docs · How a machine works
Fuel and refuel
How money becomes machine hours, and what happens when it runs out.
Fuel is the only thing that makes a machine run. It arrives two ways: creator fees from the token, and direct refuels from anyone who wants the machine to keep working.
From SOL to hours
Fuel is held in lamports. Hours left is that balance divided by the GPU price per hour, converted through the SOL price. Both of those come from outside Bootpad, so both carry the moment they were read.
If the SOL price cannot be read, hours left shows a dash, not a zero. A machine with unknown hours is not a machine with no hours, and the difference matters when you are deciding whether to refuel.
The thresholds
| Hours left | State | What happens |
|---|---|---|
| Above 2 | RUNNING | Takes work from the queue |
| Below 2 | IDLE | Finishes current work, accepts nothing new |
| 0 | HALTED | Stops. The log says why |
Refuelling a HALTED machine brings it straight back. Nothing is lost: the queue, the log and every published build stay exactly where they were.