to consistent and complete e-roaming. With a large pool of contributors, up-to-date and secure solutions are available at hand to any participant in the rapidly growing e-mobility market. To understand the role of open standards in e-mobility here are explanations for widely approved models.

Note: In the e-mobility world there are four main open standards facilitating e-roaming. Two are developed and maintained by non-commercial hub operator and independent knowledge board - OCPI Open Charge Point Interface and OCHP - Open Clearing House Protocol & OCHPDirect. Two others were developed by commercial roaming hub operators. These are OICP Open InterCharge Protocol designed by Hubject and eMIP - eMobility Interoperation Protocol maintained by GIREVE.


Originally developed by eViolin, a Dutch association of Charging Station Operators and eMobility Service Providers, that pursues national roaming with international connection, using open standards. In cooperation with ElaadNL -  the knowledge and innovation center in the field of Smart Charging and the charging infrastructure in the Netherlands - major Dutch grid operators. Initially governed by the Nederlands Kennisplatform Laadinfrastructuur (NKL) - Netherlands Knowledge Platform for Public Charging Infrastructure - a partnership of business organizations, governmental figures, and research institutes. From May 2020 the OCPI is managed and maintained by the EVRoaming Foundation. Open Charge Point Interface offers p2p and any roaming hub integration business model.

OCPI is registration-free, openly available at no cost. Published under the Creative Commons Attribution-NoDerivatives 4.0 International Public License. Hence, the distribution is free when given proper credit. Although blocks the distribution of the modified versions of the protocol. The most recent version (v2.2) was released in October 2019. Open Charge Point Interface offers a modular set-up, a very convenient way of deployment - it is up to the individual decision which modules to include. It also covers a variant check, a significant factor for peer-to-peer mutuality as there is no fundamental actor applying updates or completing to support previous protocol versions.

Open Charge Point Interface is the only, so far, set on JSON/rest and is a real-time protocol. It maintains synchronous and asynchronous operations.

Open Charge Point Interface carries multiple explications for Eichrecht (German calibration law for electric vehicle charging), as recommended by the top European e-mobility providers - Has-to-be, Alfen, eBee, and Mennekes. In March 2021 EVRoaming Foundation announced the start of the first independent Roaming Agreement pool. The organization aims to support setting up trusted agreements between parties, for either p2p or via a (virtual) roaming Hub. The pool is available for all Full Contributors (The foundation distinguishes the following membership classification categories: Full Contributor, Associate Contributor, Sponsors, and Managing Contributors).

The protocol’s documentation describes market roles as follows:

The EV user connects to a charge point in can be provided information from the MSP

The e-mobility service provider (eMSP), grants EV services to EV users. eMSP connects to Charge Point Operator (CPO) to offer e-roaming services.

The CPO manages, maintains, and operates charge points (charge stations), on the technical and administrative side. CPO is open to connecting to MSPs to offer roaming services.

The e-mobility service provider ensures charge point location information.

The eMSP influences smart charging sessions depending on extra sources of information.

The purpose of a roaming hub is to facilitate information exchange between market players. In this division Open Charge Point Interface supports:

Roaming via hub - OCPI facilitates data exchange between eMSPs and CPOs via hubs, for this operation, the protocol offers a separate hub supporting module.

Roaming peer-to-peer (p2p) - Both eMobility Service Providers and Charge Point Operators can correlate immediately via OCPI. Separate interfaces are designed for eMSPs and CPOs.

Authorization - The token module in the OCPI architecture supplies Charge Point Operators with the knowledge of any token information of eMSP. There are two ways to execute authorization, which could be real-time or via a whitelist.

Reservation - On the eMSP side, the OCPI offers to make and cancel a reservation.

Billing - OCPI supports the basis for invoicing - sending CDRs - Charge Detail Records.

Tariff information - The protocol supports the exchange of the key details related to energy tariffs. Complex tariff calculations depend on the time charged and energy. All this information is included in the tariff module.

Static charge point information - This covers: IDs, CPOs, charge point site, host, charge point name, charge point location details (name, address, geocode, type, image, platform level, directions), nearby facilities, link to a website, time zone, opening times, current availability status, scheduled availability status, accessibility, tariffs, authorization modes, payment methods, terms and conditions, charge mode, connector type, maximum power, voltage, amperage, energy mix, remote start/stop, reservation, smart charging support, and the last update mark.

Real-time charge point information - Stats: available, blocked, charging, inoperative, out of order, planned, removed, and reserved.

Session information (real-time & static) - Covers: sessions ID, start time, end time, energy consumed, CDR ID, authorization method, location, charge point ID, meter ID, currency, charging periods, total cost, sessions status, and last update. The same information can also be in real-time.

CDR information - CDR IDs, time, duration, finish status, and more.

Callibration law (Eichrecht) support - OCPI maintains the exchange of signed meter data which can be used to conform to Eichrecht - German calibration law.

Remote start/stop - The start and stop of any charging session can be done remotely via the eMSP app.

Smart charging - Several charging profiles are supported by OCPI: the cheapest charging, the fastest charging, the most environmentally-friendly charging, or no particular choices. The preferences can be registered per session by the user. The CPO can accept or decline the option. Although the smart charging profile module does provide certain options, these cannot be ensured, since other factors influence the charging session.

OCPI’s ultimate goal is to allow any EV driver to charge at any charging station in the EU. In fact, the protocol is used intensively throughout Europe (Netherlands, Belgium, Luxembourg, UK, Germany, France, Spain, Italy, Denmark, Austria, Poland), but not limited. It also gains recognition, among others, in the USA, Canada, South Africa, and India. The protocol is gaining acceptance in ever-widening circles and the number of countries is steadily increasing.

OCHP - Open Clearing House Protocol and OCHPDirect

OCHP is the second protocol that offers a hub or p2p connection. Integration with hubs is done via OCHP, and the direct peer-to-peer connection is possible with OCHPDirect. The solution is maintained and expanded by Smartlab Innovationsgesellschaft GmbH.

and ElaadNL (ElaadNL also supports aforementioned OCPI), organizations established by German and Dutch entities. OCHP is used by the roaming hub e-clearing.net (e-clearing.net also offers connectivity via mentioned above OCPI) operated by Smartlab and owned by Smartlab and ElaadNL. As a not-for-profit platform, the main interest of e-clearing.net is to develop the e-mobility market. Both available current versions OCHP v1.4 and OCHPDirect v0.2.6 were released in August 2016 (In October 2020 OCHP introduced to members the newest update 1.5, but no further public information was provided, the valid version remains 1.4).

The OCHP documentation is free to download and does not demand registration. Thanks to the MIT license, the protocol allows for open distribution and alteration. The administration of the OCHP lies on the Smartlab/ElaadNL side, which has the remaining right to apply and execute edits to the protocol. Prior and complete implementation testing needs to be conducted before a participant gains access to the e-clearing.net roaming platform. To support a coherent development of the OCHP protocol each year developers collect user feedback.

The Open Clearing House Protocol is based on the SOAP (Simple Object Access Protocol) computer protocol. It largely relies on asynchronous communication (opposed to real-time communications, as for OCPI). For instance, e-clearing.net does not store transaction data. Instead of real-time authentication, OCHP forms lists of users who are allowed to authenticate. This approach allows avoiding a single point of failure (SPOF) - if the roaming hub breaks down, charging sessions remain active.

The OCHP protocol documentation describes the following market roles:

The EV user, that has a direct or indirect contract with an eMobility Service Provider, charges an EV at a charge point/charge station.

The eMSP grants access to charge points/charge stations to the EV owner. The eMSP provides the EV user access via an RFID card or certificates. The service is supported by CPOs. The CPO operates charge points and acts as a contract agent for the eMSP. Each charging session is settled between the eMSP and the CPO under agreed conditions.

The parking spot operator (PSO) owns and operates the parking spots with access to the charging infrastructure operated by the CPO. The PSO offers a parking spot where a charge point is located and can supply information on location and availability to the CPO.

The clearinghouse operator (hub operator), runs a software platform to enable data exchange between MSPs, CPOs, and NSPs*.

*The documentation of OCHP protocol also distinguishes the role of the Navigation Service Provider (NSP), similar or equivalent to the role of Charge Point Operator. It applies to service towards the EV user for searching, locating, and routing to charge points. The party may have contracts with CPOs or MSPs.

Roaming via hub - Hub’s roaming platform connects the associated partners. OCHP is used by the roaming hub e-clearing.net, but the documentation does not specify if the roaming hub should necessarily be run by e-clearing.net.

Authorization - EV owners are recognized by tokens. The eMSP supplies a list with contract IDs of registered EV users to the hub, that can later be downloaded by CPOs. If an EV is charged at a CPO, the operator’s system checks the ID against the roaming authorization list downloaded from the roaming hub.

Billing - Charge detail records (CDRs) collect charge data, hence CDRs describe the billing. The CPO exports the CDRs to the roaming hub. The hub performs a basic plausibility check. Correct CDRs are forwarded to the eMSP. In case the CDRs fail the validation of reliability check, are sent back to the CPO for the fixing. Besides, the roaming hub also archives CDRs.

Static charge point information - OCHP can be applied to show the charge point ID, CPO, charge point site owner, charge point location (name, address, geocode, type, image), nearby facilitates, link to a website, time zone, current status, scheduled availability status, accessibility, tariffs, authorization forms, payment options, charge mode, connector type, maximum power, guaranteed power, voltage, support phone number, reservation possibility, the maximum time for the reservation, languages of the interface, user feedback form, and the time of the last update. Besides, the tariff model can handle complex advanced tariff schemes based on time of the day, date, charged energy, charging speed, and duration based on input from CPO. The CPO supplies static charge point information to the roaming hub, which can be then processed and transferred to contracted EV owners by eMSP.

Real-time charge point information - OCHP provides the current status of a charge point (available, reserved, occupied, blocked, out of order, unknown). OCHP divides real-time from static data. The dynamic data is stored in a separate database, dedicated to this kind of access. Real-time charge point information is sent to the roaming hub, then is transferred to the signed users of an eMSP.

Session information - refers to CDR ID, charge point ID, token ID, contract ID, CDR status, start time, end time, duration, charge point address, charge point type, connector type, tariffs, meter ID, total cost, and currency.

Remote start/stop - Charging sessions can be controlled via an eMSP app.


The OCHPDirect (dedicated for p2p connections) supports the following functionalities:

Roaming peer-to-peer - Achieving e-roaming is possible without a connection with a hub.

Authorization - Charging sessions can be controlled via an eMSP app.

Real-time sessions information - Start of a charging session, end of a charging session, metering information, power management information, handy invoicing.

Remote start/stop - The charging process can be controlled when stationary started via the eMSP application.

E-clearing.net, unlike commercially orientated hubs, is an open platform that facilitates the exchange of roaming authorization, charge transaction, and charge point information data (all transactions are free). At the moment, e-clearing.net requires only a fee for joining the platform.


Why apply at least one open standard? To save time and open your network to a larger number of users, increase opportunities and reap profits. Or, in other words, applying open EV roaming charging software protects against being excluded from the market. Both, Open Charge Point Interface and Open Clearing House Protocol & OCHPDirect are classified as stable, reliable, and secure solutions. The growing number of countries that support the development and promotion of both solutions indicate openness, independence, and royalty-freedom. Open and modern approach contributes to fast penetration and enthusiastic approval. Many countries are in the early phase of charging infrastructure development. Open standards are meant to facilitate rapid growth and ensure up-to-date functionality.

OCPI and OCHP support installing a public open charging network

Open Charge Point Interface and Open Clearing House Protocol are developed and supervised by non-commercial organizations. Demand for roaming includes cross-border connectivity. The future of the open network will largely depend on the willingness of partners to collaborate and regulatory guidance. For instance, some countries already established conditions for operation on the domestic market. Slovakia requires new parties within three months of the commissioning of the recharging points, to be connected to any roaming platform that connects more than 80 operators. In Norway, Oslo authorities formed an open policy for sharing with third parties. Berlin expects every Charge Point Operator operating a recharging point in the public domain to register it in a central authentication platform managed by the city, offering access to the customers of each eMobility Service Provider under comparable conditions. To meet the conditions, it is necessary to open a network. Following the 2050 EU strategy, soon it might be mandatory to provide seamless connection on large networks in the Union.

An extensive scientific analysis of the four most commonly developed protocols in terms of the search for the ideal protocol can be found 

Two actively supported independent open standards for EV roaming. Discover cross-border e-mobility standards for accessible charging network.

EV roaming with open standards - OCPI and OCHP 

Actively supported two commercial open standards facilitating EV roaming.

Interoperability demands a flexible approach and cooperation between market participants. For opening the electric car charging market open standards have been established. Two are an initiative of independent associations (responsible for the development of Open Charge Point Interface and Open Clearing House Protocol). The two other open standards for EV roaming are privately held but similarly open and free to apply. Hub operators GIREVE and Hubject offer innovative customer-friendly service networks for cross-border charging. Both hubs actively support network growth. Becoming a marketplace for charge point operators, e-mobility service providers, car manufacturers, energy suppliers, and public institutions Hubject and GIREVE offer a broad range of profitable solutions and facilitated communication benefits.

Hubject’s network expands beyond Europe. At the moment hub operator connects 767 partners in 52 countries offering over 250 000 charging stations. Hubject is a joint venture of the BMW Group, Bosch, EnBW, Enel X, Mercedes-Benz, innogy, Siemens, and the Volkswagen Group. Initiated in 2012, forms now the largest pool of charging stations. Via intercharge, the dedicated e-mobility platform, provides standardized access to charging infrastructure. Besides, Hubject advises automotive manufacturers, charging providers, and other EV-related businesses launching e-mobility services or implementing Plug&Charge with ISO 15118.

GIREVE has been created as a startup by leading French players in electric mobility: Renault, CNR, la Caisse des Dépôts, EDF et Enedis. At the moment GIREVE operates on 31 European markets and offers 185 charging networks with 109 476 charging stations accessible via EV roaming. Following the open policy in November 2020 hub operator announced becoming a Full Contributor of EV Roaming Foundation (the one responsible for the development of the OCPI open standard). This provides enhanced opportunities for partners. For instance, for an operator being already OCPI compliant, there is no extra cost to connect to GIREVE. Offering two standards for interoperability enables innovation and progress for e-mobility.

OICP was designed in 2012 by Hubject - formed by leading automotive experts in Germany. Besides being the roaming platform, Hubject offers technical connection and contractual arrangements for e-roaming. The general structure of the OICP is divided into two parts - for the eMobility Service Providers and Charge Point Operators, nevertheless, the product offer is constantly being developed. Hubject proclaims the OCIP is “the most widely implemented communication standard between European eMSP and CPO systems”. The most recent version, 2.3, was released in October 2020. The newest update of the protocol follows market requirements - improves the POI quality in an upscaling market, calibration law compatibility, data process performance, and offers higher transparency on the different charging use cases. Additionally, Hubject offers helpful and relevant for CPOs set of remote testing functionalities, for complex examination of various use cases. With the recent protocol update, from July 1st, OCPI 2.1 will be withdrawn.

The protocol is publicly available at no cost and requires no registration. From May 2019, OICP became an open-source protocol, free of charge, distributed on Hubject’s website and on open code distribution systems. The aim is to include more stakeholders in the evolution of OICP. The protocol is published under the Creative Commons Attribution-ShareAlike 4.0 International License. This grants easy distribution and to be shared under the same consent. Additionally, Hubject offers Hubject-compatibility certification.

OICP is formed on SOAP (Simple Object Access Protocol) and uses an object-based approach. It’s a real-time protocol, that also offers asynchronous operations. Although a back-up database is provided, Hubject doesn’t actively support downloads to the charging station. The platform maintains a record of the transaction data.

The OICP protocol documentation establishes market roles as follows:

The EV user/owner wants to charge an EV at a charge point/charge station, and has an agreement with the eMSP.

The eMobility Service Provider wants to enable EV owners the access the charge points. In most cases, the eMSP has a valid contract and transfers information with the Charge Point Operator via Hubject’s platform. Hubject offers connection via eMSP aggregator, which enables communication with the platform. This means several eMSPs can integrate via an eMSP aggregator, hence, the sub-partners do not need to associate with Hubject.

The Charge Point Operator (CPO) manages a charge point. The operator has a signed contract and exchanges information via Hubject’s platform. Like eMSPs, several CPOs can integrate via a CPO aggregator. Appropriately the sub-partners do not need to register with Hubject, because the communication with Hubject is done via the CPO aggregator.

Hubject, being a roaming hub, facilitates communication between eMSPs and CPOs via the EV roaming platform Hubject Brokering System.

OICP supports the following functionalities:

Roaming via hub - The CPO and the eMSP system connect to based on web services Hubject B2B Service Platform. Both parties, the CPO and MSP, have an e-roaming contract through Hubject.

Ad hoc payment - ‘Intercharge direct’ is an ad hoc payment dedicated solution integrated in OICP and Hubject platform. This allows any contractless EV owner to charge up and pay at any charging station.

Authorization - Hubject links the IDs of eMSPs or CPOs and SSL certificate information. Then each does or does not authorize the charge session. Hubject’s database performs as back-up, but not actively support downloads from their database to the charging station.

Reservation - An EV owner can book a charge point e.g. via eMSP app. Hubject checks charge point compatibility with the EV.  If matches send the request to the CPO, which in return responds whether the booking was successful. A reservation can also be withdrawn.

Billing - Charge session data is recorded in Charge detail records (CDRs). Hubject passes on the CDR to the eMSP and stores the CDR in the system.

Charge point information - Uploaded charge point information can be distributed between CPOs and eMSPs via Hubject’s platform. The information areas are charge point ID, CPO, charge point name, charge point location (name, address, geocode, type), time zone, opening times, current availability, accessibility, tariffs, authorization modes, means of payment, charge mode, connector type, maximum power, hub connection, support contact number, reservation possible, real-time status information possible, predictive charge point usage, smart charging services, and the date of the last update. OICP maintains flexible pricing based on charge facility, charge point location, and time-of-use.

Real-time charge point information - This covers dynamic charge point availability status and tariff information.

Session information - Session ID, service specifics, charge point ID, authentication data, start and end time of charging, start and end time of connection, starting and stopping meter value, meter value in between, consumed energy, CPO ID, MSP ID.

Remote start/stop - From within the eMSP application, a charging session can be operated.


eMIP is designed and developed by a French start-up. Created in 2013 by leading French players in electric mobility: Renault, CNR, la Caisse des Dépôts, EDF et Enedis with the main objective to provide “open access to vehicle charging stations”. The core business of GIREVE is to offer a roaming platform for eMSPs and CPOs.

The eMobility Interoperation Protocol enables roaming via clearinghouse data. The protocol provides access to charging point databases, and smart charging features. Although the GIREVE’s main market is France, in 2017 expansion covered the connection of European operators in Austria, Germany, Netherlands, Switzerland, Sweden, UK, Italy, Romania, Norway, Czech Republic, Lettonia, Hungary, Denmark, Belgium, Spain, Slovakia, Irland, and Luxembourg. In 2018 GIREVE’s platform was made compatible with the open protocol OCPI. Currently, the roaming platform operates in 28 countries.

The most recent version, eMIP 1.0.7, was released at the end of July 2019. eMIP is open for free although requires registration. GIREVE also proposes certification services. Moreover, to join GIREVE, the before-mentioned certification is required to connect to the platform. The eMIP protocol is open and, when a partner is approved by GIREVE, allows complete benefits. This includes connecting with a different hub platform or conducting peer-to-peer connections. Note, the protocol documentation explicitly declares GIREVE as the hub platform, the eMIP in practice does not apply to peer-to-peer connections. To ensure a high level of architectural openness and up-to-date offering, GIREVE consults with stakeholders potential future functionalities. GIREVE entirely takes responsibility for the eMIP protocol, in contrast to the previously mentioned approaches (commercial and non-commercial), there is no formal eMIP-member association.

eMIP is based on SOAP (Simple Object Access Protocol). Although eMIP is designed as a real-time protocol, it also supports asynchronous operations. The peculiarity of eMIP’s architecture makes it fairly adaptable and flexible. Any new sorts of data messages, or identification methods, can quickly be added via definition tables.

eMobility Interoperation Protocol documentation defines market roles as follows:

The EV user/owner wants to charge a vehicle at a charge point and an authorization medium.

The eMobility Services Providers warrant EV owners different services amongst which EV charging service, rental, car-sharing, navigation services, etc. The eMSP has a B2C agreement with the EV owner/user and a subscription to GIREVE’s platform.

The Charge Point Operator (CPO) accesses charging infrastructure and other services to EV users/owners and has a subscription to GIREVE’s platform.

The data aggregator applies to a system controlling charging infrastructure data in a given area and which can be inquired via GIREVE’s platform.

GIREVE, as a hub, manages the eMobility Services Platform which offers and ensures technical and functional means to standard services between the eMSPs, CPOs, and data aggregators.

eMobility Interopeational Protocol supports the following functionalities:

Roaming via hub - eMSPs, CPOs, and data aggregators join, based on web services, GIREVE’s roaming platform. The protocol documentation indicates GIREVE as the hub platform.

Authorization - eMIP offers several authorization processes.

Synchronous Authorization - check-in via the charge point (e.g. with an RFID card) or via the eMSP (e.g. an app).

Asynchronous Authorisation: Authentication Data Exchange. The eMSPs upload a list of approved subscribers to GIREVE’s platform. The list can be downloaded by CPOs. When charging at the charge point, e.g. via a RFID card, the CPO verifies the ID with the list provided.

Asynchronous Authentication Data Exchange & Synchronous Authorisation covers an event when CPOs do not download the list but request GIREVE to review the EV user ID. The decision on which authorization process to implement lies at the CPO's discretion.

Reservation - An EV driver can reserve a charge point via the eMSP app. (If the option is implemented and supported)

Billing - CDRs between CPOs and eMSPs are exchanged via GIREVE’s platform. This forms the foundation for invoicing. Via Asynchronous Exchange, the eMSP can download a CDR supplied by the CPO at any time, or via Synchronous Exchange - the eMSP gets quickly a CDR uploaded by the CPO.

Static charge point information - CPOs upload charge point information to GIREVE’s platform. GIREVE verifies the CPOs contract before updating their repository. The aforementioned data can be regained by CPOs, MSPs, and data aggregators. The information hold charge point ID, CPO, charge point manufacturer, charge point name, charge point location (address, geocode, type), time zone, opening times, current availability status, scheduled availability status, accessibility, tariffs, authorization modes, payment methods, charge mode, connector type, maximum power, guaranteed power, voltage, amperage, support contact, remote start/stop possible, reservation possible, and the time of the last update.

Real-time charge point information - GIREVE’s platform receives from CPOs the current availability status of the charge point. The CPOs agreement is verified before updating GIREVE’s repository. This includes scheduled status changes (e.g. for reservation).

Charge point search - The “charge point finder” function eMSPs can retrieve a list of charge points located in a given area and fulfill a set of charging criteria, (e.g. connector type).

Session information - Recorded and sent in the CDR - Charge Detail Record, covers the session ID, CPO ID, eMSP ID, EV user ID, charge point ID, contract ID, start and end time of charging session, metering report.

Real-time session information - With offered message service, CPOs can report events to eMSPs, and eMSPs can request actions while a charging session is in progress.

Remote start/stop - A charging session can be started or terminated by the eMSP.

Platform monitoring - GIREVE’s platform introduces a monitoring ability to check whether eMSPs, CPOs, and data aggregators have a valid connection to the platform. Specially designed “Heartbeat” tests the connection. The system sends “Heartbeat” requests to the associated companies.

EV roaming charging software of the e-mobility community

Privately held protocols offer great support and match users’ expectations. Joining at least one hub will be beneficial since emobility operators and providers can easily improve services and provide a top-notch experience. GIREVE and Hubject on a road to EV roaming extend charging infrastructure with additional user-friendly features. A cross-border network is on hand, and the support of emobility experts and industry leaders ensures the coherence and sustainability of the network. Keep in mind that even though both hubs are developing their individual protocols (OICP and eMIP), they also contribute to OCPI and OCHP growth.

OICP and eMIP refine the EV charging experience

The fact that both hubs were created at the initiative of automotive leaders makes the established EV charging e-roaming solution a guarantee of stability and accelerated growth of the whole network. Besides coverage of crucial functionalities, both protocols offer and develop additional services. The proof is in the numbers. Hubject operates on more than 50 markets on 4 continents and GIREVE offers a pan-European connection in nearly 30 countries. In light of the reality that the e-mobility market is growing rapidly and 2020 was a record year for electric car sales, it is expected that the scope of both hubs will continue to expand.

Actively supported two commercial open standards facilitating EV roaming. Discover cross-border e-mobility standards for accessible charging network.

Open Charge Point Protocol

21 SEPTEMBER 2022 • 6 MIN READ