Atom is described as 'Open-source, Electron based text editor with a massive ecosystem of plugins and themes that are easily accessible through a built-in package manager. Being built with Electron, it uses web technology (HTML, CSS, JavaScript and Node' and is a leading Code Editor in the development category. There are more than 100 alternatives to Atom for a variety of platforms, including Windows, Linux, Mac, BSD and Web-based apps. The best Atom alternative is Visual Studio Code, which is free. Other great apps like Atom are Notepad++, Sublime Text, Vim and VSCodium.
Graviton is very lightweight compared to Atom and it does not send any data to any server. Its plugin system is still young but it's almost at the level of Atom's.