# Choosing Where to Run Code
source: https://docs.chalk.ai/docs/compute/overview

## Choose between a Sandbox, a Scaling Group, and a Function for a workload you run on Chalk.

### Overview

Every workload you run on Chalk takes one of three shapes:

- Sandbox: an isolated environment for a single ephemeral task, torn down when the task finishes.
- ScalingGroup: a replicated, HTTP-fronted service that stays running and autoscales.
- Function: a Python callable, deployed once and invoked remotely.

All three take the same runtime environment settings: an image,
CPU, memory and GPU resources,
environment variables and secrets, and volumes.

### Choosing the right component

| Mental Model                          | Reach For                                      | Example                                                                                                                                                |
| ------------------------------------- | ---------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **An ephemeral task**                 | [`Sandbox`](/docs/compute/sandbox)             | Run an agent's generated code, a one-off data backfill, or a per-session agent workspace that is torn down when the session ends                       |
| **An application that lives forever** | [`ScalingGroup`](/docs/compute/scaling-groups) | A vLLM inference server, an internal API, a persistent agent or chat backend, or a hosted MCP server                                                   |
| **A (potentially long) RPC call**     | [`Function`](/docs/compute/functions)          | An embedding or re-ranking endpoint, an enrichment call inside a resolver, or a "score this transaction" call that returns a float to the query server |

A Sandbox is an ephemeral task. Reach for a sandbox
by default. For a long-running process that needs to be reachable over HTTP,
use a Scaling Group.

A Function deploys your callable onto a Scaling Group and registers it in the
Chalk Catalog. Use a Function when the workload needs to be reachable from Chalk
SQL, a resolver, the query server, or a DataFrame, or when it needs async
invocation, streaming results, nested calls, retries, concurrency caps, rate
limits, or request-queue-driven autoscaling.

The diagram below shows how these components sit inside a Chalk-managed
deployment in your cloud account. Sandboxes and scaling groups run on a
gVisor-hardened nodepool; image builds, the function registry, secrets, and
volumes are all reachable from the same VPC; clients can hit the API Server
directly, the Envoy router for HTTP traffic into a scaling group, or the
Function Queue for async invocations.

Chalk deployment architecture