Some API keys should be able to die. The contractor's engagement ends, the workshop wraps, the demo booth closes — and yet the key lives on in a dotfile somewhere, attached to your real bill. Burnable prepaid keys fix the incentive: the key is the budget.
How they work
Create a key with a fixed credit balance ($10, $200, whatever the engagement warrants) and an optional expiry date. It behaves like any other SwitchGate key — full catalog, model locks, tracing — until the balance hits zero or the date passes, at which point it stops. No invoice surprise is possible because the money was fenced before the first token moved.
Where they shine
Contractors: hand a key with the project budget; revoke nothing when they leave, because there's nothing left to revoke. Classrooms: a hundred students, $5 each, one CSV export for the department. Hackathons: print keys on badges — the failure mode is a student runs out, not a sponsor overpays. Demos: ship a key inside a trial build knowing its blast radius exactly.
Burnable keys count against your organization's budgets and appear on the same ledger, tagged by key, so the accounting stays one report. They're available today on every plan; unused prepaid balances return to your org when a key is burned early.