Two hosts, one domain

The setup

sof.ai is deployed across two hosts:

• Frontend: Vercel, pulling from the repo's web/ directory. Auto-redeploys on every push to main.
• Backend: Fly.io, a single machine in iad region, SQLite on a persistent volume.
• Domain: sof.ai, registered on Namecheap. @ A record → Vercel (76.76.21.21). www CNAME → Vercel. api CNAME → Fly.

One domain, two hosts, no third-party reverse proxy.

Why not Vercel for both

Vercel is excellent at Next.js; we use it. It is not designed to run persistent processes with filesystem state. Fly is.

The backend stores challenges (and, soon, more) in SQLite. SQLite needs a persistent filesystem. Fly gives us that with a Volume. One 512MB shared VM in iad, one mounted volume at /data, DATABASE_URL = sqlite:////data/sof_ai.db.

If we outgrow SQLite, we migrate the Challenge model to Postgres. The model layer is already SQLModel, so the change is a config flip

• a migration. We intentionally didn't over-engineer past SQLite until we had users.

The deploy story in one paragraph

Dr. Freedom runs fly tokens create deploy -a sofai locally, pastes the token into Devin. Devin writes a Dockerfile (Python 3.12-slim

• uv + the FastAPI app), a fly.toml (single machine, volume mount, health check on /health), runs fly deploy. Thirty seconds later, curl https://sofai.fly.dev/health returns {"status":"ok"}.

Vercel is the same story with fewer steps. Frontend connects to the backend via NEXT_PUBLIC_API_BASE_URL, set to https://api.sof.ai.

The DNS reveal

On Namecheap Advanced DNS:

• A @ 76.76.21.21 → Vercel
• CNAME www cname.vercel-dns.com. → Vercel
• CNAME api sofai.fly.dev. → Fly

Three records. That's the entire glue.

What to internalize

Pick the smallest hosting setup that separates concerns by state.

• Stateless frontend → platform optimized for stateless frontends.
• Stateful backend → platform optimized for persistent state.
• Domain → the glue.

You do not need Kubernetes. You do not need a reverse proxy in front of it. You do not need a separate CDN config for the API subdomain. You need three DNS records.

Your turn

Write your own 3-record DNS plan for a project you're building or would like to build. Use the exact pattern:

• A @ <ip> → frontend host
• CNAME www <hostname> → same frontend host
• CNAME <service> <hostname> → backend host

Post it in the discussion. Optional: describe the state your backend holds and why it can't live in the frontend platform.

Next: the iteration loop after you go live. What Dr. Freedom and Devin actually do week-over-week with the challenges board.

Based on sof.ai's real production setup — Vercel for web/, Fly.io for api/, Namecheap DNS at the top. The fly.toml, Dockerfile, and rewrite config are all in the repo.