feat: migrate from Jekyll to VitePress

.github/workflows/deploy.yml

@@ -0,0 +1,48 @@
+name: Deploy VitePress site to Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pages: write
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 20
+          cache: npm
+      - uses: actions/configure-pages@1f0c5cde4bc74cd7e1254d0cb4de8d49e9068c7d # v4
+      - run: npm ci
+      - run: npm run docs:build
+      - uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
+        with:
+          path: .vitepress/dist
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4

.gitignore

@@ -1,6 +1,4 @@
-_site
-.sass-cache
-.jekyll-metadata
+node_modules/
+.vitepress/dist/
+.vitepress/cache/
 .DS_Store
-.swp
-*~

.readthedocs.yml

@@ -1,20 +1,18 @@
-# .readthedocs.yml
 # Read the Docs configuration file
-# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+# See https://docs.readthedocs.com/platform/stable/build-customization.html
+# RTD configures the VitePress base URL automatically at build time.
 
-# Required
 version: 2
 
-# Set the version of Python and other tools you might need
 build:
-  os: ubuntu-24.04
-
+  os: ubuntu-lts-latest
   tools:
-    ruby: "3.4"
-
-  commands:
-    - bundle install
-    - >
-      JEKYLL_ENV=production bundle exec jekyll build --destination
-      _readthedocs/html --baseurl $(echo -n "$READTHEDOCS_CANONICAL_URL" | cut
-      -d '/' -f 4-)
+    nodejs: "latest"
+  jobs:
+    install:
+      - npm ci
+    build:
+      html:
+        - npm run docs:build
+        - mkdir -p $READTHEDOCS_OUTPUT/
+        - mv .vitepress/dist $READTHEDOCS_OUTPUT/html

.vitepress/config.mts

@@ -0,0 +1,100 @@
+import { defineConfig } from 'vitepress'
+import { redirectsPlugin, defaultPluginOptions } from './plugins/redirects'
+
+// Read the path prefix from RTD's canonical URL env var when present
+// (e.g. https://<slug>.readthedocs.build/en/171/ → /en/171/), so all
+// asset URLs resolve correctly under the PR-preview subpath. Defaults
+// to '/' for the GitHub Pages build at zarr.dev.
+const rtdUrl = process.env.READTHEDOCS_CANONICAL_URL
+const base = rtdUrl ? new URL(rtdUrl).pathname : '/'
+
+export default defineConfig({
+  base,
+  title: 'Zarr',
+  description: 'Zarr is a community project to develop specifications and software for storage of large N-dimensional typed arrays, also commonly known as tensors.',
+  cleanUrls: true,
+  lastUpdated: true,
+  sitemap: { hostname: 'https://zarr.dev' },
+  head: [
+    ['link', { rel: 'icon', type: 'image/x-icon', href: '/favicon.ico' }],
+    ['link', { rel: 'icon', type: 'image/png', sizes: '16x16', href: '/favicon-16x16.png' }],
+    ['link', { rel: 'icon', type: 'image/png', sizes: '32x32', href: '/favicon-32x32.png' }],
+    ['link', { rel: 'apple-touch-icon', sizes: '180x180', href: '/apple-touch-icon.png' }],
+    ['link', { rel: 'manifest', href: '/site.webmanifest' }],
+    ['link', { rel: 'mask-icon', href: '/safari-pinned-tab.svg', color: '#5bbad5' }],
+    ['meta', { name: 'apple-mobile-web-app-title', content: 'Zarr' }],
+    ['meta', { name: 'application-name', content: 'Zarr' }],
+    ['meta', { name: 'theme-color', content: '#ffffff' }],
+    ['meta', { property: 'og:type', content: 'website' }],
+    ['meta', { property: 'og:site_name', content: 'Zarr' }],
+    ['meta', { property: 'og:title', content: 'Zarr' }],
+    ['meta', { property: 'og:description', content: 'An open, community-driven format for storing large arrays in any key-value store, including cloud object storage.' }],
+    ['meta', { property: 'og:image', content: 'https://zarr.dev/android-chrome-512x512.png' }],
+    ['meta', { property: 'og:url', content: 'https://zarr.dev/' }],
+    ['meta', { name: 'twitter:card', content: 'summary' }],
+    ['meta', { name: 'twitter:title', content: 'Zarr' }],
+    ['meta', { name: 'twitter:description', content: 'An open, community-driven format for storing large arrays in any key-value store, including cloud object storage.' }],
+    ['meta', { name: 'twitter:image', content: 'https://zarr.dev/android-chrome-512x512.png' }],
+    ['script', { async: '', src: 'https://www.googletagmanager.com/gtag/js?id=G-BCRR9QE7Z0' }],
+    ['script', {}, `window.dataLayer = window.dataLayer || [];
+function gtag(){dataLayer.push(arguments);}
+gtag('js', new Date());
+gtag('config', 'G-BCRR9QE7Z0');`],
+  ],
+  srcExclude: [
+    'docs/**',
+    'README.md',
+    'NOTICE.md',
+  ],
+  vite: {
+    plugins: [redirectsPlugin(defaultPluginOptions(process.cwd()))],
+  },
+  themeConfig: {
+    logo: '/android-chrome-192x192.png',
+    search: { provider: 'local' },
+    nav: [
+      { text: 'Adopters', link: '/adopters' },
+      { text: 'Community', link: '/community' },
+      { text: 'Conventions', link: '/conventions' },
+      { text: 'Datasets', link: '/datasets' },
+      { text: 'Implementations', link: '/implementations' },
+      { text: 'Office Hours', link: '/office-hours' },
+      { text: 'Slides', link: '/slides' },
+      {
+        text: 'External',
+        items: [
+          { text: 'Blog', link: 'https://zarr.dev/blog/' },
+          { text: 'Specification', link: 'https://zarr-specs.readthedocs.io/' },
+          { text: 'ZEPs', link: 'https://zarr.dev/zeps/' },
+          { text: 'Documentation', link: 'https://zarr.readthedocs.io/en/stable/' },
+        ],
+      },
+    ],
+    socialLinks: [
+      {
+        icon: {
+          svg: '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 530"><path d="M135.72 44.03C202.216 93.951 273.74 195.17 300 249.49c26.262-54.316 97.782-155.54 164.28-205.46C512.26 8.009 590-19.862 590 68.825c0 17.712-10.155 148.79-16.111 170.07-20.703 73.984-96.144 92.854-163.25 81.433 117.3 19.964 147.14 86.092 82.697 152.22-122.39 125.59-175.91-31.511-189.63-71.766-2.514-7.38-3.69-10.832-3.708-7.896-.017-2.936-1.193.516-3.707 7.896-13.714 40.255-67.233 197.36-189.63 71.766-64.444-66.128-34.605-132.26 82.697-152.22-67.108 11.421-142.55-7.45-163.25-81.433C20.15 217.612 9.997 86.535 9.997 68.825c0-88.687 77.742-60.816 125.72-24.795z" fill="currentColor"/></svg>',
+        },
+        link: 'https://bsky.app/profile/zarr.dev',
+        ariaLabel: 'Bluesky',
+      },
+      { icon: 'mastodon', link: 'https://fosstodon.org/@zarr' },
+      { icon: 'github', link: 'https://github.com/zarr-developers' },
+      {
+        icon: {
+          svg: '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 2C6.48 2 2 6.48 2 12c0 1.81.49 3.51 1.34 4.97L2 22l5.16-1.35A9.95 9.95 0 0 0 12 22c5.52 0 10-4.48 10-10S17.52 2 12 2z" fill="currentColor"/></svg>',
+        },
+        link: 'https://ossci.zulipchat.com/',
+        ariaLabel: 'Zulip',
+      },
+    ],
+    editLink: {
+      pattern: 'https://github.com/zarr-developers/zarr-developers.github.io/edit/main/:path',
+      text: 'Edit this page on GitHub',
+    },
+    footer: {
+      message: 'Released under the MIT License.',
+      copyright: 'Copyright © Zarr contributors',
+    },
+  },
+})

.vitepress/plugins/redirects.ts

@@ -0,0 +1,102 @@
+import { readFileSync, mkdirSync, writeFileSync, existsSync } from 'node:fs'
+import { dirname, join, resolve } from 'node:path'
+import yaml from 'js-yaml'
+import type { Plugin } from 'vite'
+
+interface RedirectEntry {
+  from: string
+  to: string
+}
+
+const escapeHtml = (s: string): string =>
+  s.replace(/&/g, '&')
+   .replace(/"/g, '"')
+   .replace(/</g, '&lt;')
+   .replace(/>/g, '&gt;')
+
+const renderRedirectHtml = (to: string): string => {
+  const target = escapeHtml(to)
+  return `<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>Redirecting...</title>
+  <link rel="canonical" href="${target}">
+  <meta http-equiv="refresh" content="0; url=${target}">
+  <meta name="robots" content="noindex">
+</head>
+<body>
+  <p>Redirecting to <a href="${target}">${target}</a>...</p>
+  <script>location.replace("${target}")</script>
+</body>
+</html>
+`
+}
+
+const parseRedirectsYaml = (source: string): RedirectEntry[] => {
+  const parsed = yaml.load(source)
+  if (parsed === null || parsed === undefined) return []
+  if (typeof parsed !== 'object' || Array.isArray(parsed)) {
+    throw new Error('redirects.yml must be a YAML mapping at the top level')
+  }
+  const entries: RedirectEntry[] = []
+  for (const [from, to] of Object.entries(parsed as Record<string, unknown>)) {
+    if (typeof to !== 'string') {
+      throw new Error(`redirect target for "${from}" must be a string, got ${typeof to}`)
+    }
+    if (!from.startsWith('/')) {
+      throw new Error(`redirect source "${from}" must start with a leading slash`)
+    }
+    entries.push({ from, to })
+  }
+  return entries
+}
+
+const stripLeadingSlash = (p: string): string => (p.startsWith('/') ? p.slice(1) : p)
+const stripTrailingSlash = (p: string): string => (p.endsWith('/') ? p.slice(0, -1) : p)
+
+interface RedirectsPluginOptions {
+  yamlPath: string
+  outDir: string
+}
+
+export const redirectsPlugin = (options: RedirectsPluginOptions): Plugin => {
+  // VitePress emits both SSR and client bundles, so closeBundle fires twice.
+  // Only emit stubs on the first call.
+  let written = false
+  return {
+    name: 'zarr-redirects',
+    apply: 'build',
+    closeBundle() {
+      if (written) return
+      written = true
+
+      const yamlSource = readFileSync(options.yamlPath, 'utf8')
+      const entries = parseRedirectsYaml(yamlSource)
+
+      for (const { from, to } of entries) {
+        const cleaned = stripTrailingSlash(stripLeadingSlash(from))
+        const outPath = cleaned === ''
+          ? join(options.outDir, 'index.html')
+          : join(options.outDir, cleaned, 'index.html')
+
+        if (existsSync(outPath)) {
+          throw new Error(
+            `Redirect "${from}" collides with an existing build output at ${outPath}. ` +
+            `Either remove the redirect or rename the page that produced ${outPath}.`,
+          )
+        }
+
+        mkdirSync(dirname(outPath), { recursive: true })
+        writeFileSync(outPath, renderRedirectHtml(to), 'utf8')
+      }
+
+      console.log(`[zarr-redirects] wrote ${entries.length} redirect stubs`)
+    },
+  }
+}
+
+export const defaultPluginOptions = (rootDir: string): RedirectsPluginOptions => ({
+  yamlPath: resolve(rootDir, '.vitepress/redirects.yml'),
+  outDir: resolve(rootDir, '.vitepress/dist'),
+})

.vitepress/redirects.yml

@@ -0,0 +1,36 @@
+# Each entry maps a path on zarr.dev to an absolute or relative target URL.
+# A buildEnd hook turns this into static meta-refresh stub HTML files
+# under .vitepress/dist/<from>/index.html.
+
+# numcodecs codec docs (mirrors the deleted numcodecs_redirects/ verbatim)
+/numcodecs/adler32:          https://numcodecs.readthedocs.io/en/stable/checksum32.html#adler32
+/numcodecs/astype:           https://numcodecs.readthedocs.io/en/stable/astype.html
+/numcodecs/bitround:         https://numcodecs.readthedocs.io/en/stable/bitround.html
+/numcodecs/blosc:            https://numcodecs.readthedocs.io/en/stable/blosc.html
+/numcodecs/bz2:              https://numcodecs.readthedocs.io/en/stable/bz2.html
+/numcodecs/crc32:            https://numcodecs.readthedocs.io/en/stable/checksum32.html#crc32
+/numcodecs/delta:            https://numcodecs.readthedocs.io/en/stable/delta.html
+/numcodecs/fixedscaleoffset: https://numcodecs.readthedocs.io/en/stable/fixedscaleoffset.html
+/numcodecs/fletcher32:       https://numcodecs.readthedocs.io/en/stable/checksum32.html#fletcher32
+/numcodecs/gzip:             https://numcodecs.readthedocs.io/en/stable/gzip.html
+/numcodecs/jenkins_lookup3:  https://numcodecs.readthedocs.io/en/stable/checksum32.html#jenkinslookup3
+/numcodecs/lz4:              https://numcodecs.readthedocs.io/en/stable/lz4.html
+/numcodecs/lzma:             https://numcodecs.readthedocs.io/en/stable/lzma.html
+/numcodecs:                  https://numcodecs.readthedocs.io/en/stable/
+/numcodecs/packbits:         https://numcodecs.readthedocs.io/en/stable/packbits.html
+/numcodecs/pcodec:           https://numcodecs.readthedocs.io/en/stable/pcodec.html
+/numcodecs/quantize:         https://numcodecs.readthedocs.io/en/stable/quantize.html
+/numcodecs/shuffle:          https://numcodecs.readthedocs.io/en/stable/shuffle.html
+/numcodecs/zfpy:             https://numcodecs.readthedocs.io/en/stable/zfpy.html
+/numcodecs/zlib:             https://numcodecs.readthedocs.io/en/stable/zlib.html
+/numcodecs/zstd:             https://numcodecs.readthedocs.io/en/stable/zstd.html
+
+# URL hygiene: catch any external link to /office_hours/
+/office_hours/:              /office-hours/
+
+# Restored behavior of the deleted about/index.html stub
+/about:                      /
+
+# Vestigial 2019 blog posts -> blog repo
+/2019/05/02/zarr-2.3-release/: https://zarr.dev/blog/release-23/
+/2019/06/19/zarr-v3-update/:   https://zarr.dev/blog/v3-update/