What is OCPI?

OCPI stands for Open Charge Point Interface. It is an open protocol that lets charge point operators (CPOs) and e-mobility service providers (eMSPs) exchange the information needed for EV charging roaming.

A CPO operates charging infrastructure. An eMSP provides the driver’s account, app, RFID card or other service. OCPI allows a driver with one provider to find and use a charger operated by another, subject to the commercial agreements and access rules between those businesses.

The official OCPI repository, maintained by the EV Roaming Foundation, lists OCPI 2.3.0 as the latest official release. Parties still need to agree the same supported version and modules for an integration.

How EV charging roaming works

A typical roaming flow has several stages:

  1. The CPO shares charger locations, connector details, availability and tariffs.
  2. The eMSP shows eligible chargers and prices to its customers.
  3. The driver presents a token or sends a start command through the eMSP.
  4. The CPO backend checks or receives the authorisation and tells the charger to start.
  5. Session updates pass from the CPO to the eMSP while charging continues.
  6. After the session, the CPO sends a charge detail record with the energy, time, price and other agreed fields.
  7. The eMSP bills the driver, and the businesses settle according to their contract.

The connection can be direct between two parties or routed through a roaming hub. A hub reduces the number of bilateral technical connections, but it does not remove the need for commercial, support and data-governance agreements.

What information OCPI exchanges

OCPI is divided into modules. Common modules cover credentials, locations, tariffs, tokens, sessions, charge detail records and remote commands. This separates current session updates from the final record used for billing and reconciliation.

Not every implementation exposes every optional function. Operators should test data freshness, identifiers, tariff interpretation, time zones, currency, taxes, command responses and correction processes with each partner.

OCPI versus OCPP

OCPP and OCPI are complementary:

  • OCPP connects a charging station to a charging station or charge point management system.
  • OCPI connects the business platforms of CPOs, eMSPs and, where used, roaming hubs.
  • ISO 15118 covers communication between the EV and charging equipment.

A roaming start request may travel from an eMSP to a CPO backend over OCPI. The CPO’s CPMS then sends the appropriate command to the charger over OCPP. Keeping this boundary clear helps teams diagnose whether a failure sits with the driver account, roaming connection, backend or charger.

EV charging management software: how CSMS and CPMS platforms work

Hands holding black amina charger showing cable connections and connectors

2026 – 14.01

– Charge Point Operations, Technology

EV Charging Management Software: How CSMS and CPMS Platforms Work

Read more

What OCPI does not guarantee

OCPI standardises data exchange; it does not guarantee that every driver can use every charger. Coverage depends on partner agreements, token acceptance, price publication and live system availability. It also does not set the retail price, process card payments by itself or settle money between companies.

Drivers may see an eMSP price that differs from the CPO’s direct price because the customer relationship and commercial terms differ. Consumer information must therefore be clear before a session starts.

Where amina fits

amina charging stations connect to the operator’s chosen CSMS over OCPP. The amina CSMS integration guide shows this direct charger-to-CSMS topology. OCPI, when required, sits beyond the charger between the CPMS and other roaming or service platforms.

This separation lets the charger remain focused on safe charging, local controls and OCPP communication while specialist platforms manage accounts, roaming, tariffs and settlement.