Checkout pocketbase faq section for mode details
https://pocketbase.io/faq/
Pocketbase is a single server, aka. vertical. Most of the time, you may not need the complexity of managing a fleet of machines and services just to run your backend.
PocketBase is a great choice for small and midsize applications - SaaS, mobile api backend, intranet, etc.
Even without optimizations, PocketBase can easily serve 10 000+ concurrent and persistent realtime connections on a cheap $6 VPS (Hetzner 2vCPU, 4GB RAM).
Currently the following OAuth2 providers are supported - Google, Facebook, GitHub, GitLab (and more are coming).
PocketBase provides only SDKs for client-side integration and you are free to implement your own frontend.
For convenience, there are default user facing pages for the user email confirmation links (password reset, verification, etc.) but you can also set your own by updating the urls in the Admin UI settings.
PocketBase uses embedded SQLite (in WAL mode) and there are no plans for supporting other databases.