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Box sizes

You get one box. Everything you deploy runs on it, and you can deploy as many apps as you like — that never costs extra. The only thing you ever choose is how much machine is underneath them.

Plan vCPU RAM Disk Good for
Starter 2 2 GB 20 GB Lots of small ideas at once
Builder 3 4 GB 20 GB A project starting to get real traffic
Pro 4 8 GB 20 GB Heavier apps, or several busy ones

Disk is the same on every plan — it's the CPU and memory that grow. Sizing up will not give you more space, so if you're running out of space rather than speed, a bigger plan isn't the fix; see disk is filling up.

Knowing when to move up

Your dashboard shows what the box is actually doing — CPU, memory, disk, and a short CPU history. That's the signal, and it's the honest one:

  • Memory near the top, consistently — the clearest reason to size up. When a box runs out of memory, Linux kills whichever container is using the most, which usually looks like an app mysteriously restarting. Before you size up, check it isn't a per-service limit instead — the default is a deliberately small 256 MB, which is far too little for Postgres or a JVM, and no amount of extra box RAM fixes that.
  • CPU pinned at 100% for long stretches — requests get slow. Brief spikes during a deploy or a build are normal and not worth acting on.
  • Disk above ~80% — a bigger plan won't help; the box already prunes old images weekly, so this is your data. See disk is filling up.

Overloading your box is allowed. It slows down; it doesn't get you a bill. That's the whole point of a fixed price.

Changing size

On your dashboard, pick a plan under Box size. That's it.

Here's what happens:

  1. Your subscription moves to the new price, and the difference is settled at the moment of the change — you only ever pay the difference, never a second full month. The exact mechanics, in both directions, are on the billing page.
  2. Your box restarts at the new size. It's offline for about a minute.
  3. Your apps come back automatically, along with everything on the disk.

Your data stays put

A resize is not a rebuild. The machine keeps its disk, so your apps, their databases, their volumes, and your box's TLS certificates all survive. Your box also keeps the same IP address, so nothing about your DNS changes.

If a resize doesn't complete — a cloud hiccup, say — your box keeps running at its old size and the dashboard offers you a Retry. It never leaves you stranded between two sizes. And if the payment for an upgrade doesn't go through, nothing happens at all: your plan stays where it was and your box isn't touched.

Moving back down

Downgrading works the same way, costs nothing to do, and comes back as credit against your next invoice rather than a refund.

The one thing to check first is memory. Your apps keep running and your data is untouched, but they'll have less RAM to share — and if they need more than the smaller box has, Linux starts killing containers, which shows up as apps mysteriously restarting. Look at the memory meter on your dashboard: if you're comfortably under the size you're dropping to, you're fine.

Picking a size at signup

Start with Starter. It's genuinely enough for a handful of small apps, and moving up later takes a minute of downtime and no migration work. Sizing up when you feel it beats guessing now — and unlike disk, it's a decision you can reverse.