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

# Extensions

> Understand how extensions add focused capabilities to Veryfront.

Extensions are factories that add focused capabilities to a Veryfront project:
a cache store, an auth provider, a database adapter, a model provider, or an
MDX content pipeline.

For the concepts behind factories, contracts, capabilities, setup, and teardown,
see [Framework extensions](/code/concepts/framework-extensions).

## Prerequisites

* A Veryfront project with `veryfront.config.ts`.
* For a first-party extension: the matching package installed.
* For a local extension: a folder under `extensions/` with a default-exported
  factory (see [Extension authoring](/code/guides/extension-authoring)).

## Enable an extension

Add extension factories to `veryfront.config.ts`:

```ts theme={null}
import { defineConfig } from "veryfront";
import extRedis from "@veryfront/ext-cache-redis";

export default defineConfig({
  extensions: [
    extRedis({ url: "redis://localhost:6379", prefix: "myapp:" }),
  ],
});
```

Use a local extension the same way:

```ts theme={null}
import { defineConfig } from "veryfront";
import memoryCache from "./extensions/memory-cache/src/index.ts";

export default defineConfig({
  extensions: [
    memoryCache({ maxSize: 500 }),
  ],
});
```

Verify the extension loads by running the dev server:

```bash theme={null}
veryfront dev
```

If the extension factory throws during setup, the dev server reports the setup error. For local extensions, edit the extension source and save `veryfront.config.ts` to force reload during development.

## First-party extension areas

| Area          | Example package                              | Contract family   |
| ------------- | -------------------------------------------- | ----------------- |
| Auth          | `@veryfront/ext-auth-jwt`                    | `AuthProvider`    |
| Cache         | `@veryfront/ext-cache-redis`                 | `CacheStore`      |
| Content       | `@veryfront/ext-content-mdx`                 | content parsing   |
| CSS           | `@veryfront/ext-css-tailwind`                | CSS processing    |
| Database      | `@veryfront/ext-db-sqlite`                   | database access   |
| LLM           | `@veryfront/ext-llm-openai`                  | model providers   |
| Observability | `@veryfront/ext-observability-opentelemetry` | telemetry         |
| Parser        | `@veryfront/ext-parser-babel`                | parsing           |
| Sandbox       | `@veryfront/ext-sandbox-shell-tools`         | sandbox tools     |
| Schema        | `@veryfront/ext-schema-zod`                  | schema validation |

## Verify it worked

Restart `veryfront dev` after editing `veryfront.config.ts`:

* The dev log should print a setup line for each loaded extension.
* Any contract the extension provides should now be resolvable through the
  matching consumer (for example, a `CacheStore` extension lets cache-aware
  code skip its local fallback).
* If the factory throws during setup, the dev server prints the setup error
  with the extension name. Fix the error and reload.