# FastifyViewOptions

**Kind:** Interface

**Source:** [`packages/platform-fastify/interfaces/external/fastify-view-options.interface.ts`](https://github.com/nestjs/nest/blob/master/packages/platform-fastify/interfaces/external/fastify-view-options.interface.ts#L6)

**Part of:** [Platform Fastify](subsystem-packages-platform-fastify)

"fastify/view" interfaces

`FastifyViewOptions` defines the configuration accepted by the Fastify view integration. It selects a template engine, identifies template locations, and configures rendering behavior such as layouts, caching, default context, and production settings.

## Properties

| Property | Type |
|---|---|
| `engine` | `{ ejs?: any; eta?: any; nunjucks?: any; pug?: any; handlebars?: any; mustache?: any; 'art-template'?: any; twig?: any; liquid?: any; dot?: any; }` |
| `templates` | `string | string[]` |
| `includeViewExtension` | `boolean` |
| `options` | `object` |
| `charset` | `string` |
| `maxCache` | `number` |
| `production` | `boolean` |
| `defaultContext` | `object` |
| `layout` | `string` |
| `root` | `string` |
| `viewExt` | `string` |
| `propertyName` | `string` |
| `asyncProperyName` | `string` |

## Diagram

```mermaid
graph LR
  A[FastifyViewOptions] --> B[engine]
  A --> C[templates / root]
  A --> D[Rendering options]
  A --> E[Cache and production settings]

  B --> B1[EJS]
  B --> B2[Eta]
  B --> B3[Nunjucks]
  B --> B4[Pug]
  B --> B5[Handlebars]
  B --> B6[Other supported engines]

  C --> C1[Template files or directories]
  D --> D1[layout]
  D --> D2[defaultContext]
  D --> D3[includeViewExtension]
  E --> E1[maxCache]
  E --> E2[production]
  E --> E3[charset]
```

## Usage

```ts
import fastify from 'fastify';
import fastifyView from '@fastify/view';
import ejs from 'ejs';
import type { FastifyViewOptions } from './interfaces/external/fastify-view-options.interface';

const app = fastify();

const viewOptions: FastifyViewOptions = {
  engine: {
    ejs,
  },
  root: `${process.cwd()}/views`,
  templates: `${process.cwd()}/views`,
  layout: 'layouts/main.ejs',
  includeViewExtension: true,
  production: process.env.NODE_ENV === 'production',
  maxCache: 100,
  charset: 'utf-8',
  defaultContext: {
    applicationName: 'My Fastify App',
  },
  options: {},
};

app.register(fastifyView, viewOptions);

app.get('/', async (_request, reply) => {
  return reply.view('index.ejs', {
    title: 'Home',
    message: 'Welcome!',
  });
});
```

## AI Coding Instructions

- Configure exactly one or more compatible engines under `engine`; ensure the corresponding template package is installed and imported.
- Use `root` and/or `templates` to point to valid template directories or files accessible at runtime.
- Keep `production` aligned with the deployment environment so template caching and reload behavior work as expected.
- Use `defaultContext` only for shared template data; pass request-specific values through `reply.view()` instead.
- When enabling `includeViewExtension`, consistently include template file extensions in view names and layout paths.