Static site generation | SvelteKit 日本語

To use SvelteKit as a static site generator (SSG), use adapter-static.

This will prerender your entire site as a collection of static files. If you'd like to prerender only some pages and dynamically server-render others, you will need to use a different adapter together with the prerender option.

Usage

Run npx sv add sveltekit-adapter="adapter:static", or install with npm i -D @sveltejs/adapter-static and add the adapter to your vite.config.js:

vite.config.js

import adapter from '@sveltejs/adapter-static';
import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';

export default defineConfig({
	plugins: [
		sveltekit({
			adapter: adapter({
				// default options are shown. On some platforms
				// these options are set automatically — see below
				pages: 'build',
				assets: 'build',
				fallback: undefined,
				precompress: false,
				strict: true
			})
		})
	]
});

...and add the prerender option to your root layout:

src/routes/+layout.js

// If you're using a fallback (i.e. SPA mode) you don't need to prerender all
// pages by setting this here, but should prerender as many as possible to
// avoid large performance and SEO impacts
export const prerender = true;

Note

You must ensure SvelteKit's trailingSlash option is set appropriately for your environment. If your host does not render /a.html upon receiving a request for /a then you will need to set trailingSlash: 'always' in your root layout to create /a/index.html instead.

Note

You must ensure SvelteKit's ssr option isn't set to false. Otherwise, prerendering will save an empty 'shell' page instead of the fully rendered content.

Zero-config support

Some platforms have zero-config support (more to come in future):

Vercel

On these platforms, you should omit the adapter options so that adapter-static can provide the optimal configuration:

vite.config.js

import adapter from '@sveltejs/adapter-static';
import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';

export default defineConfig({
	plugins: [
		sveltekit({
			adapter: adapter({...})
		})
	]
});

Options

pages

The directory to write prerendered pages to. It defaults to build.

assets

The directory to write static assets (the contents of static, plus client-side JS and CSS generated by SvelteKit) to. Ordinarily this should be the same as pages, and it will default to whatever the value of pages is, but in rare circumstances you might need to output pages and assets to separate locations.

fallback

To create a single page app (SPA) you must specify the name of the fallback page to be generated by SvelteKit, which is used as the entry point for URLs that have not been prerendered. This is commonly 200.html, but can vary depending on your deployment platform. You should avoid index.html where possible to avoid conflicting with a prerendered homepage.

Note

This option has large negative performance and SEO impacts. It is only recommended in certain circumstances such as wrapping the site in a mobile app. See the single page apps documentation for more details and alternatives.

precompress

If true, precompresses files with brotli and gzip. This will generate .br and .gz files.

strict

By default, adapter-static checks that either all pages and endpoints (if any) of your app were prerendered, or you have the fallback option set. This check exists to prevent you from accidentally publishing an app where some parts of it are not accessible, because they are not contained in the final output. If you know this is ok (for example when a certain page only exists conditionally), you can set strict to false to turn off this check.

GitHub Pages

When building for GitHub Pages, if your repo name is not equivalent to your-username.github.io, make sure to update config.paths.base to match your repo name. This is because the site will be served from https://your-username.github.io/your-repo-name rather than from the root.

You'll also want to generate a fallback 404.html page to replace the default 404 page shown by GitHub Pages.

A config for GitHub Pages might look like the following:

vite.config.js

import process from 'node:process';
import adapter from '@sveltejs/adapter-static';
import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';

export default defineConfig({
	plugins: [
		sveltekit({
			adapter: adapter({
				fallback: '404.html'
			}),
			paths: {
				base: process.argv.includes('dev') ? '' : process.env.BASE_PATH
			},
		})
	]
});

You can use GitHub actions to automatically deploy your site to GitHub Pages when you make a change. Here's an example workflow:

.github/workflows/deploy.yml

name: Deploy to GitHub Pages

on:
  push:
    branches: 'main'

permissions:
  contents: read
  pages: read

concurrency:
  group: pages
  cancel-in-progress: false

jobs:
  build_site:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v7

      # If you're using pnpm, add this step then change the commands and cache key below to use `pnpm`
      # - name: Install pnpm
      #   uses: pnpm/action-setup@v6

      - name: Install Node.js
        uses: actions/setup-node@v7
        with:
          node-version: 24
          cache: npm

      - name: Install dependencies
        run: npm i

      - name: Configure Pages
        id: pages
        uses: actions/configure-pages@v6

      - name: build
        env:
          BASE_PATH: ${{ steps.pages.outputs.base_path }}
        run: |
          npm run build

      - name: Upload Artifacts
        uses: actions/upload-pages-artifact@v5
        with:
          # this should match the `pages` option in your adapter-static options
          path: 'build/'
          # keep dotfiles such as `static/.well-known`
          include-hidden-files: true

  deploy:
    needs: build_site
    runs-on: ubuntu-latest

    permissions:
      pages: write
      id-token: write

    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}

    steps:
      - name: Deploy
        id: deployment
        uses: actions/deploy-pages@v5

If you're not using GitHub actions to deploy your site (for example, you're pushing the built site to its own repo), add an empty .nojekyll file in your static directory to prevent Jekyll from interfering.