> ## Documentation Index
> Fetch the complete documentation index at: https://levers9.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Blueprint

> Demo: blueprint

Source: `demo/blueprint/app.py` in the repository.

What goes into the container: Python version, pip packages, system packages, files. Blueprints are built once
and cached; a function whose blueprint has not changed starts in seconds.

```bash theme={null}
cd demo/blueprint

# first run builds the blueprint (watch the build log), later runs reuse it
python app.py
# {"python": "3.11.x", "numpy": "2.1.3", "pandas": "2.2.3", "jq": "jq-1.6", "sum_y": 30}
```

Notes

* `Blueprint(python_version=..., python_packages=[...])` for pip packages; pin versions for reproducible builds.
* `.add_commands([...])` runs shell commands at build time: apt packages, downloads, baking files.
* `Blueprint(base_image="...")` starts from any public or private Docker image (see `Blueprint` docs for
  registry credentials via secrets).
* One blueprint can be shared by many functions; put it in a module and import it.


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