What is the difference between OCPP and OCPI?

OCPP connects a charger with its own operator's backend. OCPI connects companies, so operators and card providers can exchange card lists, tariffs and session records.

Explained in

EV charging fundamentals · Stop 03What happens after you tap your card?Follow one tap from the card reader to the operator's backend and, for another company's card, across the roaming route and back. OCPP and OCPI in action.
  • OCPP connects the charger with its own operator's backend: status, meter values, authorisations, start and stop.
  • OCPI connects companies: operators and card providers exchange card lists, tariffs, locations and session records.
From “Two protocols with two jobs”, stop 03

Terms

  1. OCPPOpen Charge Point Protocol: the open protocol between a charger and its operator's backend.
  2. OCPIOpen Charge Point Interface: an open protocol for roaming between operators and e-mobility service providers.
  1. What happens when I tap my charging card?The charger asks its operator's backend whether the card may charge. For another company's card, the backend checks it with the roaming partner. The approval usually comes back within two seconds.
  2. How can my card work at another company's charger?Through roaming: operators and card providers exchange card lists, prices and session records, directly or through a roaming hub, and settle in the background.
  3. Why does charging involve so many companies?Three things spread the work: the grid connection, the location where people park, and contracts that work across many networks. One company can hold several roles, but the roles stay separate.
  4. How many public charge points are there in Europe?More than 1.1 million in the EU alone: the European Alternative Fuels Observatory counted 1,159,838 public recharging points in August 2026. The map on this site covers part of the network: 839,000 public charge points at 227,000 sites across Europe, from national registries and OpenChargeMap.
  1. Open Charge Alliance: Open Charge Point Protocol (OCPP). https://openchargealliance.org/protocols/open-charge-point-protocol/. Checked 07 Oct 2026.
  2. EVRoaming Foundation: Open Charge Point Interface (OCPI). https://evroaming.org/ocpi-background/. Checked 07 Oct 2026.