I'm looking for a webcam which is able to upload directly to a user-specified remote server - or which can be directly accessed remotely - without involving any kind of third party server or service such as a cloud hosting provider or a PC/Raspberry Pi/etc.
Ideally the webcam would run (open source) software which lets you specify a remote server (e.g. SFTP) to periodically upload images to, and would upload them directly from the camera itself straight to the server.
Alternatively the camera itself would run a small web server and accept incoming network requests (with strong authentication) from clients wishing to stream footage.
The camera should be wireless (e.g. at least WiFi but ideally 3G/4G cellular connection as a fallback) but a power cable is acceptable.
The only other piece of hardware involved should be a router to provide a WiFi signal (unless the camera also supports cellular connections).
The camera should not make any connections to any other servers except the user-specified one(s).