Running untrusted third party code is not a good idea. It is also really useful. In a browser we do that literally all the time, but on our servers we are much more hesitant. That is where sandboxing comes in. Sandboxing allows us to run code and only let it touch what we want it to touch. For this we will be looking at Web Assembly, a promising binary form, born on the web, to use in our services. We’ll have a look at Extism, a framework that lets us integrate web assembly into our Java codebase with ease.