Hey @freek-gcompany,
This is correct - the reason for this is the way that the SDK is currently built out. Custom views / widgets can be uploaded to monday as it is code which will run on things like dashboards.
Custom integrations however require an external server as monday is essentially acting as a trigger to notify your app on things like a column being changed.
Right now there isn’t a way to host the endpoint on the monday.com infrastructure, however I’ll be glad to pass the feedback along. We do have a community post you can refer to in terms of best practices and authorization for widgets and views.
-Daniel