FreeRTOS FAQs

Developed over an 18-year period and in partnership with the world's leading chip companies, the FreeRTOS kernel is the market-leading, real time operating system kernel and the de-facto standard solution for microcontrollers and small microprocessors.

Yes. The latest update to v10 of the FreeRTOS kernel includes support for RISC-V and Armv8-M (Cortex-M33 and Cortex-M23).

Both licenses allow the software to be used for free, even in commercial products, and neither license imposes any obligations when distributing binary (executable) copies. The MIT license provides simplified wording and allows for more permissive use of our source code. With the MIT license, you can still develop and sell commercial products using FreeRTOS (including the kernel) but you are no longer obliged to open source modifications to our source code, meaning you own all the changes you make. The only requirements under MIT is that the copyright notice and permission notice shall be included in all copies or substantial portions of the software (source files).

The FreeRTOS LTS release includes the kernel and libraries needed for AWS IoT connectivity, security, and over-the-air (OTA) updates. See the complete list of LTS libraries here.

The support period for FreeRTOS LTS libraries is two years. FreeRTOS LTS libraries will not have any feature development and will include security updates and bug fixes that AWS determines as critical for at least two years from its release.

You can get the FreeRTOS LTS libraries by cloning the FreeRTOS LTS GitHub repository, cloning individual LTS libraries, or by downloading the FreeRTOS LTS zip file from FreeRTOS.org.

You can update individual libraries to LTS libraries by cloning them from their corresponding repositories. For example, you can update your project to the FreeRTOS LTS MQTT library by downloading code from the coreMQTT GitHub repository.

You can visit the ‘FreeRTOS LTS Patches’ section in the LTS Libraries page on FreeRTOS.org for the latest information, or subscribe to GitHub notifications for the FreeRTOS LTS repository. FreeRTOS LTS releases use a date-based versioning scheme (YYYYMM) followed by a patch sequential number (.XX). For example, FreeRTOS 202012.02 LTS means the second patch to the December-2020 FreeRTOS LTS release. You can get the latest patch from GitHub by using the associated download link.

FreeRTOS LTS libraries are distributed free under the MIT open source license.

No. FreeRTOS LTS libraries are free for all users under the MIT open source license.

AWS will release and provide ongoing maintenance of the FreeRTOS LTS libraries for the benefit of the FreeRTOS community. The FreeRTOS community is encouraged to provide feedback and contribute code in the form of GitHub pull requests.

We expect new FreeRTOS LTS releases to happen every 1.5 years.

We aim to address security vulnerabilities and critical bugs on FreeRTOS LTS libraries within seven days from successfully implementing a mitigation to releasing an update.

Yes, see the FreeRTOS Extended Maintenance Plan.

Visit the FreeRTOS LTS GitHub repository and include the libraries you need for your application.

FreeRTOS LTS kernel versions are backward compatible with FreeRTOS kernel versions V8.0.0 or higher. So if you are already using FreeRTOS kernel versions v8.0.0 or higher, you can migrate to the latest kernel version in the LTS release with minimal changes to your application code.

If you are using an older version of LTS libraries, see the migration guide and corresponding validation tests to upgrade your project to FreeRTOS LTS.

AWS IoT Device Tester for FreeRTOS is a Windows/Linux/Mac test automation tool that lets semiconductor vendors self test and qualify FreeRTOS on their microcontroller boards. With AWS IoT Device Tester, semiconductor vendors can verify whether their microcontroller boards can run FreeRTOS and be authenticated by and interoperate with AWS IoT services.

You can get AWS IoT Device Tester for FreeRTOS here.

Yes, you can learn more about how to get listed here.

AWS IoT Device Tester for FreeRTOS tests that the combination of a FreeRTOS IoT reference integration with a microcontroller board’s porting layer interfaces and underlying device drivers are compatible and can interoperate with AWS IoT services. AWS IoT Device Tester confirms the porting layer interfaces (implemented by semiconductor vendors) for FreeRTOS libraries function correctly on top of the device drivers. Also, AWS IoT Device Tester runs end-to-end tests to confirm the microcontroller board can authenticate and interoperate with AWS IoT services.

Use any of the following channels to get support:

• Premium Support
• Customer Support
• GitHub Issues

The AWS Device Qualification Program defines the process to get your microcontroller listed on AWS Partner Device Catalog. The high-level overview is as follows: First, you must pass the AWS IoT Device Tester for AWS FreeRTOS tests. Next, log into the AWS Partner Network Portal and upload the AWS IoT Device Tester for FreeRTOS report. Provide reference to your source code for ported FreeRTOS interfaces to make it available to OEMs. Once the ported code and report are verified by AWS and other device related artifacts (such as device image, data sheet, etc.) have been submitted, the device is listed in the AWS Partner Device Catalog.

AWS IoT Device Tester for FreeRTOS is available in all the regions where FreeRTOS is supported.  

AWS IoT Device Tester for FreeRTOS is free to use. However, you will be responsible for any costs associated with AWS usage as part of qualification tests. On average, a single run of the AWS IoT Device Tester would cost less than a cent. Please refer to AWS IoT Core pricing for associated costs.

AWS IoT Device Tester for FreeRTOS is a Windows/Linux/Mac test automation tool that lets semiconductor vendors self test and qualify FreeRTOS on their microcontroller boards. With AWS IoT Device Tester, semiconductor vendors can verify whether their microcontroller boards can run FreeRTOS and be authenticated by and interoperate with AWS IoT services.

You can get AWS IoT Device Tester for FreeRTOS here.

Yes, you can learn more about how to get listed here.

AWS IoT Device Tester for FreeRTOS tests that the combination of a FreeRTOS IoT reference integration with a microcontroller board’s porting layer interfaces and underlying device drivers are compatible and can interoperate with AWS IoT services. AWS IoT Device Tester confirms the porting layer interfaces (implemented by semiconductor vendors) for FreeRTOS libraries function correctly on top of the device drivers. Also, AWS IoT Device Tester runs end-to-end tests to confirm the microcontroller board can authenticate and interoperate with AWS IoT services.

Use any of the following channels to get support:

• Premium Support
• Customer Support
• GitHub Issues

The AWS Device Qualification Program defines the process to get your microcontroller listed on AWS Partner Device Catalog. The high-level overview is as follows: First, you must pass the AWS IoT Device Tester for AWS FreeRTOS tests. Next, log into the AWS Partner Network Portal and upload the AWS IoT Device Tester for FreeRTOS report. Provide reference to your source code for ported FreeRTOS interfaces to make it available to OEMs. Once the ported code and report are verified by AWS and other device related artifacts (such as device image, data sheet, etc.) have been submitted, the device is listed in the AWS Partner Device Catalog.

AWS IoT Device Tester for FreeRTOS is available in all the regions where FreeRTOS is supported.  

AWS IoT Device Tester for FreeRTOS is free to use. However, you will be responsible for any costs associated with AWS usage as part of qualification tests. On average, a single run of the AWS IoT Device Tester would cost less than a cent. Please refer to AWS IoT Core pricing for associated costs.

AWS IoT Greengrass is software that lets you run local compute, messaging, data caching, sync, and ML inference capabilities for connected devices in a secure way. With AWS IoT Greengrass, connected devices can run AWS Lambda functions, keep device data in sync, and communicate with other devices securely – even when not connected to the Internet. Using AWS Lambda, AWS IoT Greengrass ensures your IoT devices can respond quickly to local events, use Lambda functions running on AWS IoT Greengrass Core to interact with local resources, operate with intermittent connections, stay updated with over the air updates, and minimize the cost of transmitting IoT data to the cloud.

FreeRTOS is an open source, real time operating system for microcontrollers that operates on the edge and does not generally support chipsets that could run AWS IoT Greengrass. These microcontroller devices are found on a variety of IoT endpoints such as fitness trackers, pacemakers, electricity meters, automotive transmissions, and sensor networks. FreeRTOS devices cannot run AWS IoT Greengrass Core but can trigger the execution of Lambda functions on an AWS IoT Greengrass Core device.

The hardware requirements and operating systems are different on both devices.

FreeRTOS does not require the use of AWS IoT Greengrass. FreeRTOS runs on IoT endpoints and is often responsible for the "sensing" and "acting" in an IoT topology. FreeRTOS devices can connect directly to the cloud or connect to AWS IoT Greengrass Core devices locally.

The AWS IoT Greengrass discovery library is included in the FreeRTOS source code, enabling you to find and connect to an AWS IoT Greengrass Core device. For more information, refer to the FreeRTOS user guide.

Bluetooth Low Energy support in FreeRTOS offers a standardized API layer for developers to write Bluetooth Low Energy applications that are portable across FreeRTOS qualified boards. It includes companion Android and iOS SDKs that enable a FreeRTOS device to consume AWS IoT services using an Android or iOS device as proxy. You can use standard Generic Access Profile (GAP) and Generic Attributes (GATT) profiles to write Bluetooth Low Energy applications and use custom profiles for MQTT over Bluetooth Low Energy and Wi-Fi provisioning via Bluetooth Low Energy. You can also use other AWS IoT services and features including AWS IoT Device Defender, Device Shadows, and over-the-air (OTA) updates.

If you are an embedded developer that needs to create a Bluetooth Low Energy application, connect your Bluetooth Low Energy devices to AWS IoT through an Android or iOS proxy, or use AWS IoT features such as AWS IoT Device Shadows, you will benefit from using Bluetooth Low Energy in FreeRTOS. The standardized Bluetooth Low Energy API for FreeRTOS allows you to code portable applications against FreeRTOS-qualified devices. If you decide to use a different microcontroller (e.g. for upgrading the product), you can use your existing Bluetooth Low Energy application code as a base for adding newer features. You can then concentrate on your application code and not worry about connectivity and security libraries underneath, which are not features that differentiate your product.

Visit our getting started page for more information on supported hardware.

You can select the board and download the ported code via AWS Partner Device Catalog. FreeRTOS source code has demo examples, and the mobile SDKs have sample applications to help you quickly get started.

No. The FreeRTOS libraries for Bluetooth Low Energy are open source and under the MIT license so developers can modify according to their specific need.

FreeRTOS supports Bluetooth Low Energy versions 4.2 and above. Bluetooth Low Energy version 4.2 raises the security bar by adding support for Bluetooth Low Energy Secure Connections, an enhanced security feature introduced in Bluetooth Low Energy version 4.2 to authenticate a peer device and create an encrypted channel.

No. FreeRTOS is providing a standardized Bluetooth Low Energy API library that interfaces with a third-party (e.g., MCU vendor) Bluetooth Low Energy stack.

Bluetooth Low Energy support in FreeRTOS enables developers to add any number of standard and custom GATT services, depending on the capabilities of the target hardware. FreeRTOS contains two customer profiles: 1) MQTT over Bluetooth Low Energy, to enable Bluetooth Low Energy devices to use AWS IoT services, and 2) Wi-Fi provisioning over Bluetooth Low Energy, to provision Wi-Fi credentials in an IoT device using Bluetooth Low Energy.

Currently, there is no mechanism to intercept messages flowing between a Bluetooth Low Energy device and AWS IoT. The Bluetooth Low Energy proxy only acts as a pass-through device.

However, you can use methods and classes that are provided within the proxy libraries as a starting point and modify these libraries to intercept the messages and take local action.

MQTT over Bluetooth Low Energy enables Bluetooth Low Energy devices to connect to AWS IoT via a proxy device, as well as enables you to use other AWS services and features including AWS IoT Device Defender, AWS IoT Device Shadows, and FreeRTOS over-the-air (OTA) updates.

Yes. You can use MQTT over Wi-Fi and MQTT over Bluetooth Low Energy simultaneously as long as your device has the memory required to do so.

AWS IoT uses the Amazon Cognito service to authenticate mobile devices with cloud services. However, you can also use X.509 certificates that are supported by FreeRTOS mobile SDKs to authenticate your proxy device with AWS IoT.

We have a preview FreeRTOS cellular library that makes it easier to develop secure LTE-M (or CAT-M1) IoT solutions. New reference integrations and demonstration projects are available from our partners Quectel, Sierra Wireless, and u-blox.

The FreeRTOS cellular library supports LTE-M cellular modems. LTE-M is a type of low power wide area network (LPWAN) radio technology standard developed by 3GPP to enable a wide range of cellular devices and services.

Currently, the FreeRTOS cellular library offers interoperability across the following LTE-M modems: Quectel BG96, Sierra Wireless HL7802, and u-blox SARA-R4.

Source code for the FreeRTOS cellular library and IoT reference integrations are available on the FreeRTOS Labs repository on GitHub.

You can use the over-the-air (OTA) update feature of FreeRTOS. Within the AWS IoT Device Management console, all you need to do is provide a firmware image, select the devices to update, select a code signing method, and create the FreeRTOS OTA job update. For more information on the OTA update feature and code signing, refer to the FreeRTOS user guide.

Code signing enables developers to confirm the integrity and origin of firmware images scheduled for over-the-air (OTA) deployment to FreeRTOS devices. The process confirms the integrity of firmware images using a cryptographic hash that validates that the code has not been altered or corrupted since it was signed. The process also uses public-key cryptography to sign these images with proof of origin that can be validated on the device. Using the integrated FreeRTOS OTA update device job within the AWS IoT Device Management console, developers can upload a new firmware image, sign that image, and deliver it to a group of devices in the field. Those devices will validate the signature upon download and only install trusted code. Customers can use IAM to provide fine-grained access controls to signing tools, so only designated developers can sign and schedule new firmware updates.

No, you can also use your own signing service and upload a signed image directly into Amazon S3. You will need to modify the FreeRTOS over-the-air (OTA) agent to accept the signature format that you choose to use.

You can find qualified hardware that support FreeRTOS OTA in the AWS Partner Device Catalog.

FreeRTOS uses Transport Layer Security (TLS 1.2) for secure connections to the cloud. The TLS protocol ensures privacy and data integrity between two communicating applications. It ensures that a FreeRTOS device and the cloud server are mutually authenticated using X.509 certificates and that data is encrypted while it is in transit.

FreeRTOS uses a standard application interface, called PKCS #11, for encryption, digital signatures, and cryptographic object management. Cryptographic objects are kept either in dedicated storage or in the flash memory of the main microcontroller if dedicated storage is not available. If your device requires data encryption at rest, we recommend that you use dedicated cryptographic hardware to protect your encryption keys. Use the PKCS #11 API to access keys and encrypt and decrypt application data.

Security updates are provided via the FreeRTOS console, the FreeRTOS Security Updates page, and on GitHub.

To report a security issue, please visit Vulnerability Reporting for AWS.

We recommend that you use the over-the-air (OTA) update feature of FreeRTOS to send security patches to your FreeRTOS devices. Within the AWS IoT Device Management console, you can provide a firmware image, select the devices to update, and create the FreeRTOS OTA job update. The code signing feature will verify the signed image on the device to ensure your device code is not compromised during deployment and updates. For more information on the OTA update feature, refer to the FreeRTOS user guide.

FreeRTOS Extended Maintenance Plan (EMP) provides you with security patches and critical bug fixes on your chosen FreeRTOS Long Term Support (LTS) version for up to 10 years beyond the expiry of the initial LTS period. With FreeRTOS EMP, your FreeRTOS-based long-lived devices can rely on a version that has feature stability and receives security updates during the term of your subscription. You receive timely notification of upcoming patches on FreeRTOS libraries, so you can plan the deployment of security patches on your Internet of Things (IoT) devices. Before the end of the current LTS period, you will be able to subscribe to Extended Maintenance Plan using your AWS account, and renew the subscription annually to cover the product lifecycle or until you’re ready to transition to a new FreeRTOS release. FreeRTOS EMP applies to libraries that are part of FreeRTOS LTS.

FreeRTOS EMP helps you maintain your FreeRTOS-based devices during the term of your subscription. It allows you to save operating system upgrade costs and reduce the risks of not being able to update devices in time. It provides security patches and critical bug fixes on feature-stable FreeRTOS LTS versions, so you don’t need to incur development, testing, and quality assurance costs to migrate to the latest FreeRTOS release. Updating devices involves project planning, release readiness testing, and over-the-air (OTA) update scheduling to deploy critical fixes. FreeRTOS EMP reduces the risk of delayed deployment by providing timely notification of upcoming patches and support with integration issues.

* A critical bug is a defect determined by AWS to impact the functionality of the affected library and has no reasonable workaround.

AWS will provide technical support to FreeRTOS EMP customers via AWS Support. AWS Support is not included in FreeRTOS EMP subscriptions. You can track issues (for example, issues related to AWS accounts, billing, or bugs) or get access to technical experts (on issues such as patch integration) based on your AWS Support plan.

FreeRTOS EMP has a flexible subscription option that can be extended annually for up to 10 years. You can extend your subscriptions for a duration that aligns with your device lifecycle or application requirements. See the pricing page for more details.

Contact us to get started.

No. FreeRTOS EMP has a flexible annual subscription plan. You can continue to renew your subscriptions annually for a duration (up to 10 years) that aligns with your device lifecycle or application requirements.

Under NDA, AWS will notify you via official AWS Security channels of an upcoming patch and its timelines (if AWS is reasonably able to do so and deems it appropriate). Patches will be available through the FreeRTOS EMP Console within three business days of successfully implementing and getting AWS Security approval for our mitigation. If the libraries are also part of the current FreeRTOS LTS release, patches will be publicly available in the FreeRTOS LTS GitHub repository. 

FreeRTOS EMP will be available for the current and all previous FreeRTOS LTS releases. Subscriptions can be renewed annually for up to 10 years from the end of the chosen LTS version’s support period. For example, a subscription for FreeRTOS 202012.01 LTS, whose LTS period ends March 2023, may be renewed annually until March 2033.

FreeRTOS EMP consists of an initial base code (LTS version) and subsequent patches for security vulnerabilities and critical bug fixes. FreeRTOS base code continues to be licensed under the MIT open source license. Any code, fixes, or patches (collectively, “Patches”) that you receive, obtain or access in connection with FreeRTOS EMP that have not been incorporated into the publicly available FreeRTOS libraries are provided to you under the AWS Intellectual Property License except that in addition to the rights granted under the AWS Intellectual Property License, AWS also grants you a limited, non-exclusive, non-sublicensable, non- transferrable license to (a) modify and create derivative works of the Patches and (b) to distribute the Patches in object code form only. See AWS Service Terms for more details.

Contact AWS Sales if you are interested in longer terms.

It depends. Each FreeRTOS LTS version will have its own subscription. If you buy a multiple-product subscription, you pay for only one subscription when you use the same FreeRTOS LTS version for multiple end products. If you buy a single-product subscription, you can use your subscription for only one end product (see next FAQ for the definition of a product).

A customer product is the result of a manufacturing process and is in the market under a specific name or order code. Two customer products are separate if they have significant hardware and/or functional differences, have different product names, or have different types, models or variants. The use of FreeRTOS in more than one customer product will require the purchase of an additional, separate license for each customer product or the purchase of a multiproduct license.

AWS will provide technical support for FreeRTOS EMP customers via separate subscriptions to AWS Support. AWS Support is not included in FreeRTOS EMP subscriptions. You can track issues or speak to technical experts based on your AWS Support plan. See details on AWS Support plans here.

You can get support for your billing questions via AWS Support.

Yes. You can use the FreeRTOS EMP libraries to suit your specific application need. However, you must have or sign up for an AWS account to subscribe to FreeRTOS EMP.

FreeRTOS EMP patches include security updates and bug fixes that AWS determines to be critical for libraries in your FreeRTOS EMP project.

A critical bug is a defect determined by AWS to impact the functionality of the affected library and has no reasonable workaround. We will determine the need for a fix based on the impact of the defect (e.g. vulnerability, inoperability, or impaired functionality) on a case-by-case basis.

No. AWS will provide fixes and support for the baseline LTS library source code only.

An escalation takes place when AWS Support transfers a technical support case to the FreeRTOS engineering team for a resolution. FreeRTOS EMP customers need to be AWS Support subscribers to be eligible for these escalations.

You can escalate four (for single product subscriptions) and six (for multiple product subscriptions) AWS Support cases per year at no additional charge. After that, you may incur charges (evaluated case by case) in addition to the AWS Support fees. In case of charges, AWS will request your confirmation to proceed and charge at a rate of $3,100 per Software Development Engineer per week (without proration).

Yes, FreeRTOS EMP subscriptions (once available) can be canceled anytime during the subscription period.

You are obligated to pay for a minimum of one year of subscription each time you register to receive the service. We reserve the right to refuse to provide FreeRTOS EMP support to any customer that frequently registers for and terminates the service.

Renewing your subscriptions annually to match your product lifecycle helps you better manage the security of your devices throughout their lifecycle. The security teams at AWS are continuously working to identify potential security vulnerabilities in FreeRTOS libraries, which helps you become aware of security issues timely and proactively plan for the deployment of patches. If there is a lapse in your subscription, you will incur a one-time fee and other costs that might affect your total cost of the subscription. See the pricing page for details.

You can continue to renew your Extended Maintenance subscriptions annually for up to 10 years. You may terminate your subscription at any time. AWS may terminate Extended Maintenance for any version of LTS as permitted under the agreement governing your use of AWS services, including upon at least 12 months' notice for any reason. Upon any termination of Extended Maintenance for an LTS version, your subscription to Extended Maintenance for such LTS version will also terminate.