Fly.io
Deploy apps to edge locations near your users with Docker
What it does
Fly.io is a global application-hosting platform that runs Docker containers as lightweight VMs (Firecracker) across 35+ regions worldwide. Deploy via CLI (fly deploy), get an app running near your users with automatic edge routing. Attach Postgres (Fly Postgres, self-managed), Redis (Upstash on Fly), object storage (Tigris), and use Fly Machines (per-second billing containers) for background workers or ephemeral compute. Positioned as "put your app close to users."
Free tier
Yes
Setup
medium
Key features
Integrates with
Docker, GitHub Actions
Who this fits
- Developers building latency-sensitive apps that benefit from multi-region deploy
- Bootstrapped SaaS teams that want a modern PaaS without AWS complexity
- Full-stack developers who want fly deploy and be done
- Teams building AI apps (Fly's GPU offering supports LLM inference and training)
- Anyone shipping Elixir Phoenix apps (Fly was born from that ecosystem; deep support)
Who it does NOT fit
- Teams needing managed compliance (HIPAA BAA, SOC 2 depth Fly still ramps)
- Enterprises requiring AWS/GCP ecosystem services (RDS, Redshift, SQS, Cognito)
- Non-technical users; Fly is developer-first
- Static sites with no server (use Netlify or Vercel for those; Fly is overkill)
Pricing
Real gotchas
- The free tier was killed September 2024. Old accounts with the "3 free VMs" baseline had to migrate; new accounts pay from cent one (with $5/month hobby credit on most plans that offsets small workloads) [source: community.fly.io announcement, fly.io/blog/tightening-our-belts].
- Fly Postgres is "you run it, we help." Backups, HA, and upgrades are your responsibility unless you use the paid managed tier. Compare to RDS or Supabase where the operator handles it.
- Fly had multiple platform incidents and capacity issues in 2023-2024 that hit users hard. Reliability has improved but is not AWS-tier yet.
- Multi-region deploys require your app to handle write-after-read consistency (leader/replica routing); not automatic.
- IPv4 addresses cost $2/month per dedicated IPv4 (shared IPv4 is free); accidentally allocating multiple adds up.
Integrations that matter
Otto’s take on this tool
Recommend Fly.io for developers building latency-sensitive apps, multi-region SaaS, or full-stack apps that outgrew Heroku or Render. Recommend Vercel or Netlify for frontend-heavy Next.js apps. Recommend Railway for simpler PaaS with a friendlier free-ish tier. Recommend Hetzner for bare-metal cost efficiency, or AWS/GCP when the client needs managed services.
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