Learn what roaming hubs are, and how they simplify EV charging across networks.

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

If you’ve ever driven your electric vehicle beyond your home network, maybe on a weekend trip or across the border, you’ve probably noticed how charging can suddenly become complicated. One app works at home, but not abroad. One charging station needs a different RFID card. It’s not always seamless.

Roaming hubs help simplify this messy experience by connecting charging networks behind the scenes. They make it possible for EV drivers to plug in and charge without needing a new app or contract for every provider. And for businesses in the 

, they reduce the technical and commercial hassle of managing dozens of separate roaming agreements.

In this article, we’ll break down what roaming hubs are, how they work, and why they’re becoming essential for a more connected, user-friendly EV charging experience.

to dive deeper into the technical and strategic side of eRoaming.

A roaming hub is a digital platform that connects different 

, making it easier for them to communicate and share access with one another.

Instead of building and maintaining one-to-one (bilateral) connections between every 

, a roaming hub acts as a central connector where multiple players plug in once and automatically become interoperable with others on the network.

 connects to a roaming hub → they become accessible to many eMSPs.

 connects to the same hub → their users can access a wide network of charging stations.

This setup drastically reduces the effort and cost of creating separate agreements with every partner. It also accelerates market growth by enabling broader access and smoother user experiences.

What are the key functions of a roaming hub?

It facilitates the authentication and authorization of EV drivers

It handles charging session data exchange (start/stop times, energy consumed, location, etc.)

It supports billing and settlement between networks

It’s often built on standard protocols like 

How roaming hubs fit into the eRoaming ecosystem

To understand the role of roaming hubs, it's helpful to zoom out and look at the bigger picture: the eRoaming ecosystem.

 lets EV drivers use charging stations from different networks without signing up for a new app or contract each time. It allows drivers to charge across countries and providers as if everything were part of one big network.

In short, it makes charging your EV on the go, especially across borders, 

There are two main ways this interoperability is achieved:

Direct agreements between two companies (e.g., CPO ↔ eMSP)

Requires custom integration for each new partner

Scales poorly as the number of partners grows

Each new connection automatically links to all others on the hub

More scalable, efficient, and easier to manage

The EV ecosystem is expanding fast, and so is the number of CPOs and eMSPs. Roaming hubs help untangle the web of partnerships by offering a scalable, interoperable foundatio

Instead of juggling dozens of integrations, businesses can focus on improving the charging experience, while the hub handles the connectivity.

Roaming hubs are a critical enabler of smoother EV charging experiences and faster market expansion. Here's how they add value to each part of the EV ecosystem:

For charge point operators: Faster market reach

 By connecting to a roaming hub, CPOs make their stations available to dozens (or hundreds) of eMSPs at once.

 No need to build and maintain one-to-one connections.

 Hubs often standardize session data and settlements.

 A small regional CPO plugs into a roaming hub and instantly becomes visible to international drivers using major 

For eMobility service providers: Competitive advantage

 Offer customers access to more chargers without building new partnerships one by one.

 Less friction = more charging confidence = stronger user retention.

 Launch in new markets without the need for local agreements in place first.

 An eMSP can expand its app’s coverage overnight by connecting to a hub already populated with hundreds of CPOs.

 No need to juggle multiple accounts or RFID cards.

 Roaming hubs make it easier to charge across different countries and networks.

 Better network reach means fewer dead zones and more confidence on the road.

 A driver from Germany using one eMSP app can charge in France or the Netherlands through a roaming hub connection, without switching providers.

 Common protocols and standards reduce technical friction.

While roaming hubs offer major advantages in scalability and convenience, they’re not without their technical, commercial, and operational hurdles. Understanding these challenges is key to making informed decisions about joining or integrating with a hub.

1. Protocol compatibility and technical complexity

Most roaming hubs rely on standard communication protocols, like 

Not all CPOs and eMSPs are using the same protocol versions.

Custom implementations can lead to compatibility issues

Initial integration can require heavy technical effort, especially for companies with legacy systems.

Choosing a hub that supports open, well-documented, and actively maintained protocols reduces the long-term burden.

Roaming hubs depend on clean, consistent, and real-time data to deliver a seamless experience. However:

Incorrect location or pricing data can frustrate drivers.

Session start/stop errors create billing disputes.

🚨Poor data leads to broken user experiences even when the underlying network is strong.

3. Commercial agreements and transparency

Each roaming hub operates with its own business model. Key pain points include:

Lack of pricing transparency for charging sessions.

Limited control over how stations are listed or prioritized in partner apps.

🚨Evaluate not just the technical features of a hub, but also its commercial model and how it aligns with your business goals.

4. Vendor lock-in and limited flexibility

Some hubs operate with closed ecosystems or require long-term commercial commitments.

Switching hubs can be difficult once deeply integrated.

It may be hard to interconnect with networks 

🚨Make sure the hub you choose doesn’t limit your future interoperability or strategic growth options.

5. Fragmentation in the roaming landscape

Despite their promise of unification, the roaming hub space itself is fragmented. With multiple major hubs (e.g., 

, Gireve, e-clearing.net), businesses often have to:

Connect to multiple hubs to achieve full coverage

🚨Some companies use hub-to-hub interconnections to extend reach, but this introduces new layers of complexity.

Understanding these trade-offs helps you weigh scalability against control and reliability, and prepare for smoother integrations.

Types of roaming hubs: What’s out there and how they differ

Not all roaming hubs are built the same. Depending on their structure, business model, and level of openness, the experience and value can vary significantly for CPOs, eMSPs, and even end users.

Here’s how to navigate the key categories:

Operated by independent entities with no direct stake in charging or mobility services.

Aim to create a level playing field for all market participants.

Focus on transparency, interoperability, and open standards.

 – non-profit foundation, protocol-agnostic, governance-driven.

Operated by for-profit companies, sometimes backed by major automotive or energy players.

May offer premium services, tighter integrations, or bundled offerings with their platforms.

Learn what roaming hubs are, how they simplify EV charging across networks, and how Solidstudio helps CPOs & eMSPs integrate with them.

A Practical Guide to Roaming Hubs in EV Charging Networks

Check out the new series of articles about the software migration in the EV charging business.

After founding Solidstudio, Pawel was an originator in terms of pursuing expertise in eMobility. With the build-up of a solid knowledge-base on industry’s needs & wants, he now keeps a close eye on products’ development. He’s also hugely responsible for the business’ side and designs the business models for our products.

Paweł Małkowiak

For those interested in the topic of software migration (both Charge Point Operators and eMobility Service Providers), we have published a comprehensive ebook combining all the knowledge, including the business and strategic aspects. 

Platform Migration for EV Charging Businesses

, this installment shifts focus from the 

In previous articles, we explored the strategic reasons behind software migration and what to consider when switching platforms. Now, we’ll guide you through the 

practical steps involved in migrating charging networks

From evaluating new software to planning the migration method and testing for OCPP compliance, this post outlines a complete process. Plus, you’ll find a 

free downloadable OCPP Acceptance Testing checklist

 to help ensure your chargers integrate smoothly with the new system.

1. Assess and evaluate the new EV charging software

Before migrating, it’s crucial to thoroughly assess whether the new software meets the technical and operational needs of your charging network.

Ensure it supports your current setup and offers enhanced features or scalability. Focus on compatibility with your specific station models, network requirements, and 

This early evaluation helps reduce risks, avoid future rework, and gain a competitive edge by selecting the most robust and future-ready platform.

2. Confirm charger compatibility and integration via OCPP testing

Make sure the new software fully supports every charging station in your network. This is critical for avoiding service disruptions post-migration.

Conduct OCPP acceptance testing to validate that all stations communicate properly with the new backend. This step helps uncover compatibility issues early, before they impact your operations.

 (PDF) from the box on the left side of this page.

Before migrating chargers, start by aligning the structural setup of both the old and new systems. This includes:

Replicating or improving the structure in the new software ensures functional continuity and avoids disruptions.

A detailed understanding of both ecosystems will help you maintain operational stability throughout the migration process and beyond.

4. Choose the right migration method for charging stations

After defining the software structure, determine how you’ll migrate each charging station to the new system.

 that defines how it connects to the backend. Based on this setup, you’ll need to decide between:

, where configuration updates are pushed over the network

, requiring physical access to the charger

Select the most efficient method based on your infrastructure and resources. A well-planned approach minimizes service interruptions during the transition.

 remotely migrated 9,000 charge points without any downtime. Read how they did it in our case study.

If your network includes many charging stations, a 

Start with a small group of chargers in a controlled environment. Test their performance with the new backend and confirm everything works as expected.

Once validated, gradually migrate additional stations in batches—using a specific identifier or key. This step-by-step process helps:

This method reduces operational risk and ensures a smooth transition at scale.

6. Migrate OCPI connections for interoperability

An essential part of the migration process is transferring your 

 (Open Charge Point Interface) connections

These connections enable real-time communication between your charging platform and external partners, like roaming networks, eMSPs, and backends. Ensuring a seamless handover protects 

What's next in your EV software migration journey?

Successfully migrating your EV charging network to a new software system demands more than just flipping a switch. It requires structured planning, technical validation, and phased execution, from evaluating the new platform to ensuring OCPP and OCPI compliance.

Whether you're a CPO or eMSP, using proven processes and checklists will save time, reduce downtime, and protect your business operations.

 Our team is here to help you ensure a smooth and scalable transition.

Learn the EV charger software migration process and download a free OCPP acceptance testing checklist to ensure seamless system integration.

EV Charging Platform Migration: Key Steps & Testing

Two actively supported independent open standards for EV roaming.

EV roaming and its open protocols, like OCPI and OCHP, are helping solve one of the most persistent challenges in 

For many EV drivers, especially when traveling across networks or borders, charging isn't as seamless as it should be. Multiple apps, incompatible systems, and limited network access can get in the way.

This article explores how protocols such as OCPI and OCHP support interoperability, simplify cross-network charging, and enable a more connected EV charging infrastructure.

EV roaming enables electric vehicle drivers to access charging stations outside their primary eMobility Service Provider (eMSP) network. In practice, this means a driver can use a charger operated by a different Charge Point Operator (CPO) without needing a new account, additional app, or separate authentication process.

Behind this convenience is a framework of technical standards and roaming agreements that facilitate real-time data exchange. When a session begins, the driver’s credentials are verified, often through an open EV charging protocol like OCPI or OCHP. Once authorized, data such as session duration, energy usage, and pricing is exchanged between the CPO and eMSP, ensuring proper billing and transparency.

This interoperability reduces friction for drivers, allowing access to a broader 

 without the barriers of closed ecosystems. It simplifies the charging experience, encourages broader EV adoption, and supports more efficient use of existing infrastructure. For operators, roaming expands reach, increases station utilization, and aligns with growing expectations for EV charging interoperability.

Why is roaming essential for EV infrastructure?

As electric mobility gains momentum, so do the expectations of EV drivers. A consistent, reliable charging experience regardless of location or network is becoming essential. Without roaming, users are often restricted to closed ecosystems tied to a single eMSP. This limitation becomes especially problematic when crossing city, regional, or national boundaries, where incompatible systems can hinder access.

EV roaming addresses these gaps by enabling interoperability across networks. Through protocols like OCPI and OCHP, drivers can initiate sessions on unfamiliar networks without interruption, simplifying access and reducing range anxiety.

The benefits extend beyond user convenience. For Charge Point Operators (CPOs), roaming increases charger utilization and visibility without the overhead of onboarding every new user. For eMSPs, it enhances platform value by offering a wider, more accessible network, helping build loyalty and trust.

Additionally, roaming supports regulatory compliance. Many public infrastructure policies now require open access and multi-provider support. Roaming ensures these mandates can be met technically and operationally.

In essence, roaming transforms EV charging from a fragmented landscape into a connected ecosystem, supporting user experience and network scalability.

EV roaming relies on secure and standardized communication between different systems, allowing EV drivers to access charging stations beyond their primary provider’s network, without added complexity.

This process involves multiple parties: the driver, their eMSP, the CPO, and sometimes a central 

. These actors exchange data using open EV charging protocols like OCPI or OCHP to coordinate identity verification, session authorization, real-time pricing, and billing.

: The driver initiates charging via an RFID card or app provided by their eMSP.

: The CPO checks whether the user is valid, either directly with the eMSP or via a roaming hub.

: Once approved, the session begins. Data about usage, tariff, and duration is tracked.

: At the end of the session, the CPO sends a Charge Detail Record (CDR) to the eMSP for reconciliation.

This exchange must happen quickly, accurately, and securely. In hub-based models, a platform like e-clearing.net handles routing and validation. In peer-to-peer setups, enabled by OCPI, data flows directly between systems. Some networks also blend both approaches to meet varying regional or commercial needs.

The key outcome? The technical complexity is hidden from the driver. They simply charge, no matter whose infrastructure they’re using.

The Open Charge Point Interface (OCPI) is a widely adopted open protocol that enables seamless, 

. Developed by eViolin and now maintained by the EVRoaming Foundation, OCPI enables direct communication between eMobility Service Providers (eMSPs) and Charge Point Operators (CPOs) without relying on a central intermediary.

Designed for flexibility and scalability, OCPI supports a decentralized model where providers can establish and manage bilateral roaming partnerships on their terms. This approach offers commercial freedom, data ownership, and greater control over integration architecture.

Key capabilities of the OCPI protocol include:

 of drivers using real-time checks or static whitelists.

, including Charge Detail Records (CDRs), to support accurate billing and reporting.

, enabling pre-session access to tariff and location-specific cost details.

, such as charger availability and power output.

 support dynamic control based on user preferences or grid demand.

OCPI is built on a RESTful API structure using JSON, making it accessible for modern development teams. Its modular design allows companies to implement specific features based on user needs, streamlining adoption without overengineering.

In practice, OCPI has seen widespread use across Europe, including the Netherlands, Germany, Poland, and France, and continues to expand into global markets. It also supports regulatory requirements such as Germany’s Eichrecht law, which mandates secure and auditable metering data.

For organizations seeking an open EV charging protocol that supports interoperability, customization, and cross-border scalability, OCPI is a proven and future-ready solution.

OCHP and OCHPDirect: Roaming through a central hub

While OCPI enables direct, decentralized roaming, the Open Clearing House Protocol (OCHP) supports a centralized approach to EV roaming, one that prioritizes simplicity, stability, and streamlined integration.

Smartlab Innovationsgesellschaft and ElaadNL develop OCHP, and it underpins platforms like e-clearing.net, a neutral roaming hub that facilitates data exchange between Charge Point Operators (CPOs), eMobility Service Providers (eMSPs), and even Navigation Service Providers (NSPs).

Unlike peer-to-peer models, OCHP allows each party to connect once to the hub, which routes data, manages authorizations, and forwards billing records. This “connect once, reach many” model significantly reduces the onboarding burden for new participants.

Technical and operational features of the OCHP protocol:

 supporting asynchronous data transfer and batch processing.

 ensures that charging sessions can proceed even during temporary network or hub outages.

Central handling of Charge Detail Records (CDRs)

 for session validation and billing reconciliation.

Exchange of pricing, charger availability, and location data

To enable more dynamic interactions, OCHPDirect extends the base protocol with support for real-time data flows. This includes capabilities such as remote session control, smart charging adjustments, and live metering, while still leveraging the underlying hub structure.

This combination offers the best of both worlds: the structured coordination of a central hub with the agility of selective direct integrations. It’s particularly valuable for public sector projects, smaller operators, or national-scale programs looking for efficient ways to scale roaming capabilities.

For providers focused on governance, policy alignment, and ease of integration, OCHP represents a practical and robust foundation for EV roaming.

OCPI and OCHP both serve the same overarching purpose—enabling EV roaming between 

—but they differ significantly in how they approach integration, communication, and scalability.

OCPI is based on a peer-to-peer model. It allows eMSPs and CPOs to connect directly without a central intermediary. This approach gives operators more control over commercial agreements, data handling, and feature implementation. It’s built using RESTful APIs and JSON, supporting real-time, modular communication. This makes it ideal for flexible and scalable roaming setups where rapid innovation or bespoke partnerships are a priority.

OCHP, by contrast, is built on a centralized hub-and-spoke model. All participants connect once to a central platform, typically 

, which facilitates communication. OCHP uses SOAP-based messaging and focuses on asynchronous, batch-style data exchange. This model simplifies onboarding and is particularly effective for standardized, policy-driven infrastructure, such as national EV programs or municipal tenders.

OCHPDirect, an extension of OCHP, enables real-time data exchange within a hub-based setup. It allows operators to implement features like remote session control and smart charging without giving up the centralized integration model.

OCPI offers flexibility and customization, making it suitable for fast-moving commercial platforms. OCHP provides structure and ease of integration, ideal for public sector and regulatory-driven environments. Many networks choose to support both, combining the scale and simplicity of OCHP with the agility of OCPI to meet diverse operational needs.

The growth of EV roaming is not only driven by market demand and technological innovation, but it’s increasingly being shaped by regulation. Across Europe and beyond, governments are setting clear requirements for interoperability, making roaming capabilities a condition for public infrastructure deployment.

The rationale is simple: a fragmented charging ecosystem limits access, slows adoption, and undermines sustainability goals. To address this, policies are emerging that mandate open access and enforce compliance with recognized roaming standards like OCPI and OCHP.

Take Slovakia, for example. New public charging points must connect to a roaming platform that provides access to at least 80 operators, within just three months of commissioning. This ensures national-scale interoperability from the start.

In Germany, cities like Berlin require public CPOs to register with centralized platforms for user authentication. This guarantees fair and open access, regardless of which eMobility Service Provider a driver uses, while improving regulatory oversight.

Oslo has embedded openness into its infrastructure contracts. The city mandates that data on pricing, charger availability, and access be made available to third parties, promoting innovation in EV services, navigation, and urban mobility planning.

These are not isolated measures. They reflect a broader trend toward standardization and compliance, aligned with the European Union’s Green Deal and 2050 climate targets. Interoperability, once a technical preference, is now becoming a legal and operational requirement.

Protocols like OCPI and OCHP provide the technical foundation for meeting these expectations. They support seamless data exchange, identity verification, session tracking, and billing transparency, ensuring that roaming networks meet both business needs and regulatory standards.

Building a roaming-ready EV network: What you need to know

As EV adoption accelerates and regulatory expectations evolve, the need for a roaming-ready infrastructure has shifted from optional to essential. Whether you're a CPO, an eMSP, or a platform developer, supporting EV roaming is now a baseline requirement for participation in modern electric mobility ecosystems.

, enabling roaming means greater visibility and increased utilization of charging assets. By making stations accessible to a wider pool of drivers—regardless of their eMSP—you improve return on investment and enhance your position in public or competitive tenders. Protocols like OCPI allow you to form direct partnerships with service providers, while OCHP provides a fast track to scale through established hub networks.

, roaming is about delivering a seamless, trustworthy charging experience. Your users expect to charge their vehicles without friction, even when they cross a city, region, or national border. Integrating roaming through OCPI offers flexibility to tailor commercial agreements and user flows, while OCHP ensures quick access to a broad charging footprint via hub connectivity.

platform developers and software providers

, roaming support should be built into the architecture from day one. Your clients need modular, scalable, and protocol-ready systems, capable of handling integrations across OCPI, OCHP, and evolving standards. A future-proof platform enables faster go-to-market, easier compliance, and adaptability across regions and use cases.

Across the board, the key message is clear: it’s not about whether to support roaming, but how well and quickly it can be implemented. Operators that embrace roaming will be better positioned to meet regulatory benchmarks, serve a growing user base, and scale sustainably in an increasingly competitive market.

Building for scale: Why interoperability is the future of EV charging

EV roaming is no longer a nice-to-have feature—it’s a core component of modern charging infrastructure. Whether enabled through the flexibility of OCPI or the streamlined approach of OCHP, open protocols are what make seamless, interoperable charging possible. They provide the technical and commercial foundation for scaling networks, improving driver experience, and complying with growing regulatory requirements.

For Charge Point Operators, roaming expands your customer base and enhances infrastructure efficiency. For eMobility Service Providers, it strengthens your value proposition by offering consistent, cross-network access. And for platform builders, it’s a must-have capability that ensures long-term adaptability.

Learn how OCPI and OCHP protocols enable seamless EV roaming, promote interoperability, and support scalable open charging networks across Europe and beyond.

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