Connectors & Protocols
OCPP vs OCPI vs OICP: Which Protocol Does What
OCPP links chargers to their back end; OCPI and OICP link operators to roaming partners. What each protocol does and what charger buyers check.
- Prepared by
- VULTAE Engineering Team
- Published
- Reading time
- 3 min
- Sources
- 3 references
Key takeaways
- 1OCPP is the protocol between a charger and its management system (CPMS). OCPI and OICP are protocols between companies: they let a driver of one network charge at another network’s chargers — roaming.
- 2OCPI is a peer-to-peer protocol maintained by the EVRoaming Foundation; OICP is the protocol of Hubject’s roaming hub. Many networks use both.
- 3As a charger buyer, you choose OCPP support in the hardware; OCPI and OICP are features of your CPMS. Ask the CPMS provider which roaming connections it supports.
- 4Roaming brings more drivers to your chargers — useful for utilization — at the cost of roaming fees and data exchange agreements.
Contents
Short answer: OCPP connects a charger to its own back end. OCPI and OICP connect companies to each other so that a driver from one network can charge at another’s stations — roaming. OCPI is a peer-to-peer protocol from the EVRoaming Foundation; OICP is the protocol of the Hubject roaming hub. As a charger buyer you choose OCPP in the hardware; roaming is a feature of your CPMS.
Who talks to whom
| Protocol | Link | Maintained by | What it carries |
|---|---|---|---|
| OCPP | Charger ↔ CPMS | Open Charge Alliance (also IEC 63584) | Start/stop, status, meter values, smart charging, firmware, configuration |
| OCPI | CPMS ↔ e-mobility service provider or other operators | EVRoaming Foundation | Locations, tariffs, sessions, charge detail records, tokens, remote commands |
| OICP | CPMS ↔ Hubject hub | Hubject | Authorisation, charge detail records, locations, Plug & Charge services |
| ISO 15118 / DIN 70121 | Vehicle ↔ charger | ISO / DIN | Charging parameters, Plug & Charge identification |
Peer-to-peer or hub
| OCPI (peer-to-peer) | OICP (hub) | |
|---|---|---|
| Connections | One connection per partner | One connection to the hub reaches all its partners |
| Cost | Integration per partner; no hub fee | Hub fees; less integration work per partner |
| Typical users | Operators and providers with direct partnerships | Operators wanting wide reach quickly |
Many operators use both — direct OCPI links with major partners, and a hub for broad coverage. OCPI can also be used through other hubs.
What charger buyers need to check
| Item | Where it lives | Question |
|---|---|---|
| OCPP version and features | Charger firmware | 1.6J or 2.0.1? Tested with my CPMS? — see OCPP 1.6J vs 2.0.1 |
| Roaming connections | CPMS | Which OCPI partners and hubs are connected? |
| Plug & Charge | Car, charger and back end | ISO 15118 support in the charger; certificate services in the back end — see ISO 15118 |
| Tariff data | CPMS | Are prices published correctly to roaming partners? |
Roaming and utilization
Roaming lets drivers use the app or card they already have. For a new network, that can mean many more sessions than its own app would bring — helpful for utilization. The trade-offs are roaming fees and data-sharing agreements; set prices so roaming sessions still cover your costs — see how to price EV charging.
VULTAE chargers connect over OCPP 1.6J / 2.0.1 to the CPMS of your choice, which handles OCPI or OICP roaming — see charge point management software.
Questions buyers ask
- What is the difference between OCPP and OCPI?
- OCPP connects a charging station to its own management system. OCPI connects two companies — typically a charge point operator and an e-mobility service provider — so that drivers from one can use the other’s chargers, with location, tariff, session and billing data exchanged automatically.
- What is OICP?
- OICP (Open InterCharge Protocol) is the protocol used to connect operators and e-mobility service providers to the Hubject roaming platform. Instead of many one-to-one connections, each party connects once to the hub.
- Do my chargers need to support OCPI?
- No. Chargers support OCPP; OCPI and OICP are handled by the back-end software. Choose a CPMS that offers the roaming connections your drivers need.
- Why should a charging network join roaming?
- Roaming lets drivers with other networks’ apps and cards charge at your stations, which raises utilization. In return you pay roaming fees and share data. Many public networks consider roaming essential.
References
- [1]Open Charge Point Protocol (OCPP). Open Charge Alliance.
- [2]OCPI — Open Charge Point Interface. EVRoaming Foundation.
- [3]Open InterCharge Protocol (OICP). Hubject (GitHub).
