---
description: Learn how the Sandbox SDK works, including architecture, lifecycle, security, and sessions.
title: Concepts
image: https://developers.cloudflare.com/og-docs.png
---

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

# Concepts

Last updated Sep 1, 2026|Copy as Markdown| [View as Markdown](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/index.md)| [Agent setup](https://0285ca83.previews.developers.cloudflare.com/agent-setup/)

These pages explain how the Sandbox SDK works, why it's designed the way it is, and the concepts you need to understand to use it effectively.

- [Architecture](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/architecture/) - How the SDK is structured and why
- [Sandbox lifecycle](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/sandboxes/) - Understanding sandbox states and behavior
- [Container runtime](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/containers/) - How code executes in isolated containers
- [Session management](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/sessions/) - When and how to use sessions
- [Preview URLs](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/preview-urls/) - How to expose sandboxed services on the public internet.
- [Security model](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/security/) - Isolation, validation, and safety mechanisms
- [Terminal connections](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/terminal/) - How browser terminal connections work
- [Directory backups](https://0285ca83.previews.developers.cloudflare.com/sandbox/concepts/backup-restore/) - Overlay restore, local extract, and cross-device renames

## Related resources

- [Tutorials](https://0285ca83.previews.developers.cloudflare.com/sandbox/tutorials/) - Learn by building complete applications
- [How-to guides](https://0285ca83.previews.developers.cloudflare.com/sandbox/guides/) - Solve specific problems
- [API reference](https://0285ca83.previews.developers.cloudflare.com/sandbox/api/) - Technical details and method signatures

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