OCPP Protocol Explained: Why Open Standards Matter for EV Charging

If you've spent any time researching EV charging infrastructure, you've probably seen "OCPP" mentioned in technical specifications and marketing materials. It's one of those acronyms that gets thrown around constantly in the industry, often without proper explanation.

So what exactly is OCPP, and why should you care?

The short answer: OCPP (Open Charge Point Protocol) is the communication standard that enables EV chargers from different manufacturers to communicate with different charging management systems. Think of it as the universal language of EV charging.

The longer answer involves understanding why this matters for anyone investing in charging infrastructure, using public charging networks, or planning for the future of electric mobility.

This guide explains what OCPP actually does, why open standards matter more than you might think, and how this technical detail affects your real-world charging experience.

What Is OCPP? The Basics

OCPP stands for Open Charge Point Protocol. It's a communications protocol, essentially a set of rules, that defines how charging stations communicate with central management systems.

The problem OCPP solves

Without a standard protocol, every charger manufacturer would create their own proprietary communication system. You'd end up with charging stations that work only with specific management platforms, creating a fragmented ecosystem where hardware and software choices are permanently locked together.

This scenario isn't hypothetical. It's precisely what happened in other industries before open standards emerged. Early mobile networks, for instance, suffered from incompatibility issues until common standards developed.

How OCPP works

The protocol sits between two main components:

• The charging station (the physical hardware you plug your car into)
• The charging management system (the backend software that controls access, monitoring, and operations)

OCPP defines the messages exchanged between these two components, including:

• Starting and stopping charging sessions
• Monitoring energy consumption in real time
• Managing user authentication and authorisation
• Reporting faults and diagnostics
• Handling firmware updates
• Managing reservations
• Controlling charging profiles for load management

Because OCPP is an open standard, freely available for anyone to implement, manufacturers and network operators can build compatible systems without licensing proprietary technology or getting locked into specific vendors.

It's worth noting what OCPP doesn't do: payment processing happens through separate external systems. OCPP handles the authorisation check (confirming a user can charge), but the actual credit card transaction occurs through dedicated payment hosts outside the protocol. For more on how payment works at EV charging stations, see our guide on apps, contactless, and RFID payment options.

Why "Open" Standards Matter

The "open" part of Open Charge Point Protocol deserves emphasis. This isn't just a headline; it has real practical implications.

Vendor independence

When charging infrastructure uses OCPP, the hardware manufacturer and the software platform operator don't need to be the same company. You can install chargers from one supplier and manage them through a completely different management system.

This matters because you're not locked into a single vendor's ecosystem. If your management platform provider increases prices dramatically, provides poor service, or goes out of business, you can switch to a different platform without replacing your physical hardware.

Let's say you install 50 charging points using a proprietary system. If that vendor decides to increase their monthly fees by 200% or discontinues support for your hardware, you're stuck. Your only option is to replace all your charging infrastructure, potentially wasting hundreds of thousands of pounds.

With OCPP-compliant infrastructure, you switch management platforms. The hardware stays exactly where it is.

Future-proofing investments

EV charging infrastructure represents a significant capital investment. Charging stations should remain operational for 10+ years. The management systems and business models around charging, however, will evolve considerably over that period.

Open standards mean your hardware investment remains relevant even as software capabilities advance and business requirements change.

Innovation and competition

When protocols are open, more companies can enter the market. This drives innovation: new management platforms can emerge offering better features, lower costs, or specialised functionality without needing to manufacture their own hardware.

Competition benefits everyone. Prices stay reasonable. Service quality improves. Features evolve faster.

Proprietary systems, by contrast, create natural monopolies. Once you've invested in hardware, the platform provider knows you're captive. There's no competitive pressure to improve.

OCPP Versions: What's the Difference?

OCPP has evolved through several versions since its origins in 2009. Understanding the differences helps when evaluating charging infrastructure.

Version timeline

Development of the protocol began in 2009 by ElaadNL in the Netherlands. In late 2024, OCPP 2.0.1 Edition 3 was approved as international standard IEC 63584, marking a significant milestone for the protocol's recognition and adoption.

OCPP 1.6

Released in 2015, OCPP 1.6 remains the most widely implemented version globally. The Open Charge Alliance confirms it is "now widely implemented by CS and CSMS manufacturers around the world," and industry analysis suggests an overwhelming majority of public and commercial EV charging stations run on OCPP 1.6. It's proven, stable, and handles the core functions of charging station management effectively.

What OCPP 1.6 does well:

1. Remote start and stop of charging sessions through dedicated messages in the Core Profile
2. Real-time monitoring via status notifications covering nine different charge point states
3. User authentication using an authorisation system with ID tags
4. Local authorisation lists that allow charging to continue even when internet connectivity drops
5. Smart charging capabilities including setting charging profiles and load balancing
6. Comprehensive firmware management covering updates, diagnostics, and fault reporting

For most public and workplace charging deployments, OCPP 1.6 provides everything needed. It's why Zest's infrastructure is built on this standard: it delivers reliable functionality that's been tested extensively across deployments in over 137 countries.

Limitations:

• Smart charging uses static, predefined profiles rather than dynamic real-time adjustments
• No native integration with external energy management systems for real-time grid interaction
• Vehicle-to-grid capabilities aren't supported (unidirectional charging only)
• No native support for tariff or pricing information
• Uses older SOAP/XML communication standards alongside JSON/WebSocket

OCPP 2.0.1

OCPP 2.0 was released in April 2018, introducing significant architectural changes. OCPP 2.0.1 followed in March 2020, incorporating bug fixes discovered during implementations of the original 2.0 specification.

Key improvements:

• Better smart charging: Much more sophisticated load management capabilities, including a dedicated ISO 15118 Certificate Management functional block enabling "plug and charge" functionality
• Enhanced security: Three security profiles with mandatory TLS encryption, certificate-based mutual authentication, and signed firmware updates
• Improved efficiency: Uses JSON exclusively over WebSocket, with persistent connections eliminating NAT traversal issues
• Native tariff support: Built-in support for communicating pricing and cost information
• Device management: Better tools for managing large networks of chargers

Why is OCPP 2.0.1 adoption slower?

Despite being available since 2020, OCPP 2.0.1 adoption remains limited compared to 1.6 for several reasons:

• The specification is considerably more complex, requiring more development effort
• When the certification programme launched in June 2023, only 11 companies received initial certification
• Many advanced features aren't yet essential for most deployments
• The existing installed base runs on 1.6, and OCPP 2.0.1 isn't backward compatible
• Vehicle support for advanced features like ISO 15118 plug-and-charge remains limited

This is changing. The US NEVI programme, backed by $5 billion in federal funding, requires OCPP 2.0.1 compliance by 2025 for federally funded stations, driving accelerated adoption.

OCPP 2.1

The latest version, released in January 2025, adds:

• Dedicated Bidirectional Charging Functional Block for V2G and V2X support
• Native ISO 15118-20 integration for bidirectional power transfer
• Distributed energy resources control for grid integration
• Local cost calculation capabilities

OCPP 2.1 is backwards compatible with OCPP 2.0.1, making migration straightforward for operators already on that platform.

What OCPP Means for Different Users

The benefits of OCPP vary depending on your relationship with the charging infrastructure.

For Site Hosts and Infrastructure Investors

If you're a business installing charging infrastructure, whether for customers, employees, or commercial operations, OCPP protects your investment. Whether you're in hospitality, retail, or commercial real estate, the underlying principle remains the same.

Key benefits for site hosts:

For EV Drivers

As a driver, OCPP operates mainly in the background. You won't interact with it directly. But it affects your charging experience in meaningful ways. If you're new to public charging, our first-timer's guide to using EV charging stations covers the practical basics.

Network compatibility: OCPP enables roaming agreements between networks. This means services like Octopus Electroverse can provide access to multiple charging networks through a single account.

Better user experience: Competition between management platforms drives better apps, more transparent pricing, and improved customer service.

Future capabilities: Advanced features like plug-and-charge depend on protocols like OCPP working with vehicle communication standards.

For Charging Network Operators

For companies running charging networks, OCPP provides essential operational benefits:

• Select the best charging hardware for each location without compatibility concerns
• Manage chargers from multiple manufacturers through one platform
• Enable smart charging capabilities essential for grid load management

The Real-World Impact of Open Standards

The difference between open and proprietary systems becomes most apparent when things go wrong or requirements change.

The Enel X shutdown: A cautionary tale

In October 2024, Enel X Way North America announced it was closing its EV charging business with just nine days' notice. The company had operated approximately 125,000 chargers, and the sudden shutdown left thousands of customers scrambling.

The impact varied dramatically based on whether infrastructure used open standards. Commercial JuiceBox chargers that relied on Enel's proprietary software and weren't OCPP-compliant became non-functional, forcing owners into costly hardware replacements or expensive migration services. Those with OCPP-compliant infrastructure had options: they could switch to alternative management platforms and keep their hardware operational.

Industry failures: A pattern emerges

Each case demonstrates the same lesson: when infrastructure depends entirely on a single vendor's continued operation, business failures or strategic pivots can render perfectly functional hardware worthless.

OCPP at Zest: Why We Built on Open Standards

Zest's charging infrastructure is built on OCPP 1.6. This decision reflects our fundamental approach to EV charging: long-term thinking focused on creating infrastructure that serves users well beyond the typical planning horizon.

Why OCPP 1.6 specifically

We chose OCPP 1.6 because it's proven, widely supported, and delivers all the functionality needed for reliable public charging today. The protocol has been deployed across over 137 countries through more than 400 Open Charge Alliance member organisations.

The features in OCPP 2.0.1 and 2.1, whilst interesting from a technical perspective, don't yet provide compelling advantages for most public charging operations. When vehicle support for advanced features becomes widespread and the grid integration benefits become more valuable, we'll evaluate migration.

What this means for our partners

Site hosts working with Zest benefit from the vendor independence that OCPP provides. The infrastructure we install remains flexible. If a future management platform offers revolutionary features or significantly better economics, the hardware we've deployed can take advantage of it.

Integration with roaming platforms

Our OCPP infrastructure integrates seamlessly with roaming services like Octopus Electroverse. Drivers can access Zest chargers through multiple platforms, using their preferred payment methods, whether that's our app, contactless payment, or RFID cards.

The Future of EV Charging Standards

OCPP continues evolving. Understanding where the protocol is heading helps with long-term infrastructure planning.

Key developments to watch

1. International standardisation: OCPP 2.0.1 Edition 3 approval as IEC 63584 signals growing institutional recognition
2. Vehicle-to-grid (V2G): OCPP 2.1's Bidirectional Charging Functional Block enables full V2G support
3. Enhanced security: Mandatory TLS encryption and certificate-based authentication in newer versions
4. Plug-and-charge: ISO 15118 integration enabling automatic authentication and payment

Timeline for adoption

The transition to newer OCPP versions will take years, not months. Key factors include:

• NEVI programme driving US adoption of OCPP 2.0.1 by 2025
• Vehicle manufacturers slowly adding ISO 15118 support
• Grid integration requirements becoming more demanding
• Existing 1.6 infrastructure remaining functional and effective

Making Decisions About Charging Infrastructure

If you're evaluating charging infrastructure options, OCPP compliance should be non-negotiable.

Essential questions to ask

1. Is the hardware OCPP-compliant? (If not mentioned, assume it isn't)
2. Which OCPP version is supported?
3. Can you switch management platforms without hardware replacement?
4. What's the total cost of ownership over 10 years?
5. What happens if the vendor exits the market?

Beyond the protocol

OCPP handles communication between chargers and management systems. That's essential. But it's not the only thing that matters:

• Hardware reliability: Physical durability, weatherproofing, component quality
• Management platform capabilities: User apps, pricing transparency, customer support
• Installation quality: Electrical work, civil works, site layout
• User experience: Payment flexibility, roaming support, accessibility

Understanding how EV charging works and connector types can help you make better infrastructure decisions.

The Bottom Line on Open Standards

OCPP matters because it protects investments, enables competition, and creates flexibility.

• For site hosts and infrastructure investors, it's the difference between a capital investment that remains useful for 10+ years and one that becomes obsolete when vendors change strategy or go out of business.
• For network operators, it means operational flexibility: choosing the best hardware for each location and the best management platform for your requirements without worrying about compatibility.
• For drivers, it enables seamless roaming and a better user experience driven by genuine competition between service providers.

The EV charging industry is still young. Business models are evolving. Technology capabilities are advancing rapidly. Regulatory requirements continue to develop. Building infrastructure on open standards means you're prepared for change rather than locked into today's assumptions.

That's not exciting or revolutionary. It's just sensible long-term thinking. Which is precisely what charging infrastructure requires.

‍

‍