Contiki-NG vs FreeRTOS

Contiki-NG is a free, open-source operating system for resource-constrained Internet of Things devices, designed for 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 below IPv6. Documented modules include IPv6 multicast, OMA LWM2M, 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; CSMA link-layer security is described as planned. Documented hardware includes TI, Nordic, Silicon Labs, OpenMote, Tmote Sky/TelosB, and Zolertia boards. Development resources include Cooja native motes, a Renode tutorial, Docker, and native Linux and macOS toolchain setup. It is available for Linux, macOS, Windows, and self-hosted environments, and source code is distributed under the 3-clause BSD license unless otherwise specified.

FreeRTOS is a real-time operating system for microcontrollers and small microprocessors. It supports more than 40 processor architectures and more than 15 toolchains, including RISC-V and ARMv8-M. Its kernel includes Symmetric Multiprocessing, which can schedule tasks across identical processor cores that share memory, and a thread-safe TCP stack with IPv6 support. Libraries for AWS IoT services are included, with reference integrations that demonstrate security practices. FreeRTOS is distributed under the MIT open source license and can be used for any purpose under that license. LTS libraries receive security updates and critical bug fixes for two years. Preconfigured demos are available for official ports, and Windows and Linux ports plus QEMU projects let developers experiment without special hardware. The listed plan costs nothing. Community contributions and professional support through a partner ecosystem are also listed; commercial licenses and safety certification are available through a strategic partner.