Apps are custom external applications that you link to from the Crystallize PIM user interface via a URL. If we don’t offer some functionality that you need, you can build it yourself or find it elsewhere and allow your tenant’s users to access it within our UI. An example of this might be import and export tools designed for your specific business needs. Read more about adding Apps to your tenant.
Apps are not plug-ins or mods. They don't touch our code at all, and can’t be used to modify the PIM UI.
The requests that Crystallize sends to your App are signed such that your App can be configured to verify the signatures.