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

# Introduction

> Infrastructure for agentic engineering. Building with agents is fast, and deploying with LazyCloud is too.

A decorator on your Python function names the packages, CPU, memory, GPU, and
storage it needs, so whoever writes the function, you or an agent, also writes
where it runs. LazyCloud builds the container, runs it on cloud CPUs and GPUs,
and stops it when the work is done. You pay per second while it runs. A
[coding agent](https://docs.lazycloud.dev/getting-started/agents.md) can do all of this from your machine
or from a devbox.

```python theme={null}
from lazycloud import App, Image
from pydantic import BaseModel

app = App("reports")


class Summary(BaseModel):
    total: float
    mean: float


@app.function(image=Image(python_version="3.12"), cpu=2, memory="4Gi")
def summarize(amounts: list[float]) -> Summary:
    return Summary(total=sum(amounts), mean=sum(amounts) / len(amounts))
```

## Develop locally, test in the cloud, deploy

The same file runs at every stage:

```bash theme={null}
uv run pytest                                           # tests call summarize.local(...)
uv run lazycloud run reports:summarize '[12.5, 30, 8]'   # run once in the cloud
uv run lazycloud deploy reports                         # keep it running in the cloud
```

No step opens a browser or prompts. With `--json` the result is one JSON
document on stdout, logs go to stderr, and a failure exits nonzero, so an agent
can run the loop and read the outcome.

## What you can ship

* [APIs](https://docs.lazycloud.dev/concepts/endpoints.md): a function as an HTTPS endpoint, or a full
  FastAPI app.
* [Jobs](https://docs.lazycloud.dev/concepts/functions.md): tests, evals, data processing, and GPU work
  fanned out across containers.
* [Background work and crons](https://docs.lazycloud.dev/concepts/schedules.md): tasks with retries,
  cancellation, and live logs.
* [Agent sandboxes](https://docs.lazycloud.dev/concepts/sandboxes.md): isolated containers for running your
  agent's code and tests.
* [Devboxes](https://docs.lazycloud.dev/concepts/dev-machines.md): SSH machines whose disk keeps your files.

## Next steps

* [Quickstart](https://docs.lazycloud.dev/getting-started/quickstart.md): develop, test, and deploy a
  first workload.
* [Apps and workloads](https://docs.lazycloud.dev/concepts/apps.md): the workload kinds and how an app
  groups them.
* [Examples](https://docs.lazycloud.dev/examples/index.md): GPU inference, training, document processing,
  and a sandboxed coding agent.


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