--- description: > Learn here about intrinsic capabilities to extend your applications in verticalization and customization scenarios. uacp: Used as link target from Help Portal at https://help.sap.com/products/BTP/65de2977205c403bbc107264b8eccf4b/e4a7559baf9f4e4394302442745edcd9.html --- # Extensibility {{ $frontmatter.description }} Extensibility of CAP applications is greatly fueled by **CDS Aspects**, which allow to easily extend existing models with new fields, entities, relationships, or new or overridden annotations [→ Learn more about using CDS Aspects in the Domain Modeling guide](../domain/index#separation-of-concerns). ![This screenshot is explained in the accompanying text.](assets/extensibility.drawio.svg) As illustrated in the graphic above, different parties can build and deploy CDS Aspects-based extensions: - **Customizations** – Customers/Subscribers of SaaS solutions need options to tailor these to their needs, again using CDS Aspects to add custom fields and entities. - **Toggled Features** – SaaS providers can offer pre-built enhancement features, which can be switched on selectively per tenant using Feature Toggles, for example, specialization for selected industries. - **Composition** – Finally, 3rd parties can provide pre-built extension packages for reuse, which customers can pick and compose into own solutions. - **Verticalization** – 3rd parties can provide verticalized versions of a given base application, which they can in turn operate as verticalized SaaS apps.
The following guides give detailed information to each of these options.