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

# Code Execution

> Run JavaScript and Python for analysis, transformation, and automation.

Navigator includes code execution so the assistant can calculate, transform data, prototype logic, and produce artifacts without leaving the chat.

<Frame>
  <img src="https://github.com/user-attachments/assets/7deed824-e70b-46d4-a294-de20ed4dc869" alt="Navigator JavaScript execution preview" />
</Frame>

## Execution backends

```dotenv theme={null}
NEXT_PUBLIC_CODE_EXECUTION_BACKEND=local
E2B_API_KEY=
```

Use the local browser worker for lightweight execution. Add E2B when you want server-side sandbox execution and richer preview flows.

## Typical tasks

<AccordionGroup>
  <Accordion title="Data cleanup" icon="table">
    Parse CSV, normalize fields, calculate totals, and produce clean tables.
  </Accordion>

  <Accordion title="Quick calculations" icon="calculator">
    Run exact arithmetic, statistics, conversions, and small simulations.
  </Accordion>

  <Accordion title="API payload shaping" icon="code">
    Transform JSON into the structure expected by an API, webhook, or workflow.
  </Accordion>

  <Accordion title="Chart preparation" icon="chart-line">
    Aggregate rows and prepare data for visualization tools.
  </Accordion>
</AccordionGroup>

<Warning>
  Do not expose server-only secrets to browser-visible code execution. Keep private keys in server-side environment variables.
</Warning>