# Overview (/docs/guides)



Each guide is a self-contained recipe. Start with the one that matches **where your code runs**.

## By runtime [#by-runtime]

| Guide                                                         | When to use                                                                                 |
| ------------------------------------------------------------- | ------------------------------------------------------------------------------------------- |
| [Filesystem (`loadConfig`)](/docs/guides/fs-loadconfig)       | Long-running Node/Bun/Deno server reading config files from disk.                           |
| [SPA — dynamic import](/docs/guides/spa-dynamic-import)       | Pure SPA built with Vite. Bundler emits one chunk per env; browser downloads the right one. |
| [SPA — Vite plugin (`#config`)](/docs/guides/spa-vite-plugin) | Pure SPA where you want each build artifact to contain **only** its env (max isolation).    |
| [SSR / SSG](/docs/guides/ssr)                                 | Server-rendered React app. Public values hydrate the browser via `<EnvScript />`.           |

## By task [#by-task]

| Guide                                                       | When to use                                                                          |
| ----------------------------------------------------------- | ------------------------------------------------------------------------------------ |
| [Schema composition](/docs/guides/schema-composition)       | Share a contract across server and client by inlining one `schema()` inside another. |
| [Custom modes (`staging`, `qa`)](/docs/guides/custom-modes) | Surface non-default Vite modes to browser code. Explains why the plugin is required. |

## How a guide is structured [#how-a-guide-is-structured]

Every guide follows the same shape:

1. **When to use it** — 1–2 bullets so you know whether to keep reading.
2. **Minimal working snippet** — copy-pasteable.
3. **What each piece does** — short explanation per moving part.
4. **Tradeoffs / limits** — when this recipe stops being a good fit.

Signatures and option tables live in the [API reference](/docs/api-reference), not in the guides.