Experts in embedded RTOS, with a specialisation in safety certified software


Embedded RTOS for the Internet of Things (IoT)

The Internet of Things (IoT) is a term that’s become well known in recent years. It refers to a system of devices connecting the physical world to the internet. The opportunities that the IoT can provide affect every industry, and the possibilities are enormous.

Our IoT Solution

WHIS IoT solutions utilise Amazon FreeRTOS IoT software components, integrated with our renowned Real Time Operating Systems (RTOS), OPENRTOS® or SAFERTOS®.

For companies developing safety critical IoT applications, the Amazon FreeRTOS IoT software components are integrated with SAFERTOS. SAFERTOS replaces the FreeRTOS kernel, and provides isolation between safety critical code and the Amazon FreeRTOS IoT software by utilising the Task Isolation and Separation feature. More information about SAFERTOS here.

For companies using Amazon FreeRTOS IoT software in commercial applications who are seeking professional support or IoT Board Support Packages, we offer OPENRTOS. OPENRTOS is a commercially licensed alternative to the FreeRTOS kernel.

Start Your Development for Free

Start your development for free using Amazon FreeRTOS, and when you're ready, upgrade the FreeRTOS kernel to either SAFERTOS or OPENRTOS. They all share the same functional model, meaning migration is simple. We supply a manual for upgrading from the FreeRTOS kernel to SAFERTOS. Download it here.

Alternatively, if you require a IoT board support package, professional support or wish to start your development using either OPENRTOS or SAFERTOS then contact us today.

IoT RTOS Options

Amazon FreeRTOS is open source and is based on the FreeRTOS kernel, with the addition of libraries that enable local and cloud connectivity, security, and (coming soon) over-the-air updates. WHIS are able to replace the FreeRTOS kernel with our commercially licensed product OPENRTOS, or our safety critical product SAFERTOS. As they share a similar functional model as FreeRTOS, upgrading is simple. Existing FreeRTOS users can update their version to access the additional software libraries from AWS. For more information on the components that make up Amazon FreeRTOS, please see below.

Amazon FreeRTOS

The FreeRTOS kernel

The renowned FreeRTOS Real Time Operating System, freely distributed under an M.I.T. license from



Upgrade the FreeRTOS kernel to SAFERTOS. SAFERTOS provides developers with a responsive, deterministic embedded RTOS with a Design Assurance Pack that provides an easy route to achieving certification of SAFERTOS once integrated into a Safety Product.

SAFERTOS contains safety features such as Task Isolation and Separation, which allows developers to safely co-locate safety critical code with commercial grade code, using the processor's MPU/MMU. This means that safety code and the commercial grade Amazon FreeRTOS IoT software can be located within the same linear memory space, but still remain isolated from each other. More about SAFERTOS here.

OPENRTOS and Amazon FreeRTOS


OPENRTOS is a commercial license for the FreeRTOS kernel. If you need IP indemnification or professional support, OPENRTOS seamlessly replaces the FreeRTOS kernel while providing the same functionality. Contact us for more information about our flexible licensing and our professional support.

Strategic Business Alliance with Amazon Web Services

Since 2006, WHIS have offered commercial and safety critical upgrades for FreeRTOS. Now FreeRTOS is under the stewardship of Amazon Web Services (AWS), WHIS will continue to offer the same service for Amazon FreeRTOS. Our strategic business alliance with AWS enables us to offer state of the art IoT solutions with both OPENRTOS and SAFERTOS.

More on AWS

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Amazon FreeRTOS IoT Components

Amazon FreeRTOS is the FreeRTOS kernel with the addition of libraries that enable local and cloud connectivity, security, and (coming soon) over-the-air updates.

MQTT in Amazon FreeRTOS

Cloud Connectivity

Amazon FreeRTOS devices connect to the AWS cloud using MQTT based messaging. Amazon FreeRTOS facilitates easy onboarding with standard, vendor-independent library interfaces. MQTT is a lightweight protocol with a small footprint, enabling efficient communication for constrained, microcontroller-based devices.

Greengrass in Amazon FreeRTOS

Local Connectivity

Edge of Cloud devices running Amazon FreeRTOS can connect to local gateways running AWS Greengrass. The local gateways connect to the AWS cloud, however the cloud connection does not need to be permanent. The local gateways collect data from the Edge of Cloud devices, which they then store, and transmit to the cloud when connectivity is achieved.

The Edge of Cloud devices use the Greengrass Discovery software to identify and connect to local gateways running AWS Greengrass.

Wifi Management in Amazon FreeRTOS

Wi-Fi management

Amazon FreeRTOS devices can connect to the local network via Wi-Fi using local connectivity libraries such as the Wi-Fi management library. This library implements an abstraction layer for Wi-Fi features such as setup, configuration, provisioning, security, and power management.

Security in Amazon FreeRTOS

Secure cloud connection

Amazon FreeRTOS manages a secure connection to the cloud using Transport Layer Security (TLS v1.2). The TLS library implements an abstraction layer for the TLS protocol which provides privacy and data integrity between two communicating applications. In order to connect to the AWS IoT Core MQTT broker, TLS client certificate authentication is required.

Security in Amazon FreeRTOS

Key management

Amazon FreeRTOS provides an abstraction layer for cryptographic object management and private key signature operations as an important management feature. Cryptographic objects are kept either in dedicated storage or in the flash memory of the main microcontroller if dedicated storage is not available.

Security in Amazon FreeRTOS

Code Signing

The Amazon FreeRTOS code signing feature will verify the signed image on the device to ensure the device code is not compromised during deployment and updates.

Shadow Library

Support for AWS IoT Core Device Shadows

Amazon FreeRTOS supports the AWS IoT Core Device Shadow API. Device Shadows create a persistent, virtual version, or “shadow,” of each device that includes the device’s latest state so that applications or other devices can read its status and interact with the device.

OTA updates

Over-the-Air Updates BETA

Using the AWS IoT Device Management functionality with Amazon FreeRTOS devices provides an integrated Over The Air (OTA) update solution. Amazon FreeRTOS makes deploying OTA updates for microcontroller-based devices less memory intensive, by communicating those updates over a single TLS connection, shared with other AWS IoT Core communications.

From the AWS IoT Device Management console the firmware, the devices to update, the code signing method, and the update schedule can all be configured.