Minimum
1GB RAM is enough for a static site plus a light API.
Pure static sites usually do not need a VPS. A VPS starts to make sense when the site also needs an API, reverse proxy, background jobs, or full server control.
1GB RAM is enough for a static site plus a light API.
1-2 vCPU / 1-2GB RAM / 25GB+ SSD for a small production stack.
Upgrade when API traffic, build jobs, analytics, or a database moves onto the same VPS.
The frontend is rarely the problem. The API, database, logs, deploy process, and SSL termination are what decide whether a VPS is the right tool.
Use static hosting when there is no server code. Use a 1GB or 2GB VPS when the static site is only the visible part of a small app.