> ## Documentation Index
> Fetch the complete documentation index at: https://docs.continuouslabs.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Simulations

> Run one Simulator with isolated and repeatable state.

A Simulation is a runtime instance of one ready Simulator.
It has isolated state, a virtual clock, and a data-plane endpoint.

## Create a repeatable run

```bash theme={null}
continuous simulation create \
  --simulator billing:latest \
  --seed repeatable-run \
  --clock-start 2026-01-01T00:00:00Z
```

The seed and clock start pin injected randomness and virtual time.
Use the same Simulator revision and inputs when you need repeatable behavior.

The create response includes a data-plane token once.
List and get operations never return that token again.

## Control the lifecycle

Stop a Simulation to freeze its state.
Start it later to continue from that state.

```bash theme={null}
continuous simulation stop <simulation-id>
continuous simulation start <simulation-id>
```

Fork a running Simulation to explore another path without changing the source.
You can fork the current head or a recorded step.

```bash theme={null}
continuous simulation steps <simulation-id>
continuous simulation fork <simulation-id> --at-step <step>
```

Use the [API reference](/api-reference/overview) for exact Simulation routes and schemas.

<Columns cols={2}>
  <Card title="Choose a Simulator" icon="box" href="/concepts/simulators">
    Select the behavior that the Simulation runs.
  </Card>

  <Card title="Connect Simulations" icon="network" href="/concepts/worlds">
    Start related systems as one World.
  </Card>
</Columns>