{"id":4369,"date":"2026-05-28T14:55:40","date_gmt":"2026-05-28T14:55:40","guid":{"rendered":"https:\/\/trendpowercharge.com\/?p=4369"},"modified":"2026-09-29T10:03:31","modified_gmt":"2026-09-29T10:03:31","slug":"ocpi-vs-ocpp-vs-iso-15118","status":"publish","type":"post","link":"https:\/\/trendpowercharge.com\/en_gb\/ocpi-vs-ocpp-vs-iso-15118\/","title":{"rendered":"OCPI vs OCPP vs ISO 15118: EV Charging Protocols Explained for CPOs and Charger Manufacturers"},"content":{"rendered":"
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Quick Answer: OCPI vs OCPP vs ISO 15118<\/h2>

OCPP, OCPI and ISO 15118 are three important EV charging protocols, but they do not do the same job.<\/p>

OCPP connects charging stations with a backend charging management system. It helps operators monitor chargers, manage transactions, control charging sessions, update firmware and troubleshoot issues remotely.<\/p>

OCPI connects charge point operators with e-mobility service providers, roaming platforms and partner networks. It helps exchange location data, tariffs, tokens, session data and charge detail records for roaming and partner access.<\/p>

ISO 15118 connects the electric vehicle and the charger. It enables advanced vehicle-to-charger communication, including authentication, smart charging support and Plug & Charge.<\/p>

In simple terms: OCPP is for charger-to-backend communication, OCPI is for operator-to-partner communication, and ISO 15118 is for EV-to-charger communication. They are complementary, not direct replacements for one another.<\/p>

For CPOs, charger manufacturers and EV charging software<\/a> buyers, understanding OCPI vs OCPP is not only a technical question. It is a business decision about interoperability, roaming, user experience and long-term network scalability.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Why EV Charging Protocols Matter for Interoperability<\/h2>

EV charging interoperability means different chargers, software platforms, vehicles, apps and payment systems can work together reliably.<\/p>

Without open and well-supported protocols, a charging network can quickly become difficult to scale. A CPO may be locked into one charger vendor. A charger manufacturer may struggle to integrate with multiple software platforms. An eMSP may not be able to access charging locations or tariff data. Drivers may face failed sessions, unclear pricing or too many apps.<\/p>

This is why EV charging protocols are central to the growth of public, commercial and fleet charging networks.<\/p>

For a CPO, protocol support affects:<\/p>

  • Which charger brands can be connected to the backend<\/li>
  • Whether chargers can be monitored and controlled remotely<\/li>
  • Whether drivers can access stations through roaming partners<\/li>
  • Whether tariffs and session data can be exchanged accurately<\/li>
  • Whether the network can support future features such as Plug & Charge<\/li><\/ul>

    For a charger manufacturer, protocol support affects:<\/p>

    • Which markets the charger can enter<\/li>
    • Which charging management systems it can connect with<\/li>
    • Whether customers see the hardware as future-ready<\/li>
    • How easily the charger can pass integration and certification processes<\/li>
    • Whether the charger can support advanced user experiences<\/li><\/ul>

      For software buyers, protocol support affects the flexibility of the entire EV charging business. A strong charging management system should not only manage chargers today. It should also support roaming, payment workflows, partner integrations and future protocol requirements as the market evolves.<\/p>

      To understand backend platform capabilities in more detail, read our CPMS Complete Guide.<\/p>

      What Is OCPP?<\/h2>

      OCPP stands for Open Charge Point Protocol. It is one of the most widely used EV charging protocols for communication between charging stations and a central backend system.<\/p>

      In a typical charging network, the charger does not operate alone. It needs to send information to the backend and receive instructions from the backend. This is where OCPP plays a key role.<\/p>

      OCPP allows a charger to communicate with a charging management system for tasks such as:<\/p>

      • Starting and stopping charging sessions<\/li>
      • Sending meter values and transaction data<\/li>
      • Reporting charger status<\/li>
      • Managing errors and diagnostics<\/li>
      • Updating firmware<\/li>
      • Supporting remote commands<\/li>
      • Enabling smart charging functions<\/li>
      • Handling authorization with RFID, apps or other methods<\/li><\/ul>

        For CPOs, OCPP is the foundation of day-to-day charging network operation. If a charger cannot communicate properly with the backend, the operator may lose visibility into availability, revenue, faults and customer experience.<\/p>

        For charger manufacturers, OCPP support is often essential for commercial sales. Many CPOs and software vendors expect chargers to support OCPP because it reduces vendor lock-in and improves interoperability.<\/p>

        However, OCPP is not mainly a roaming protocol. It does not primarily connect a CPO to an eMSP. It focuses on communication between the charging station and the backend charging management system.<\/p>

        For a deeper look at different protocol versions and their business impact, read our OCPP version comparison article.<\/p>

        What Is OCPI?<\/h2>

        OCPI stands for Open Charge Point Interface. It is a protocol designed to support communication between charge point operators, e-mobility service providers and roaming platforms.<\/p>

        If OCPP is about managing chargers, OCPI is about making charging networks accessible through partner ecosystems.<\/p>

        For example, a CPO may own and operate charging stations. An eMSP may provide a driver-facing app, RFID card or subscription service. Through OCPI, the eMSP can access the CPO\u2019s charging location data, pricing information, availability, session status and billing-related records.<\/p>

        OCPI can support data exchange for:<\/p>

        • Charging locations<\/li>
        • Connector information<\/li>
        • Real-time availability<\/li>
        • Tariffs<\/li>
        • Tokens<\/li>
        • Sessions<\/li>
        • Charge detail records<\/li>
        • Roaming agreements<\/li>
        • Partner access<\/li><\/ul>

          This makes OCPI especially important for public charging networks, highway charging operators, regional charging groups, white-label networks and eMSPs that want to offer drivers broader access.<\/p>

          For CPOs, OCPI can help increase charger utilization by making stations visible to more users through partner apps and roaming networks. It can also reduce manual partner integrations by using a standardized interface.<\/p>

          For eMSPs, OCPI helps provide drivers with location discovery, pricing transparency and charging access across multiple CPO networks.<\/p>

          However, OCPI does not control chargers directly. It does not replace the backend charging management system. It works at a different layer of the EV charging ecosystem.<\/p>

          If you are building a branded charging network with partner access, explore our White Label EV Charging Software.<\/p>

          What Is ISO 15118?<\/h2>

          ISO 15118 is a communication standard between the electric vehicle and the charging station. It is especially known for enabling Plug & Charge, where the driver can connect the vehicle to a compatible charger and the system can automatically handle authentication and authorization.<\/p>

          Unlike OCPP and OCPI, ISO 15118 is not mainly about backend software integration or roaming between operators. It focuses on the communication between the EV and the EVSE.<\/p>

          ISO 15118 can support use cases such as:<\/p>

          • Vehicle-to-charger communication<\/li>
          • Secure identification<\/li>
          • Plug & Charge<\/li>
          • Smart charging communication<\/li>
          • Energy transfer coordination<\/li>
          • Support for future vehicle-grid interaction scenarios<\/li><\/ul>

            For drivers, the most visible benefit is convenience. Instead of opening an app, scanning a QR code or tapping an RFID card, a Plug & Charge experience can allow the vehicle and charger to exchange the required information automatically.<\/p>

            For CPOs, ISO 15118 can improve the charging experience and support premium network positioning. For charger manufacturers, ISO 15118 support can make hardware more attractive for markets where Plug & Charge and advanced communication are becoming important requirements.<\/p>

            However, it is important not to oversimplify Plug & Charge. It does not work with software alone. It requires support across the vehicle, charger, certificates, backend systems and payment or contract ecosystem. A CPO planning for Plug & Charge should evaluate hardware capability, software readiness, certificate handling and partner compatibility together.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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            OCPI vs OCPP vs ISO 15118 Comparison Table<\/h3>\t\t\t\t<\/div>\n\t\t\t\t
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