Introduction to the Extension System

In an URN backend, we create modules that contain APIs.

These small modules build up your backend application.

They can be split into two categories:

Internal Modules

/src/app/internal

Internal modules are designed to load the built-in APIs.

Internal APIs will be overwritten if an external API has the same path and method.

External Modules

/src/app/external

These modules are designed to be extensions that overwrite the internal API, allowing developers to make modification easily.