What do CPO and eMSP exchange in OCPI?
Five minutes before the driver arrives, the provider's app already shows the Austrian site: six chargers, four available, the price per kWh.
That information came from the operator, through OCPI, long before anyone plugged in.
The questionWhat do the two companies exchange, and when?
| Sent by | When | |
|---|---|---|
| Locationssites, chargers, connectors, live status | CPO | always |
| Tariffsprices and their structure | CPO | before |
| Tokenscards and app accounts | eMSP | before |
| Commandsstart or stop from an app | eMSP | during |
| Sessionsthe running session | CPO | during |
| CDRsthe record for billing | CPO | after |
OCPI also has modules for charging profiles, hub client information and, since 2.3.0 edition 2, invoice reconciliation.
Before, during, after
- Before the session, the operator publishes its sites and prices; the provider shares the its customers may use.
- During the session, the operator reports its progress, and the provider can send commands, for example a start from the app.
- After the session, the operator sends the that both sides bill from.
describes this as real-time information about location, availability and price, and a uniform way to exchange data before, during and after the transaction.
Check your understanding
3 questions. Answer all of them to complete this stop. Each answer explains itself.
Which side sends the Locations module data?
The operator knows its sites, chargers and status, and publishes them to its partners.
Which module carries the record that both sides bill from?
The charge detail record is sent by the operator after the session and is the basis for billing.
Why does the provider's app know the price before the driver arrives?
Tariffs are exchanged before any session, so apps can show them.
- OCPI Open Charge Point Interface: an open protocol for roaming between operators and e-mobility service providers. EV charging fundamentals, stop 03 Glossary
- CDR Charge detail record: the digital receipt of a session, with energy, duration and tariff. EV charging fundamentals, stop 05 Glossary
- Token In OCPI, what a driver starts a session with, such as a charging card, a key fob or an app account; it carries the contract ID of the driver's provider. Stop 04 Glossary
- EVRoaming Foundation: OCPI 2.3.0, introduction and background. https://github.com/ocpi/ocpi/blob/2.3.0/release/core/introduction.asciidoc. Checked 09 Oct 2026.
- EVRoaming Foundation: OCPI 2.3.0, introduction and background. https://github.com/ocpi/ocpi/blob/2.3.0/release/core/introduction.asciidoc. Checked 09 Oct 2026.