🔌 OCPP Client

A lightweight, embedded-friendly Rust OCPP communication framework for building real charge points and CSMS integrations.

🚀 Overview

OCPP Client is the communication layer of the Flowion Rust OCPP ecosystem, providing the networking and transport foundation required to build OCPP-enabled charge points and backend integrations.

The library handles the complexities of establishing and managing OCPP connections, including:

Connection lifecycle management
Transport handling
Message routing
Communication reliability

OCPP message types and protocol definitions are provided by ocpp-types, while OCPP Client focuses on the communication layer required to exchange messages between charge points and Charge Station Management Systems (CSMS).

Designed for both cloud/server environments and resource-constrained embedded systems, OCPP Client supports standard WebSocket connections as well as no_std compatible transports for STM32-based platforms.

The library currently supports OCPP 1.6J, OCPP 2.0.1, and OCPP 2.1.

✨ Features

🦀 Native Rust implementation
🔌 OCPP communication layer
⚡ OCPP 1.6J support
🚀 OCPP 2.0.1 support
⚡ OCPP 2.1 support
🌐 WebSocket transport
🔒 Secure WebSocket (WSS)
🔋 STM32-compatible transport layer
🔄 Connection lifecycle management
📨 Message routing
🧩 Transport abstraction
🪶 Lightweight runtime
💾 no_std support for embedded environments
🖥️ std support enabled by default for desktop and server applications

🔌 Supported Protocols

Protocol	Status
OCPP 1.6J	✅ Supported
OCPP 2.0.1	✅ Supported
OCPP 2.1	✅ Supported

🌐 Supported Transports

Transport	Status
WebSocket	✅ Supported
Secure WebSocket (WSS)	✅ Supported
STM32 transport	✅ Supported

⚙️ Feature Flags

OCPP Client supports both standard Rust environments and embedded systems.

By default, the std feature is enabled:

[dependencies]
ocpp-client = "0.x"

For embedded targets or no_std environments:

[dependencies]
ocpp-client = { version = "0.x", default-features = false }

This allows the same OCPP communication foundation to run on resource-constrained devices such as STM32 microcontrollers while still supporting traditional server-side applications.

🏗️ Architecture

OCPP Client separates protocol definitions from communication.

┌────────────────────────────────────────────┐
│          Your Application                  │
│          Charge Point / CSMS Logic         │
└──────────────────────┬─────────────────────┘
                       │
                       │
┌──────────────────────▼─────────────────────┐
│              ocpp-charge-point             │
│                                            │
│  Complete charge point firmware framework  │
│  Add hardware bindings and deploy          │
└──────────────────────┬─────────────────────┘
                       │
                       │
┌──────────────────────▼─────────────────────┐
│              ocpp-client                   │
│                                            │
│  OCPP communication runtime                │
│  Transport abstraction                     │
│  WebSocket / embedded transports           │
└──────────────────────┬─────────────────────┘
                       │
                       │
┌──────────────────────▼─────────────────────┐
│               ocpp-types                   │
│                                            │
│  OCPP message types                        │
│  Protocol models                            │
│  Serialization                              │
└────────────────────────────────────────────┘

🌐 Flowion OCPP Ecosystem

OCPP Client is designed as a modular building block within the Flowion Rust OCPP ecosystem.

Each project has a focused responsibility, allowing developers to choose the right level of abstraction for their application.

📦 ocpp-types

OCPP protocol definitions and data models

ocpp-types provides the foundation for working with OCPP messages in Rust.

It contains:

OCPP message types
Protocol models
Serialization and deserialization
Version-specific protocol definitions

OCPP Client builds on top of ocpp-types to provide communication capabilities.

🔌 ocpp-client

OCPP communication and transport layer

This repository provides the runtime required to connect OCPP-enabled systems.

It handles:

Connection management
Transport abstraction
Message routing
WebSocket communication
Embedded-compatible transports
no_std environments

It is designed to run in both:

🖥️ Server environments
🔋 Embedded charge point environments

⚡ ocpp-charge-point

Complete charge point firmware framework

ocpp-charge-point provides a complete framework for building OCPP-enabled charge point firmware.

The goal is to make developing custom charging hardware as simple as implementing the required hardware bindings.

Developers provide hardware-specific implementations such as:

GPIO control
Contactor control
Metering interfaces
Connector handling
LEDs and user interfaces
Hardware drivers

while the framework handles:

Charge point state management
OCPP communication
Charging workflows
Backend communication
Protocol integration

This allows manufacturers and developers to build custom OCPP-compatible chargers without implementing the complete protocol stack from scratch.

🎯 Use Cases

OCPP Client can be used for:

🚗 Building EV charge point firmware
🏭 Developing OCPP-enabled hardware
🖥️ Building CSMS integrations
🧪 Testing OCPP implementations
🔋 Connecting embedded devices to charging platforms
⚡ Creating custom charging solutions
🤖 Automated integration testing

📦 Installation

Add the dependency to your Cargo.toml:

[dependencies]
ocpp-client = "0.x"

🚀 Quick Example

use ocpp_client::Client;

#[tokio::main]
async fn main() {
    let client = Client::new();

    client
        .connect("wss://example.com/ocpp")
        .await
        .unwrap();
}

🧪 Testing

OCPP Client is designed for:

Integration testing
Charge point development
Embedded testing
CSMS validation
Automated test environments

It can be combined with simulators and real charging hardware to validate complete OCPP workflows.

🛣️ Roadmap

Planned improvements:

🔌 Additional embedded transports
📚 More examples
🧪 Expanded integration tests
🔧 Improved developer tooling

🤝 Contributing

Contributions are welcome!

You can help by:

🐛 Reporting issues
💡 Suggesting improvements
📝 Improving documentation
🔧 Submitting pull requests

📄 License

OCPP Client is dual licensed:

MIT License
Apache License 2.0

You may choose either license.

🏢 About Flowion

OCPP Client is developed by Flowion AB as part of our effort to make EV charging development more accessible through modern, open-source tooling.

Flowion builds software solutions for electric vehicle charging using open standards such as OCPP, helping developers and businesses build reliable and scalable charging infrastructure.

⭐ Support the Project

If you find this library useful:

⭐ Star the repository
🐛 Report issues
💡 Suggest improvements
🤝 Contribute

Together we can make EV charging development easier and more accessible.

ocpp-client 0.2.0