Contiki-NG vs OpenWrt

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.

OpenWrt is a Linux operating system for embedded devices, commonly wireless routers. Its writable filesystem and optional package management let users customize devices by adding packages; the project lists more than 27,000 packages and services. Configuration is available through an SSH command-line interface or a web interface, and the Table of Hardware helps check device support before installation. Hardware capacity is a key consideration: OpenWrt identifies 8 MB flash and 64 MB RAM as bare minimums, while warning against devices at those limits for current, secure use. The downloads page lists OpenWrt 25.12.5 as the current stable release and describes development snapshots as generally untested. The older 24.10 release is slated to receive limited security and bug fixes for some time. OpenWrt is free software, with no subscription or licensing fees. The project says users should know GNU/Linux and basic networking concepts before installing it; voluntary support from developers and users is not guaranteed.