Fly.io

What it is

Fly.io runs Docker containers on VMs distributed across 30+ regions worldwide. Instead of deploying to one datacenter and hoping your CDN covers latency, Fly runs your actual app close to users. It's not a CDN — it's real compute at the edge.

Who it's for

• Apps where latency is a hard requirement (realtime, gaming, WebSockets, financial data)
• Teams who've hit Railway or Render's scaling ceiling
• Engineers comfortable with Docker and networking concepts
• Geographically distributed user bases

The good

True global compute. fly deploy and your app runs in the regions closest to your users. Auto-scaling across regions. This is the core feature and it works well.

Pricing that makes sense at scale. You pay for actual VM usage — no seat-based pricing, no opaque bandwidth tiers. At $50+/mo spend, Fly is typically cheaper than Railway Pro.

Excellent for stateful workloads. Persistent volumes, private networking, built-in Wireguard mesh. You can run databases, Redis, and long-running processes that Railway and Render make awkward.

fly.io/blog is legitimately the best infrastructure blog in the industry. They're thoughtful engineers and it shows in the product.

The bad

The learning curve is real. flyctl is powerful but has a lot of concepts to internalize: regions, machines, apps, volumes, private networking. Compared to Railway's "just push code," Fly requires you to think.

The free tier is confusing. There's a monthly allowance, but it's expressed in compute-hours, not dollars. Most developers get bitten by an unexpected bill.

Documentation has gaps. The reference docs are complete but scattered. Troubleshooting often means reading GitHub issues or Discord.

Support is community-first. Paid support tiers exist but are expensive. For a solo founder, you're mostly on your own.

Pricing reality

The free allowance covers 3 shared-cpu-1x VMs at 256MB RAM. Beyond that: ~$1.94/mo for the cheapest VM. For a typical backend + Postgres: ~$10-20/mo depending on scale. Cheaper than Railway at scale, harder to predict at first.

Verdict

Fly is the right choice when you need global distribution or have outgrown simpler PaaS options. It's not beginner-friendly and the pricing model takes getting used to. If your app serves users in multiple continents or you have strict latency requirements, nothing else competes at this price point.