Billing Model

Credits are debited from runtime periods while instances stay active.

• Usage charging is idempotent and safe to retry.
• Duplicate Cloud Tasks deliveries do not double-charge.
• At zero balance, the account is suspended and active instances are queued to stop.
• After refill, suspended instances can be auto-started.

Billing is scheduler-driven and stateless:

1. Cloud Scheduler calls billing fanout every minute.
2. Fanout enqueues shard tasks in Cloud Tasks.
3. Each shard task calls billing process for its shard.