Heroku for backend, automatically grow or shrink resources, nothing to maintain, nothing to configure and tons of services available alongside it.
Netlify for frontend, it is a static hosting service with some neat features like url rewriting that lets you proxy e.g. /api to a backend without revealing api keys and under the same origin / domain.
What really draws me to this is:
- no servers or software to maintain
- horizontal scaling by design (heroku kind of forces it)
- deploy process is "git push", fresh deploy is one click (heroku) and a few mins doing config on netlify though they have an api so maybe that's redundant
- no lock-in, easy to replicate locally
- databases are managed wrt backups, recovery etc
- entire front end is static and will scale indefinitely with massive uptime