SharePoint Framework(SPFx) is a client side development framework that leverages CSOM, REST APIs, Microsoft Graph and more. Development is done through utilizing open source technologies like Node.js, Gulp, Yeoman, VSCode and more. It supports SharePoint Online and SharePoint 2016 (SP2)+ on-premise solutions.

Key benefits of using SPFx are

1. It utilizes context of current user.
2. It enables use any JavaScript Framework. React, Knockout, Angular etc
3. Controls are responsive.
4. Web parts can be used by both classic and modern pages

Previous models like JSLink and SP Add-in had their limitations. JSLink restricted scripts if not marked with “Safe for Scripting” and Add-ins were using IFrame model which are inefficient in modern websites.

Ready to try SPFx. Start with Hello World