WebAssembly filters allow users the power to extend and customize Istio to their liking. But how do organizations actually develop them? Tooling exists for traditional software development, but established methods and tooling are difficult to come by in the emerging WebAssembly ecosystem.

In this talk we will attempt to answer the following, based on our experience working Istio + WebAssembly in customer environments for over one year:

• How do we write WebAssembly filters?
• How do we test WebAssembly filters?
• How do we debug WebAssembly filters?
• How do we ship WebAssembly filters?

We will explore existing tooling and solutions for working with WebAssembly in the service mesh, and provide insight into the development processes being implemented by early adopters of WebAssembly.