If you want your chargers to be usable by customers of many e-mobility providers, you will meet two acronyms: OCPI and OICP. OCPI is an open protocol for direct and hub-based roaming. OICP, the Open InterCharge Protocol, is the protocol used to connect to Hubject, one of the largest roaming platforms. This guide explains what OICP does and when you need it.
- OICP is the protocol for connecting CPOs and EMPs to the Hubject platform, which routes data between them.
- It covers EVSE data, live status, authorisation, remote start and stop, charge detail records, pricing and notifications.
- Recent versions use REST and JSON, with mutual TLS certificates for security.
- OICP is hub-centric; OCPI supports both peer-to-peer and hub connections.
What OICP is
OICP was created by Hubject to exchange roaming data through its platform. Unlike OCPI, where partners can talk directly to each other, OICP messages always go through the Hubject platform, which forwards them to the right partner according to the contracts activated in its marketplace. The protocol specification is published openly, while the platform and contracts are operated by Hubject. For the bigger picture on hubs, read EV roaming hubs explained.
Roles in OICP
| Role | OICP name | Responsibilities |
|---|---|---|
| Charge point operator | CPO | Publishes EVSE data and status, requests authorisation, sends CDRs |
| E-mobility provider | EMP | Authorises its customers, can start and stop remotely, receives CDRs |
| Platform | Hubject | Routes messages, manages contracts, offers clearing services |
The difference between these market roles is covered in our article on CPO vs eMSP.
Main OICP services
EVSE data and status
CPOs push static data about each EVSE, such as address, coordinates, plugs, power and accessibility, to the platform. Live status like available, occupied or out of service is pushed separately so EMP apps can show it in real time. Each EVSE is identified by its EVSE ID.
Authorisation
When a driver taps an RFID card, the CPO sends an authorise start request to the platform, which forwards it to the EMP that issued the card. The answer comes back within seconds. For remote start via an app, the EMP sends a remote start request that the platform forwards to the CPO, which starts the session through OCPP.
Charge detail records
After the session, the CPO sends a CDR with identification, times, energy and meter values. The platform forwards it to the EMP and can use it for clearing. See charge detail records for best practice.
Pricing
Recent OICP versions let CPOs publish pricing products and EVSE-specific prices to EMPs, so that EMPs can show drivers the price before they charge and bill consistently.
Reservation and notifications
OICP supports remote reservation where both partners agree, and charging notifications that tell the EMP when charging starts, progresses, ends or fails. This allows EMP apps to display live session information.
Plug & Charge
Hubject also operates a public key infrastructure for ISO 15118 Plug & Charge. Through it, contract certificates can be provisioned so that cars identify themselves automatically when plugged in, without card or app.
Technical basics
- Transport: current versions use RESTful HTTPS with JSON; older versions used SOAP.
- Security: mutual TLS with certificates issued for the platform connection.
- Identification types: RFID, remote identification, QR code and Plug & Charge.
- Testing: a pre-production environment is available before going live.
OICP vs OCPI
| Aspect | OICP | OCPI |
|---|---|---|
| Governance | Maintained by Hubject | Maintained by the EVRoaming Foundation |
| Topology | Hub-centric, via Hubject | Peer-to-peer or through hubs |
| Contracts | Activated in the platform marketplace | Bilateral or via a hub |
| Live sessions | Charging notifications | Sessions module |
| Smart charging | Limited | ChargingProfiles module |
| Typical use | Reach Hubject's partner network | Direct partners and OCPI-based hubs |
Neither protocol replaces OCPP, which still connects each charger to your CSMS. See OCPI vs OCPP for how these layers fit together.
Do you need OICP?
You need OICP if you decide to connect to Hubject's platform directly. Some operators reach the same partners through other hubs or direct OCPI links instead. Decide based on which EMPs your drivers use, the commercial terms and your platform's capabilities. Many networks combine several connections.
Frequently asked questions
Is OICP free to use?
The specification is publicly available, but connecting to the Hubject platform requires a commercial agreement and platform fees.
Can a CPO use OICP and OCPI at the same time?
Yes. Many CPOs connect to Hubject with OICP and to other partners or hubs with OCPI, as long as their platform keeps tariffs, statuses and CDRs consistent.
Does OICP work with OCPP 1.6J chargers?
Yes. OICP operates between back-office systems, so the charger protocol does not matter. The CSMS translates between OCPP and OICP.
Üreticy connects chargers via OCPP and partners via OCPI roaming, with complete message logs. Explore the platform or talk to us about your roaming plans.