EV Charging Interoperability: Data Roaming Was Step One. Financial Roaming Is Step Two.

The conclusion first: EV charging interoperability as the industry currently understands it is half the problem, solved well. OCPI handles data exchange between CPOs and Demand Partners. ISO-15118 handles vehicle-to-charger authentication. Plug and Charge makes the driver experience seamless at the point of delivery. The technical handshake works. What does not work — and what the industry has been quietly hoping someone would solve — is the financial layer beneath that handshake. The way money moves between participants in a charging session, across currencies, across jurisdictions, across compliance regimes, is still held together by bilateral roaming contracts, slow settlement cycles, and manual reconciliation. EV charging interoperability is real at the data layer and incomplete at the financial layer. NetworkCore is the platform building the second half.

What "interoperability" has meant in EV charging so far

The past decade of work on EV charging interoperability has produced something genuinely impressive. A driver from one country can arrive at a charger in another country, plug in, and complete a session without owning a separate account or downloading a separate app. The technical mechanics that make this possible — protocol-level data exchange between operator systems, real-time authorisation requests, cross-network session reporting, vehicle-level authentication — are now mature, standardised, and operating at meaningful scale.

OCPI is the connective tissue that gets most of the credit. As the open protocol for exchanging session data, tariffs, availability, and Charge Detail Records between CPO and eMSP systems, it has become the de facto standard for charging interoperability across Europe, Latin America, and increasingly Asia and North America. CPOs publish their stations through OCPI. Demand Partners read those stations through OCPI. Sessions complete and CDRs flow back through OCPI. The technical interoperability picture is, by 2026, largely solved.

ISO-15118 extends this further into the vehicle. Plug and Charge — the application of ISO-15118's authentication capability to public charging — eliminates the need for the driver to interact with the charger at all. The vehicle and the charger negotiate authentication directly. The driver plugs in. The session begins. The technical interoperability is now invisible to the user, which is exactly the standard mature interoperability is supposed to reach.

This is what most of the industry means when it says EV charging interoperability. And it is real. It is also only half of what the term should mean.

What interoperability has not yet solved: the money

Beneath every interoperable charging session, a financial flow has to happen. The driver pays for the energy. The CPO receives the wholesale value of what they delivered. The eMSP or Demand Partner receives whatever revenue share the commercial arrangement specifies. The platform sitting in the middle takes its commission. The tax authority receives the appropriate VAT. In cross-border sessions, currency conversion has to happen. In multi-jurisdiction operations, the correct compliance rules have to apply per session per fee type per country.

This is the financial layer of EV charging interoperability — and it is where the current industry stack is held together by bilateral commercial arrangements, slow settlement cycles, and manual back-office processes that do not scale.

In the dominant model today, a CPO and an eMSP agree wholesale pricing through bilateral negotiation. The eMSP marks up that wholesale price and presents a different number to the driver. Settlement happens on cycles that frequently stretch to 30 or 60 days. VAT is applied according to the jurisdiction of the charging location, with each Demand Partner responsible for handling its own multi-country compliance. Cross-border FX is managed through manual treasury operations. Reconciliation between session records and invoice flows is a continuous back-office burden, increasing in proportion to the number of countries the operator works in.

This is interoperability at the data layer with bespoke commercial arrangements at the financial layer. It is not interoperable in the sense that telecom roaming is interoperable. It is technically connected and commercially fragmented. And it is the structural reason EV charging interoperability at scale has remained difficult to deliver as a clean, commercially predictable product.

The industry has been quietly waiting for the second half of interoperability to be built. Financial roaming. The money equivalent of OCPI. The layer that lets every participant in the charging value chain transact with every other participant without negotiating a bespoke commercial relationship for each connection. EV charging interoperability is genuinely interoperable only when this layer exists and operates at the same standard as the data layer.

Why financial interoperability is the harder problem

Building EV charging interoperability at the financial layer is structurally harder than building it at the data layer for reasons worth being explicit about.

Data interoperability requires a protocol. Once the protocol is agreed and adopted, the technical handshake works. The protocol does not need to know about regulatory regimes. It does not handle money. It does not have legal opinions on VAT classification or jurisdiction-specific invoicing requirements. It defines a structured way for systems to exchange information and lets implementers handle the rest. OCPI is enormously valuable precisely because it is narrow.

Financial interoperability requires far more than a protocol. It requires a regulated entity capable of holding funds in the appropriate jurisdictions, with the licences to do so. It requires a payment infrastructure capable of capturing money from drivers, allocating it correctly across multiple parties per session, and settling those allocations across currencies and across borders on short cycles. It requires a tax engine capable of applying the correct VAT or GST or sales tax treatment to each fee element of a session in the country where the session occurred. It requires invoicing infrastructure that produces the formats each tax authority demands, in the languages the regulatory regime accepts, with the audit trail every jurisdiction requires for retention. It requires AML and KYC processes for every participant, transaction monitoring at session level, and the operational discipline to maintain compliance as rates and rules change.

A protocol cannot do any of this on its own. EV charging interoperability at the financial layer is a regulated infrastructure product, not a standards initiative. It has to be built. Someone has to build it. And the absence of an obvious entity to build it is part of why the financial layer of interoperability has lagged the data layer for so long.

What financial interoperability looks like when it is delivered correctly

A real financial layer of EV charging interoperability has specific characteristics, and naming them helps clarify what the industry is actually missing.

It connects every participant on the network to every other participant through the platform. A CPO joining the network is immediately accessible to every Demand Partner. A Demand Partner integrating is immediately able to settle sessions at every CPO. No bilateral commercial agreements per pair of counterparties.

It applies a transparent commercial model. A defined revenue split that every participant can read in advance, with no opaque margin extracted from any layer of the chain. Public pricing as the baseline that every driver sees. Optional negotiated commercial arrangements between specific pairs of participants — layered on top of the public pricing baseline, transparently configured, applied with full audit evidence — for cases where the bilateral economics warrant it.

It settles on a short, predictable cycle. Sessions complete, money moves, and every participant receives their share within a defined timeframe — measured in hours and days rather than weeks and months. This is what real financial roaming feels like and it is the operational benchmark EV charging interoperability at the financial layer needs to meet.

It handles every operational layer beneath the integration: payment capture, currency conversion, revenue allocation, invoicing per jurisdiction, VAT and GST application per session per fee type, compliance documentation, audit evidence, retention, AML and KYC. None of this is delegated back to the participants. The platform's purpose is to absorb it.

When all of this works together, EV charging interoperability is no longer just data exchange between systems. It is genuine end-to-end interoperability — technical and financial — at the standard the industry's first decade of work on this category promised but has not until now delivered.

What this means for Demand Partners: one plug adds all the value

The implication of complete EV charging interoperability for Demand Partners — fleets, OEMs, fintechs, wallets, super-apps, mobility platforms, insurance companies, every category of business with EV-driving users — is the most consequential commercial change in the EV charging market in years.

Through a single integration, the Demand Partner gains access to the entire CPO network connected to the platform. Every CPO the platform onboards is immediately reachable to every Demand Partner without the Demand Partner negotiating, integrating, or contracting with that CPO bilaterally. Coverage scales for the Demand Partner without any work on their side. The network effect that bilateral roaming has historically promised but never structurally delivered becomes real.

The Demand Partner does not handle multi-jurisdiction compliance. It does not run a reconciliation operation. It does not invoice CPOs per session. It does not manage FX across markets. It does not maintain a compliance team for charging. All of this is absorbed by the platform layer beneath the integration. The Demand Partner offers charging as a feature. The feature works. Sessions earn per-session revenue. The integration is, in operational terms, completely passive.

The Demand Partner can build its own charging UI through the API or use a complete drop-in iframe — its choice. It can stay inside its existing PSP and ecosystem or run autonomously on the platform's infrastructure — its choice. The integration depth matches the Demand Partner's preference. The operational outcome is the same: interoperable charging access across every market the platform covers, earning per session, with passive operations.

This is what EV charging interoperability is supposed to mean in commercial terms for Demand Partners. One plug. Everything connected on the other side of it. Every benefit the data interoperability layer promised, plus everything the financial layer was always supposed to deliver and never quite did.

What this means for CPOs: one more distribution channel that opens the gates

The same EV charging interoperability infrastructure delivers a different but equally consequential value for CPOs.

A CPO joining the platform integrates once and gains access to demand from every Demand Partner on the network, across markets, without bilateral negotiations. The CPO is not signing wholesale agreements per eMSP. It is not running a corporate-account onboarding operation. It is publishing its stations once, through the platform, and gaining demand routing from every distribution partner connected on the other side of it.

This is, in commercial terms, a new distribution channel — and it is additive to whatever roaming relationships the CPO already has in place. The platform integrates alongside the CPO's existing CSMS via OCPI, in the same way the CPO already manages other roaming connections. There is no operational disruption. There is no replacement of existing partner relationships. There is one additional channel, configured once, generating sessions from a network of Demand Partners the CPO would have to negotiate with individually under the bilateral model.

The commercial mechanics for the CPO are clean. Sessions routed through the platform settle within 48 hours, in the CPO's local currency, at the CPO's published public tariff — no intermediary markup, no opacity, no decoupling between what the driver sees at the charger and what is reported through the financial flow. Where the CPO wants to negotiate a preferential rate with a specific Demand Partner — a fleet operator with significant volume in the CPO's geography, an OEM whose drivers concentrate on the CPO's corridors, a wallet whose user base would benefit from a loyalty rate — the platform supports configuring those bilateral arrangements transparently on top of the public pricing baseline.

What this opens up for the CPO is the structural benefit of network effects working in their favour rather than being captured by the layer above them. As the platform adds more Demand Partners, every existing CPO on the network gains access to more demand without any additional integration work. As the platform expands across geographies, the CPO's stations become accessible to drivers from new markets without the CPO setting up bilateral relationships in those markets. EV charging interoperability at the financial layer turns the CPO's distribution surface into something that compounds with the platform's growth, rather than something they have to fight to extend bilaterally.

NetworkCore: the financial roaming layer

NetworkCore is the platform building EV charging interoperability at the financial layer to the standard the industry's first decade of work on the data layer set as the benchmark. The technical interoperability the market already has — OCPI, ISO-15118, Plug and Charge — is the foundation. The financial interoperability NetworkCore provides is the layer that makes the foundation produce a working commercial outcome end to end.

For Demand Partners, the platform delivers what one-plug EV charging interoperability was always supposed to mean: a single integration that produces access to every CPO on the network, with the entire transaction lifecycle handled beneath the integration, with complete operational passivity after deployment. The companion guides worth pairing with this post: EV Charging Roaming explains the data-layer roaming context this builds on; EV Charging Settlement Layer covers the financial settlement function specifically; EV Charger Platform vs Roaming Hub clarifies the difference between traditional roaming and the financial layer above it; and EV Charging Transaction Platform defines the broader category this offering sits inside.

For CPOs, the platform delivers what financial interoperability should mean from the operator's perspective: one additional distribution channel, integrated once via OCPI alongside existing CSMS infrastructure, opening access to a network of Demand Partners that grows continuously, with public price preserved, settlement on a short cycle, and the option to layer negotiated bilateral commercial arrangements where the strategic relationship warrants it.

For the broader market, the platform delivers the second half of the interoperability story the industry has been telling for ten years and has only ever partially completed. Data roaming was step one. Financial roaming is step two. The technical handshake is solved. The money is now solved too.

The position to take

If you are anywhere in the EV charging ecosystem — operating chargers, building a Demand Partner product, advising clients on how to navigate this market, or evaluating where the next wave of value is going to accumulate — the framing worth taking seriously is that EV charging interoperability is no longer a single problem. It is two problems with two different maturity levels.

The first is mature and works. The second is what NetworkCore exists to build. The participants — CPOs and Demand Partners — who connect to the platform now are the ones positioning themselves on the right side of the second half of the interoperability story.

Reach the team at networkcore.org to discuss how the integration would work for your position in the market.