Our operating system framework is built of just 5 components, enabling tailor-made solutions for every use case.

A Flexible Toolkit

The L4Re OS Framework

Just 5 core components of the L4Re Operating System Framework enable high-security system solutions – tailor-made for your needs.

Unique & unequalled

What is L4Re?

The L4Re Operating System Framework is the most advanced capability-based operating system on the market – and the only certifiable open-source hypervisor.

L4Re, based on the L4 microkernel, is more than the sum of its parts. It is made of a framework and an operating system. The framework parts are generic and follow the multipurpose approach, which means they can be applied to diverse use cases.

Because it is built out of several modules and because we co-designed microkernel and userland components, L4Re has a unique architecture with uniform APIs across the whole system.

Additionally, L4Re is supported by an extensive range of quality assurance tools and tests, as well as the application of formal methods to ensure all components work correctly and reliably.

L4Re Operating System Framework

A minimal TCB for your system

Kernkonzept uses the L4Re Operating System Framework as a platform to develop tailor-made L4Re-solutions for very different customer needs – a minimal trusted computing base (TCB), customized to any given need.

With our toolkit of 5 core components we can build a minimal operating system and hypervisor solution following POLA, enabling Zero Trust and thus providing Security by Design to our customers.

L4Re Microkernel

Our state-of-the-art microkernel features latest advances in security design by providing capabilities and local namespaces for applications; other systems feature these as an afterthought only. The L4Re Microkernel is the foundation of the L4Re Operating System and Hypervisor Framework. It allows the construction of flexible, static, or dynamic systems for real-time, time sharing and virtualization applications.

It scales seamlessly from small embedded systems to big server machines with hundreds of CPUs and terabytes of RAM. It can be used as separation kernel or with more operating system functionalities.

L4Re Core Foundation

L4Re Core Foundation provides fundamental software services and abstractions for the L4Re Operating System and Application Services. The L4Re Microkernel and L4Re Core Foundation are co-designed so that they provide a generic interface that does not mandate any use-case.

For compatibility with existing software, L4Re Core Foundation supports a selected set of POSIX and C++ standard APIs. This makes porting existing software easier protecting your investment while you can instantly profit from the enhanced security capabilities of the L4Re Operating System Framework.

L4Re Operating System Services

The L4Re Operating System Services provide essential operating-system services for your application. The L4Re Operating System Framework includes, but is not limited to, services for storage (MMC, AHCI, NVMe), virtual networking between applications based on Virtio and GUI.

L4Re Operating System Libraries

The L4Re Operating System Libraries are a set of libraries that are used to implement the L4Re Operating System Services. You can also use these libraries to implement your own services. The L4Re Operating System Framework includes libraries for basic application support such as a libc and C++ standard library, as well as virtio, device drivers, and event handling.

L4Re Application Services

The L4Re Application Services provide services for other applications and are the applications themselves. This can be a native L4 application, called Micro-App, or a virtual machine (VM) that hosts your existing applications.

See our list of Board Support Packages (BSPs) that are already supported by the L4Re Operating System Framework.

Features of L4Re

Secure, safe & state-of-the-art

Since I started working on L4Re at university, I’ve been excited about solving problems by using L4Re. Today, I do that every day as a key account engineer for our customers.

Matthias, Customer Success Engineer

Minimal & Secure

Microkernel-based architecture

The Principle Of Least Authority (POLA) is the soul of the L4Re Operating System Framework. Uniform APIs and object capabilities make our microkernel-based software a benchmark in certification-ready high-security software.

SOC Security

The L4Re Micro Hypervisor

The L4Re Micro Hypervisor for MPU-based systems extends the range of our open-source L4Re Operating System Framework to also work on very small safety-critical systems.

The L4Re Micro Hypervisor securely separates real-time workloads even on very small chips, making it the perfect application for the automotive industry, avionics, or the IoT. It is included as reference hypervisor with NXP’s S32Z/E Vehicle Integration Platform called GreenVIP.

German GEHEIM Label

Certified & accredited

Ready for Certification

The components of the L4Re Operating System Framework enable customized system solutions – unique, minimal, and specific for your use case.

What’s best is the readiness of our open-source software for various safety and security certifications, be it Common Criteria EAL4+ or ASIL/ISO 26262.

Our L4Re Secure Separation Kernel has been approved by BSI for processing classified information up to German GEHEIM in 2024.

State of the Art

Security by design

The L4Re Operating System Frameworks modular architecture is based on decades of experience. Its object based capabilities are unique and state of the art, distinguishing it from all kinds of other security software.

L4Re enables unique and minimal system solutions. With uniform interfaces and APIs we can implement use-case specific policies and rules without bloating critical parts of the system or influencing independent components. This is security by design – elegant and highly functional.

Empowering open-source solutions

L4Re supports RISC-V

The L4Re Operating System Framework and Hypervisor also supports RISC-V, allowing us to implement L4Re to a wider range of applications, from embedded systems to high-performance computing.

By combining our open-source software L4Re with the open architecture RISC-V, we can provide more customers with our state-of-the art security software, enhancing their system integrity.


Debugging by Lauterbach

The L4Re Hypervisor and Micro Hypervisor are supported by the Lauterbach TRACE32® debugger. With the off-chip debugging solution of the world’s largest provider of low-level software debugging and tracing tools, you can comfortably bring up and optimize your software setups based on the L4Re Operating System Framework.

Lauterbach’s debugging tools support a wide range of processors and platforms. They are also aware of the operating system software running on the targets. This OS awareness includes the L4Re Operating System Framework, both on MMU and MPU based systems, and it allows debugging of the L4Re Hypervisor, L4Re applications and the guests with their applications.

Get in touch

Your personal contact

Our Head of Microkernel Development Adam Lackorzynski will introduce you to our L4Re framework and set you up for your specific needs.