OAuth2 — Nextcloud latest Administration Manual latest documentation
▻https://docs.nextcloud.com/server/19/admin_manual/configuration_server/oauth2.html
#Nextcloud allows connecting external services (for example Moodle) to your Nextcloud. This is done via #OAuth2. See RFC6749 for the OAuth2 specification.
Nextcloud OAuth2 implementation currently does not support scoped access. This means that every token has full access to the complete account including read and write permission to the stored files. It is essential to store the OAuth2 tokens in a safe way!
Without scopes and restrictable access it is not recommended to use a Nextcloud instance as a user authentication service.