Container Billing (CUS)

Container tasks are billed using Compute Unit Seconds (CUS), a metric that combines wall-clock time with container size.

What Are Compute Unit Seconds (CUS)

CUS measure container resource usage for billing. The formula:

CUS = ceil(wall_clock_seconds × size_multiplier)

• wall_clock_seconds — Actual execution time
• size_multiplier — Multiplier from the container size preset
• ceil — Rounds up (e.g. 0.5 seconds at 1x = 1 CUS)

A 10-second run at small (1.0x) consumes 10 CUS. The same run at nano (0.25x) consumes 3 CUS.

CUS Multiplier by Size

Get multipliers programmatically with ::hot::box/sizes():

all-sizes ::hot::box/sizes()
// [{name: "nano", memory-mb: 64, cus-multiplier: 0.25, ...}, ...]

Included CUS per Plan

Overage

Usage beyond included CUS is handled by plan:

• Free plan — Hard cap. When CUS are exhausted, new container tasks are blocked until the next billing period.
• Paid plans (Starter, Pro, Scale) — Overage is billed at the per-CUS rate on your next invoice.

Org Budget

Organizations can set an optional spending cap (compute_units_budget). When reached, container tasks are hard-blocked regardless of plan. This prevents unexpected overage charges.

Checking Quota

Use ::hot::box/quota() to check remaining CUS before starting containers:

q ::hot::box/quota()
q.compute-units-remaining   // CUS left this period (-1 = unlimited)
q.compute-units-used       // CUS consumed this period
q.tasks-remaining          // Tasks left (-1 = unlimited, 0 = exhausted)
q.overage                  // true if usage exceeds included (paid plans)

Example: check quota before running a container:

q ::hot::box/quota()
if(eq(q.tasks-remaining, 0), fail("No container tasks remaining"), "OK")
if(or(eq(q.compute-units-remaining, -1), gt(q.compute-units-remaining, 0)),
  ::hot::box/start(BoxConf({image: "alpine", cmd: ["echo", "hello"], size: "nano"})),
  fail("CUS quota exhausted"))