OCPI and Roaming Integration for CMS Platforms

OCPI 2.2.1 defines several modules: Locations (where chargers are and their real-time status), Tariffs (published pricing structures), Sessions (in-progress charging events shared with the driver's eMSP), CDRs (Charge Detail Records, the settlement-quality transaction that comes after a session), Credentials (the mutual authentication between CPO and eMSP), Tokens (RFID and app IDs recognised across networks).

A CPO exposes some subset of these modules; an eMSP consumes some subset. A roaming hub (Hubject, Gireve) sits in the middle for many networks; direct peer connections work for large partners.

Roaming hubs simplify onboarding: connect once, reach every hub member. The cost is a per-session or per-CDR fee to the hub. Direct peer connections eliminate that fee but require you to run and maintain a bilateral integration with each partner.

Practical choice: connect to a hub first for coverage, add direct peers with the highest-volume partners over time. The CMS should support both patterns simultaneously without duplicating session logic.

CDRs are the money layer. A driver charges on network A with an eMSP-B contract; A generates a CDR, eMSP-B receives it, eMSP-B pays A (via the hub or directly), eMSP-B invoices the driver. Reconciliation between what your CDRs claim and what you actually received is a full-time job at scale.

The CMS needs a reconciliation service that flags mismatches, tracks disputes, and integrates with your finance system. Building this in from the start beats bolting it on later.

• CPO (Charge Point Operator): owns the chargers and produces location, session and CDR data
• eMSP (e-Mobility Service Provider): owns the driver relationship, authorization and end-user billing
• Roaming Hub: connects many CPOs with many eMSPs, so each connects once
• NSP (Navigation Service Provider): consumes location and availability data for driver apps

• Locations (site metadata) and EVSEs (individual chargers)
• Connectors (each physical outlet on an EVSE)
• Tariffs (published pricing structures)
• Sessions (in-progress charging events shared with the driver's eMSP)
• CDRs (settlement-quality Charge Detail Records)
• Credentials (mutual authentication between CPO and eMSP)
• Tokens (RFID and app IDs recognised across networks)

• Missing CDRs the driver claims to have used
• Tariff mismatch between what the driver saw and what got billed
• Currency and exchange-rate errors across borders
• Timezone errors on session start and stop times
• Duplicate sessions on retry
• Disputed stop times when charger and eMSP disagree