CyanogenMod is a discontinued open-source operating system for mobile devices, based on the Android mobile platform. It was developed as free and open-source software based on the official releases of Android by Google, with added original and third-party code, and based on a rolling release development model. CyanogenMod is designed to increase performance and reliability over Android-based ROMs released by vendors and carriers such as Google, T-Mobile, HTC, etc. CyanogenMod also offers a variety of features & enhancements that are not currently found in these versions of Android. Although only a subset of total CyanogenMod users elected to report their use of the firmware, on 23 March 2015, some reports indicated that over 50 million people ran CyanogenMod on their phones. It was also frequently used as a starting point by developers of other ROMs.
In 2013, the founder, Stefanie Kondik, obtained venture funding under the name Cyanogen Inc. to allow commercialization of the project. However, the company did not, in her view, capitalize on the project's success, and in 2016 she left or was forced out as part of a corporate restructure, which involved a change of CEO, closure of offices and projects, and cessation of services, and therefore left uncertainty over the future of the company. The code itself, being open source, was later forked, and its development continues as a community project under the LineageOS name.
CyanogenMod offered features and options not found in the official firmware distributed by mobile device vendors. Features supported by CyanogenMod included native theme support, FLAC audio codec support, a large Access Point Name list, Privacy Guard (per-application permission management application), support for tethering over common interfaces, CPU overclocking and other performance enhancements, unlockable bootloader and root access, soft buttons, status bar customisation and other "tablet tweaks", toggles in the notification pull-down (such as Wi-Fi, Bluetooth and GPS), and other interface enhancements. CyanogenMod did not contain spyware or bloatware, according to its developers. CyanogenMod was also said to increase performance and reliability compared with official firmware releases.
The name CyanogenMod derived from cyanogen (the name of a chemical compound adopted as a nickname by Kondik) + Mod (a term for user-developed modifications, known as modding).