RDS, it's more expensive but I'd rather not have to manage my own DB. I wrote about how I came to the decision here in case you're curious: https://onlineornot.com/self-hosting-vs-managed-services-dec...

I run two platforms/websites (SaaSHub & LibHunt) that both have 1M+ visits per month.

Both products run everything on a single $60 VPS (Linode dedicated CPU 8GB). That includes Ruby on Rails, background queues, Redis (cache and queues) and of course, Postgres. On both machines Postgres takes about 1.3G RAM and not too much of the CPU. CPU utilization is 37% avg and 13% avg.

So, yeah, I don't think you need managed and "scalable" Postgres provisioning in most of the cases.

Hosted Postgres on digital ocean, I use Hetzner bare metal for all other services but Postgres is the one thing I use managed services for, why? I simply don’t know enough about Postgres to trust I’ll get everything resilient, backed up and secured correctly, although I guess when costs exceed managed features I’ll make the time to learn the above and host on bare metal.

We're using RDS mostly, though for some older services we have Postgres running on EC2 instances. I'd not recommend it unless you have some good infra people though, since all our EC2 ones are running old distros and old versions of Postgres because... nobody owned the upgrading of that.

For production I usually use the databases of my customers or employers. In my case that is most often a self-hosted on-premise server. More often MSSQL than Postgres, but the latter is getting more popular. For myself and development purposes I host it myself on a rented server.

Self hosted.

I pay about 40 Eur (Hetzner) per database server. You can get cheaper; I used to pay 50 usd for 2 database nodes with backup at digitalocean.

A little one at Digital Ocean.