Atom is a cross platform open source text/source code editor developed by GitHub written in C++, Node.js, Coffee Script, JavaScript, CSS. Atom offers a built-in package manager called APM to install packages developed by Atom developers and third-party developers. Atom is built on top of Chromium-based desktop application framework. The user can tweak atom UI. All the user must do is edit a simple stylesheet written in ‘less’. This stylesheet overrides the default config. The Atom UI can also be reset by cleaning the changes made me the user. Atom editor in active development, Atom by default has a limit of only a file of 2 MB which can be tweaked by the user if he wishes to open a larger file. Atom supports languages that other editor does not support (example: sass, scss).