Contiki-NG

Contiki-NG is an open-source operating system for resource-constrained Internet of Things devices, designed around low-power communication and standard protocols. Its code footprint is on the order of 100 kB, and memory use can be configured as low as 10 kB. The IPv6 stack includes TCP, UDP, DNS, RPL, CoAP, LWM2M, and WebSockets, with IEEE 802.15.4 and TSCH support beneath IPv6. Documented modules also cover IPv6 multicast, secure CoAP, 6TiSCH, and SNMP. Security documentation describes DTLS with Mbed TLS, pre-shared keys or certificates, and EDHOC key exchange. Link-layer security is supported for IEEE 802.15.4 TSCH; support for CSMA is described as planned. Documented hardware includes boards from TI, Nordic, Silicon Labs, OpenMote, Tmote Sky/TelosB, and Zolertia. Development resources include Cooja native motes, a Renode tutorial, a recommended Docker image, and native toolchain installation for Linux and macOS. The software is free under the 3-clause BSD license unless otherwise specified.

Contiki-NG targets constrained IoT hardware with a broad set of networking modules and security options. Check the documented board support and the CSMA security limitation against your project needs.

Contiki-NG suits developers building low-power IoT devices with constrained memory and standard network protocols. Its documented board support, simulation resources, and Linux or macOS toolchains may help teams developing at the edge.

Contiki-NG is an open-source operating system for resource-constrained Internet of Things devices. It is best suited to developers building low-power edge nodes on supported hardware and using standard networking protocols. Its small memory footprint and broad protocol stack make it a focused option for constrained devices, but its CSMA link-security gap can rule it out for some deployments.

Overview

With a code footprint on the order of 100 kB and configurable memory use as low as 10 kB, Contiki-NG is designed for devices where every byte matters. That makes it relevant for small edge nodes, rather than projects looking for a general-purpose operating system. Its resource-efficient IPv6 stack covers TCP, UDP, DNS, and RPL, alongside CoAP, LWM2M, and WebSockets; IEEE 802.15.4 and TSCH sit beneath IPv6.

MQTT is supported through documented integration guidance, including a Linux setup guide that uses Mosquitto and its clients. The project recommends Docker for a consistent development environment and also documents native toolchain installation on Linux and macOS. That gives teams a documented route to development, though the operating system itself remains aimed at embedded deployments.

Key features

Protocols and security

Documented modules include IPv6 multicast, RPL, CoAP and secure CoAP, OMA LWM2M, TSCH/6TiSCH, and SNMP. DTLS through Mbed TLS supports pre-shared keys or certificates. EDHOC is another option, providing mutual authentication, forward secrecy, and identity protection according to the project documentation. This breadth makes Contiki-NG a strong candidate when a constrained device needs established IoT protocols and documented security mechanisms.

The important caveat is link-layer security: it is supported for IEEE 802.15.4 TSCH, while CSMA link-layer security is planned. If a design depends on protecting CSMA links now, Contiki-NG is not the right choice without another approach to that requirement.

Hardware and simulation

Documented hardware includes TI cc2538 and SimpleLink, Nordic nRF52840 and nRF5340, Silicon Labs Gecko, OpenMote, Tmote Sky/TelosB, and Zolertia Zoul boards. The supported-device operating-system targets also include ARM Cortex-M3/M4, TI MSP430, and TI CC13xx/CC26xx. Cooja native motes and a Renode tutorial give developers documented simulation paths before deployment. These options are useful when a project aligns with the listed boards and targets; hardware outside that range calls for a support check before committing.

Pricing

Contiki-NG is free: its plan costs nothing and provides an open-source operating system under the 3-clause BSD license, unless otherwise specified for particular source code. There is no free trial because the software is offered as a free plan. This suits teams that want to use or adapt an open-source embedded OS without a paid entry tier; there are no published seats, quotas, or renewal terms to weigh.

Platforms

The listed platforms are Linux, macOS, Windows, and self-hosted. These describe the environments associated with the software, while the device targets are embedded hardware such as ARM Cortex-M3/M4, TI MSP430, TI CC13xx/CC26xx, and Nordic nRF5340/nRF52840. Linux and macOS have documented native toolchain installation, and Docker is recommended for a consistent development setup.

Who it's for

Contiki-NG fits developers building low-power IoT devices that need a small footprint, IPv6 networking, and protocols such as CoAP, LWM2M, TSCH/6TiSCH, or MQTT integration. Its documented boards and simulation options suit teams that can work within those hardware paths. It is a weaker fit for projects that require CSMA link-layer security or depend on hardware without a documented support path.

Pros and cons

Pros

• Low resource requirements: a code footprint on the order of 100 kB and memory configurable as low as 10 kB target devices with tight budgets.
• Broad IoT networking: IPv6, TCP, UDP, DNS, RPL, CoAP, LWM2M, WebSockets, TSCH, and documented MQTT integration cover a range of constrained-device needs.
• Multiple documented security mechanisms: DTLS with Mbed TLS, secure CoAP, pre-shared keys or certificates, and EDHOC address authentication and confidentiality needs.
• Free and open source: the free plan and 3-clause BSD license make it accessible for teams adopting or adapting the OS.

Cons

• CSMA link security is only planned: projects requiring that protection cannot rely on it as a supported feature.
• Hardware fit matters: the documented boards and device targets define the clearest adoption path, so other hardware needs validation.

Alternatives

Apache Mynewt is another free open-source embedded OS and development-tools option under the Apache License 2.0; consider it when that license or toolset better fits the project.

Particle Device OS is worth considering for teams that want a freemium platform with a free tier for 100 devices and 100K Data Operations per month, rather than a free open-source OS focused on constrained hardware.

PX5 RTOS may suit buyers looking for device or product licensing, including a perpetual license, full source code, no royalties, and professional support; its listed one-time package starts at $5,000.

VxWorks is an alternative for readers considering a freemium offering with up to 3 seats online.

Azure Sphere OS is an alternative for readers seeking a bundled certified MCU, OS license, security-service access, and ongoing OS updates.

Micrium OS, RT-Thread, and TencentOS Tiny are other free operating-system options.

Browse the IoT Operating Systems list for more choices.

Verdict

Choose Contiki-NG for low-power IoT devices when its small footprint, protocol coverage, and documented hardware targets match the design. Its free, open-source model is compelling for teams building within those constraints. Look elsewhere if CSMA link-layer security is essential or the target hardware does not align with its documented support.