How charge point operators scale networks with OCPI and roaming

At a glance: 

• Fragmented EV charging markets force drivers to juggle multiple apps and cards, leading to compatibility issues across charge point operators 

• Roaming agreements and open protocols like OCPI allow for a smooth charging experience across networks 

• OCPI is a common technical language for charge point management systems to communicate without conversion delays or data loss 

• Roaming increases network utilisation, expands market reach for CPOs and MSPs, and delivers the seamless experience EV drivers expect 

Imagine pulling into a gas station and being told your car brand isn’t welcome. Strange, right? Yet this is essentially how many EV charging networks operate today. EV drivers don’t care which charge point management system powers their local charging station. They don’t want to know which e-mobility platform handles their app’s backend. They just want to plug in, charge, and go.  

In practice, they often have to juggle multiple charging apps and cards, and spend extensive time searching for compatible charge points. What should be as effortless as filling up a gas tank becomes a puzzle of compatibility. 

The solution isn’t to build more walls, but to increase collaboration. By opening networks through roaming agreements and speaking a common technical language, the e-mobility industry can deliver what EV drivers are actually looking for: seamless charging, anywhere, on any network. 

What is EV charging roaming and why it matters 

Looking back at the gas station model, you don’t need a Shell card for Shell stations and a BP card for BP stations. You just pull up and pay. This is how the combustion engine infrastructure succeeded: through open access, universal compatibility, and no artificial barriers. As the EV charging industry matures, roaming is bringing that same openness to electric mobility.  

EV charging roaming agreements allow charge point operators to open their networks to drivers from other e-mobility service providers. A driver with a charging card from Provider A can charge at stations operated by Provider B, C, and D without downloading new apps or managing multiple accounts. The backend systems handle authentication, pricing, and billing automatically. 

“More players are coming into this industry, and they all need to work together in the end. The goal is to maximise the experience for EV drivers. EV charging is so digitised – it’s not about putting liquid in a car, but about electricity that needs to be tracked across complex grids. That’s why we need to open up and work together, even with competitors. Your customers can charge on my network. It’s win-win. It’s scaling up the whole size of the market.” 

—Inyoung Kang, Propositions Manager at Last Mile Solutions 

This is strategically essential for the industry. When charge point operators treat their networks as exclusive territories limited to only their own customers, they artificially constrain the market. Drivers face limited charging options while operators restrict their own revenue potential. The entire e-mobility ecosystem stays fragmented and frustrating for the end user. 

By connecting networks through roaming, operators expand the effective size of every charging network. Having 1,000 charge points serving only your customers generates less revenue than having 500 charge points accessible to every EV driver in the region. Roaming agreements increase session volume without capital investment in new infrastructure. Your customers get access to thousands more charge points. Partner networks can serve your customers when they travel beyond your coverage area. Everyone benefits from increased utilisation, better driver experiences, and a larger addressable market. 

How charge point management systems communicate using OCPI 

Collaboration can be harder than it sounds, though. Charging networks need to communicate with each other constantly. When a driver plugs in at a charge point operated by Network A using a card from Network B, dozens of data exchanges happen in seconds: authorisation requests, pricing confirmations, session start signals, energy consumption tracking, billing calculations. 

If the networks don’t speak the same technical language, problems arise quickly. In daily life, miscommunication is frustrating. In EV charging management, it’s also expensive. Authorisation delays leave drivers waiting. Billing errors and misapplied VAT mean lost revenue for charge point operators. Data gets lost in translation between incompatible charging management system. 

Sessions that should start instantly get stuck in authentication loops. Energy delivered but not properly logged means revenue is lost. Conversion layers between different protocols slow everything down and add points of failure. And so on. 

Luckily, there is a solution out there. Open protocols like OCPI (Open Charge Point Interface) solve this issue by establishing a common language for EV charging platforms. When systems ‘speak’ OCPI, they exchange data directly and accurately without translation layers, conversion delays, or information lost in transit.  

Roaming agreements and open protocols are turning fragmented networks into collaborative infrastructure. This benefits all industry stakeholders: better experiences for drivers, higher utilisation for operators, and faster growth for the entire e-mobility ecosystem. OCPI is now the European standard for roaming communication, supported by major industry organizations like ChargeUp Europe and implemented by leading CPMS platforms across the continent.  

Building Europe’s largest roaming network 

At Last Mile Solutions, we operate one of Europe’s largest roaming networks, connecting over 1 million charge points across multiple countries and making them accessible to drivers regardless of which e-mobility service provider they use. This means that all our partners can also promise their drivers access to over 1 million charge points. 

We are leading contributors to industry organisations like the EVRoaming Foundation and eViolin, helping advance open standards and interoperability across the e-mobility ecosystem. Our leadership team actively contributes to setting the technical standards that are shaping the future of EV charging infrastructure in Europe. 

Managing one of the continent’s most connected charging networks gives us a unique perspective on what works in roaming implementations. We handle billing across diverse networks, manage authentication for thousands of daily sessions, and maintain the operational infrastructure that keeps cross-network charging running smoothly.  

Ready to expand your charging network with roaming? Our CPMS platform connects you to Europe’s largest roaming ecosystem.