I’m exploring how multi-tenant SaaS platforms (like Medium/Hashnode) handle custom domains.

Assume my application already supports multi-tenancy at the code level:

• Identify tenant using the Host header

• Map Host → tenant in DB

• Serve tenant-specific data/content

Now the infrastructure question:

Users will point their domains to my app using:

• A record → my IP, or

• CNAME → my endpoint

How can a single server/app accept requests from N number of custom domains without using a Load Balancer?

I know these common approaches:

1. Use a Load Balancer (but adds fixed monthly cost + traffic charges)

2. Use a Linux VM with Nginx reverse proxy (works, but then scaling/SSL becomes tricky)

I’ve also seen Cloudflare Tunnel, but I want to avoid it due to potential extra latency.

Platforms I’m evaluating:

• AWS Amplify

• DigitalOcean App Platform

• GCP Cloud Run

• Render