Scratch brings together millions of young people world wide in creating digital projects fueled by their passions and creativity. The Scratch online community and its collaborative culture of remixing enables children to share these projects in a supportive online community, building creative confidence.

With the launch of the newest version of Scratch, the community will be able to create in new ways, combining their digital creations with the physical world. Scratch 3.0 is introducing a new system of Extensions, sets of blocks that extend the Scratch programming environment by connecting it to online services and hardware devices in an interoperable environment. Scratch 3.0 extensions have all the power of the Scratch programming language and operate within the Scratch virtual machine so that users can tinker with their code and get live feedback.

In this talk, we will discuss the Scratch 3.0 extension system, the design process surrounding creating some of the existing extensions, and the process and guidelines for being able to create your own extensions to the Scratch 3.0 environment.