Fly.io Migration Guide: Move to HostStack

Fly.io gives you machines in 17 regions — five of them in Europe — and lets you build the platform on top. It is also a US company: Fly.io, Inc., under California law, so an Amsterdam or Frankfurt region does not change who can be compelled to hand data over. New organisations have had no free allowance since Fly retired its plans in October 2024, and Fly Managed Postgres starts at $38/mo plus storage. HostStack is the opposite trade: one EU region, an opinionated PaaS, and the database, backups, cron and workers run for you.

Why switch from Fly.io?

• An EU company on the contract: HostStack is operated by MICCI, a Danish company, with every service and database in Helsinki. Fly.io, Inc. is a US company, so the US CLOUD Act reaches it in every region it runs.
• Managed Postgres from €4/mo with storage and nightly backups included, and in-place major-version upgrades from the CLI or dashboard. Fly Managed Postgres starts at $38/mo plus $0.28/GB of storage, and Fly lists security patches and version upgrades as not there yet.
• A free tier that does not expire: 1 Nano service + 1 Starter Postgres + 1 cron + 1 preview env, no card. A new Fly organisation gets a trial of up to 2 machine-hours or 7 days, and needs a card on file.
• Deploys on every push from GitHub, GitLab, Bitbucket or Codeberg, with no CI workflow of your own to write.
• Managed MySQL, MariaDB, MongoDB and Redis next to Postgres on the same bill. On Fly, Redis is Upstash.
• No Dockerfile required: HostStack detects Node, Bun, Python, Ruby, Go, Rust, Java, PHP, .NET and Elixir and builds them itself — or builds the Dockerfile you already deploy to Fly.
• 200 GB/team of bandwidth included, then a flat 1¢/GB, invoiced in EUR with EU VAT.

Price comparison

Fly.io prices checked October 2026 against their public pricing page. Fly.io prices are USD as published; HostStack figures are the live EUR catalog. Verify at the source before deciding.

Code migration

# fly.toml
app = "my-app"
primary_region = "ams"

[build]
  dockerfile = "Dockerfile"

[env]
  NODE_ENV = "production"

[deploy]
  release_command = "npm run migrate"

[http_service]
  internal_port = 3000
  force_https = true
  auto_stop_machines = "stop"
  auto_start_machines = true
  min_machines_running = 0

[[mounts]]
  source = "data"
  destination = "/data"

# hoststack.yaml -- configures the existing "my-app" service
services:
  my-app:
    port: 3000
    env:
      NODE_ENV: production
    disk:
      name: data
      mountPath: /data
      sizeGB: 1

# Not in this file -- set on the service:
#   [build] dockerfile -> hoststack services update svc_... --dockerfile-path Dockerfile
#   release_command    -> hoststack services update svc_... --pre-deploy-command "npm run migrate"
#   Postgres           -> hoststack db create --project prj_... --name my-db --engine postgres --plan micro
#                         hoststack db link db_... --service svc_...

Feature comparison

Migration gotchas

Migration steps

1. 1Sign up at hoststack.dev — no card for the free tier — and connect GitHub, GitLab, Bitbucket or Codeberg.
2. 2Create a web service from the repo you deploy to Fly, without picking a runtime or commands, and HostStack builds the Dockerfile at its root. For a Dockerfile elsewhere, or a service that already exists, run hoststack services update svc_... --dockerfile-path <path>; without a Dockerfile, HostStack detects the runtime and builds it. Put fly.toml’s internal_port in hoststack.yaml as port — it becomes PORT in the container.
3. 3Recreate your secrets. fly secrets list shows names and digests, never values, so collect the values from where you keep them into a .env file and run hoststack env import svc_... .env. It is a dry run that lists what would change; add --apply to write. Non-secret [env] values go in hoststack.yaml.
4. 4Turn release_command into a pre-deploy command: hoststack services update svc_... --pre-deploy-command "npm run migrate".
5. 5Create a managed Postgres with hoststack db create and link it with hoststack db link, which injects DATABASE_URL. Dump the Fly database through a local tunnel — fly mpg proxy for Managed Postgres (it listens on localhost:16380), fly proxy 5432 -a <postgres-app> for the older unmanaged Fly Postgres — and restore the dump into the new database with external access turned on.
6. 6If the app keeps files on a Fly volume, pack them into a .tar.gz and upload it on the HostStack volume’s Storage tab.
7. 7Point DNS at HostStack once the deploy is live and the certificate is issued. Keep the Fly app running until traffic has moved, then destroy it.

Frequently asked questions