Fix SEO indexing: hreflang, canonicals, sitemap, trailing slash (#2193)

* Fix SEO indexing: add hreflang, canonicals, sitemap per-locale entries

Google Search Console showed 380 not-indexed vs 86 indexed pages.
Root causes: missing hreflang tags on rendered pages (only in sitemap),
no canonical on homepage, inconsistent canonicals wiping parent hreflang,
sitemap only listing English URLs, trailing slash duplicates, and
_next/static chunks being crawled as pages.

Changes:
- Add buildAlternates() utility for consistent canonical + hreflang
- Add hreflang tags to all pages via alternates.languages in metadata
- Add self-referencing canonical URLs to every page (homepage had none)
- Expand sitemap to emit separate entries for each locale
- Add missing /docs/custom-commands to sitemap
- Remove skipTrailingSlashRedirect to normalize trailing slashes
- Block /_next/ in robots.txt to stop chunk crawling

* Add per-page alternates to docs sub-pages and blog index

Docs sub-pages and blog index only returned title/description in
generateMetadata, so they inherited the parent layout's alternates
(pointing to /docs or /blog). Now each page sets its own
buildAlternates() with the correct path so canonical and hreflang
point to the actual page URL.

* Derive openGraph.url from buildAlternates to avoid drift

* Redirect non-English legal pages to English, remove from sitemap

Legal pages (privacy policy, TOS, EULA) are untranslated English content.
Serving them under every locale creates 54 duplicate URLs. Now:
- Middleware 301-redirects /ja/privacy-policy etc. to /privacy-policy
- Sitemap only includes English URLs for legal pages (no locale variants)
- Legal page metadata uses static English-only canonical

* Fix legal page redirect to only match /<locale>/<page> paths

endsWith matched too broadly (e.g. /docs/eula). Now only redirects
when the path after the first segment is an exact legal page match.

* Skip next-intl for legal pages to prevent locale redirect loop

Without this, a Japanese user hitting /privacy-policy could be
redirected by next-intl to /ja/privacy-policy, which our middleware
redirects back to /privacy-policy, creating a loop.

* Rewrite legal pages to /en/ instead of NextResponse.next()

Pages live under app/[locale]/, so skipping next-intl entirely
would break route resolution. Rewrite to /en/privacy-policy etc.
so Next.js can resolve the [locale] segment correctly.

---------

Co-authored-by: Lawrence Chen <lawrencecchen@users.noreply.github.com>

web/app/[locale]/(legal)/eula/page.tsx

@@ -3,7 +3,7 @@ import type { Metadata } from "next";
 export const metadata: Metadata = {
   title: "EULA — cmux",
   description: "End-User License Agreement for cmux",
-  alternates: { canonical: "./" },
+  alternates: { canonical: "https://cmux.com/eula" },
 };
 
 export default function EulaPage() {

web/app/[locale]/(legal)/privacy-policy/page.tsx

@@ -4,7 +4,7 @@ import { Link } from "../../../../i18n/navigation";
 export const metadata: Metadata = {
   title: "Privacy Policy — cmux",
   description: "Privacy policy for cmux",
-  alternates: { canonical: "./" },
+  alternates: { canonical: "https://cmux.com/privacy-policy" },
 };
 
 export default function PrivacyPolicyPage() {

web/app/[locale]/(legal)/terms-of-service/page.tsx

@@ -3,7 +3,7 @@ import type { Metadata } from "next";
 export const metadata: Metadata = {
   title: "Terms of Service — cmux",
   description: "Terms of service for cmux",
-  alternates: { canonical: "./" },
+  alternates: { canonical: "https://cmux.com/terms-of-service" },
 };
 
 export default function TermsOfServicePage() {

web/app/[locale]/blog/cmd-shift-u/page.tsx

@@ -1,11 +1,11 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { Link } from "../../../../i18n/navigation";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
   const { locale } = await params;
   const t = await getTranslations({ locale, namespace: "blog.cmdShiftU" });
-  const url = locale === "en" ? "/blog/cmd-shift-u" : `/${locale}/blog/cmd-shift-u`;
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
@@ -18,14 +18,13 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
       description: t("metaDescription"),
       type: "article",
       publishedTime: "2026-03-04T00:00:00Z",
-      url,
     },
     twitter: {
       card: "summary_large_image",
       title: t("metaTitle"),
       description: t("metaDescription"),
     },
-    alternates: { canonical: url },
+    alternates: buildAlternates(locale, "/blog/cmd-shift-u"),
   };
 }
 

web/app/[locale]/blog/introducing-cmux/page.tsx

@@ -1,11 +1,11 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { Link } from "../../../../i18n/navigation";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
   const { locale } = await params;
   const t = await getTranslations({ locale, namespace: "blog.introducingCmux" });
-  const url = locale === "en" ? "/blog/introducing-cmux" : `/${locale}/blog/introducing-cmux`;
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
@@ -18,14 +18,13 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
       description: t("metaDescription"),
       type: "article",
       publishedTime: "2026-02-12T00:00:00Z",
-      url,
     },
     twitter: {
       card: "summary_large_image",
       title: t("metaTitle"),
       description: t("metaDescription"),
     },
-    alternates: { canonical: url },
+    alternates: buildAlternates(locale, "/blog/introducing-cmux"),
   };
 }
 

web/app/[locale]/blog/layout.tsx

@@ -1,4 +1,5 @@
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { SiteHeader } from "../components/site-header";
 import { BlogPager } from "../components/blog-pager";
 import { BlogCTA } from "../components/blog-cta";
@@ -19,9 +20,7 @@ export async function generateMetadata({
       siteName: "cmux",
       type: "article" as const,
     },
-    alternates: {
-      canonical: "./",
-    },
+    alternates: buildAlternates(locale, "/blog"),
   };
 }
 

web/app/[locale]/blog/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { Link } from "../../../i18n/navigation";
 
 export async function generateMetadata({
@@ -12,6 +13,7 @@ export async function generateMetadata({
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/blog"),
   };
 }
 

web/app/[locale]/blog/show-hn-launch/page.tsx

@@ -1,6 +1,7 @@
 import Image from "next/image";
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { Link } from "../../../../i18n/navigation";
 import { Tweet } from "react-tweet";
 import starHistory from "./star-history.png";
@@ -8,7 +9,6 @@ import starHistory from "./star-history.png";
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
   const { locale } = await params;
   const t = await getTranslations({ locale, namespace: "blog.showHnLaunch" });
-  const url = locale === "en" ? "/blog/show-hn-launch" : `/${locale}/blog/show-hn-launch`;
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
@@ -22,14 +22,13 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
       description: t("metaDescription"),
       type: "article",
       publishedTime: "2026-02-21T00:00:00Z",
-      url,
     },
     twitter: {
       card: "summary_large_image",
       title: t("metaTitle"),
       description: t("metaDescription"),
     },
-    alternates: { canonical: url },
+    alternates: buildAlternates(locale, "/blog/show-hn-launch"),
   };
 }
 

web/app/[locale]/blog/zen-of-cmux/page.tsx

@@ -1,11 +1,11 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { Link } from "../../../../i18n/navigation";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
   const { locale } = await params;
   const t = await getTranslations({ locale, namespace: "blog.zenOfCmux" });
-  const url = locale === "en" ? "/blog/zen-of-cmux" : `/${locale}/blog/zen-of-cmux`;
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
@@ -18,14 +18,13 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
       description: t("metaDescription"),
       type: "article",
       publishedTime: "2026-02-27T00:00:00Z",
-      url,
     },
     twitter: {
       card: "summary_large_image",
       title: t("metaTitle"),
       description: t("metaDescription"),
     },
-    alternates: { canonical: url },
+    alternates: buildAlternates(locale, "/blog/zen-of-cmux"),
   };
 }
 

web/app/[locale]/community/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { SiteHeader } from "../components/site-header";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
@@ -8,7 +9,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
-    alternates: { canonical: "./" },
+    alternates: buildAlternates(locale, "/community"),
   };
 }
 

web/app/[locale]/docs/api/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 import { Callout } from "../../components/callout";
 
@@ -9,6 +10,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/api"),
   };
 }
 

web/app/[locale]/docs/browser-automation/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
@@ -8,6 +9,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/browser-automation"),
   };
 }
 

web/app/[locale]/docs/changelog/page.tsx

@@ -3,6 +3,7 @@ import path from "path";
 import Image from "next/image";
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { changelogMedia, type VersionMedia } from "./changelog-media";
 
 /** Read PNG dimensions from the IHDR chunk (bytes 16-23). */
@@ -21,6 +22,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/changelog"),
   };
 }
 

web/app/[locale]/docs/concepts/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
@@ -8,6 +9,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/concepts"),
   };
 }
 

web/app/[locale]/docs/configuration/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 import { Callout } from "../../components/callout";
 
@@ -9,6 +10,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/configuration"),
   };
 }
 

web/app/[locale]/docs/custom-commands/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 import { Callout } from "../../components/callout";
 
@@ -9,6 +10,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/custom-commands"),
   };
 }
 

web/app/[locale]/docs/getting-started/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 import { Callout } from "../../components/callout";
 import { DownloadButton } from "../../components/download-button";
@@ -10,6 +11,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/getting-started"),
   };
 }
 

web/app/[locale]/docs/keyboard-shortcuts/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { KeyboardShortcuts } from "../../keyboard-shortcuts";
 
 export async function generateMetadata({ params }: { params: Promise<{ locale: string }> }) {
@@ -8,6 +9,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/keyboard-shortcuts"),
   };
 }
 

web/app/[locale]/docs/layout.tsx

@@ -1,4 +1,5 @@
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { DocsNav } from "./docs-nav";
 import { SiteHeader } from "../components/site-header";
 
@@ -18,9 +19,7 @@ export async function generateMetadata({
       siteName: "cmux",
       type: "article" as const,
     },
-    alternates: {
-      canonical: "./",
-    },
+    alternates: buildAlternates(locale, "/docs"),
   };
 }
 

web/app/[locale]/docs/notifications/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../../i18n/seo";
 import { CodeBlock } from "../../components/code-block";
 import { Callout } from "../../components/callout";
 
@@ -9,6 +10,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
+    alternates: buildAlternates(locale, "/docs/notifications"),
   };
 }
 

web/app/[locale]/layout.tsx

@@ -8,6 +8,7 @@ import {
 } from "next-intl/server";
 import { notFound } from "next/navigation";
 import { routing } from "../../i18n/routing";
+import { buildAlternates } from "../../i18n/seo";
 import { Providers } from "./providers";
 import { DevPanel } from "./components/spacing-control";
 import { SiteFooter } from "./components/site-footer";
@@ -30,8 +31,7 @@ export async function generateMetadata({
 }): Promise<Metadata> {
   const { locale } = await params;
   const t = await getTranslations({ locale, namespace: "meta" });
-  const url =
-    locale === "en" ? "https://cmux.com" : `https://cmux.com/${locale}`;
+  const alternates = buildAlternates(locale, "");
   return {
     title: t("title"),
     description: t("description"),
@@ -52,7 +52,7 @@ export async function generateMetadata({
     openGraph: {
       title: t("title"),
       description: t("ogDescription"),
-      url,
+      url: alternates.canonical,
       siteName: "cmux",
       type: "website",
     },
@@ -61,6 +61,7 @@ export async function generateMetadata({
       title: t("title"),
       description: t("ogDescription"),
     },
+    alternates,
     metadataBase: new URL("https://cmux.com"),
   };
 }

web/app/[locale]/nightly/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { SiteHeader } from "../components/site-header";
 
 export async function generateMetadata({
@@ -12,7 +13,7 @@ export async function generateMetadata({
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
-    alternates: { canonical: "./" },
+    alternates: buildAlternates(locale, "/nightly"),
   };
 }
 

web/app/[locale]/wall-of-love/page.tsx

@@ -1,5 +1,6 @@
 import { useTranslations, useLocale } from "next-intl";
 import { getTranslations } from "next-intl/server";
+import { buildAlternates } from "../../../i18n/seo";
 import { SiteHeader } from "../components/site-header";
 import { testimonials, TestimonialCard, getTestimonialTranslation } from "../testimonials";
 
@@ -9,7 +10,7 @@ export async function generateMetadata({ params }: { params: Promise<{ locale: s
   return {
     title: t("metaTitle"),
     description: t("metaDescription"),
-    alternates: { canonical: "./" },
+    alternates: buildAlternates(locale, "/wall-of-love"),
   };
 }
 

web/app/robots.ts

@@ -2,7 +2,7 @@ import type { MetadataRoute } from "next";
 
 export default function robots(): MetadataRoute.Robots {
   return {
-    rules: { userAgent: "*", allow: "/" },
+    rules: { userAgent: "*", allow: "/", disallow: "/_next/" },
     sitemap: "https://cmux.com/sitemap.xml",
   };
 }

web/app/sitemap.ts

@@ -14,6 +14,7 @@ export default function sitemap(): MetadataRoute.Sitemap {
     { path: "/docs/getting-started", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.9 },
     { path: "/docs/concepts", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.8 },
     { path: "/docs/configuration", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.8 },
+    { path: "/docs/custom-commands", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.7 },
     { path: "/docs/keyboard-shortcuts", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.7 },
     { path: "/docs/api", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.8 },
     { path: "/docs/notifications", lastModified: "2026-03-18", changeFrequency: "monthly" as const, priority: 0.8 },
@@ -27,9 +28,22 @@ export default function sitemap(): MetadataRoute.Sitemap {
     { path: "/eula", lastModified: "2026-03-18", changeFrequency: "yearly" as const, priority: 0.3 },
   ];
 
+  // Legal pages are English-only (not translated), so they only get one entry.
+  const englishOnly = new Set(["/privacy-policy", "/terms-of-service", "/eula"]);
+
   const entries: MetadataRoute.Sitemap = [];
 
   for (const { path, lastModified, changeFrequency, priority } of paths) {
+    if (englishOnly.has(path)) {
+      entries.push({
+        url: `${base}${path}`,
+        lastModified,
+        changeFrequency,
+        priority,
+      });
+      continue;
+    }
+
     const alternates: Record<string, string> = {};
     for (const locale of locales) {
       alternates[locale] =
@@ -37,13 +51,18 @@ export default function sitemap(): MetadataRoute.Sitemap {
     }
     alternates["x-default"] = `${base}${path}`;
 
-    entries.push({
-      url: `${base}${path}`,
-      lastModified,
-      changeFrequency,
-      priority,
-      alternates: { languages: alternates },
-    });
+    // Emit a separate entry for each locale so Google sees every URL declared
+    for (const locale of locales) {
+      const url =
+        locale === "en" ? `${base}${path}` : `${base}/${locale}${path}`;
+      entries.push({
+        url,
+        lastModified,
+        changeFrequency,
+        priority,
+        alternates: { languages: alternates },
+      });
+    }
   }
 
   return entries;

web/i18n/seo.ts

@@ -0,0 +1,22 @@
+import { locales } from "./routing";
+
+const BASE = "https://cmux.com";
+
+/**
+ * Build the full alternates object (canonical + hreflang languages)
+ * for a given locale and path. Use in every generateMetadata that
+ * sets alternates so child metadata doesn't wipe parent hreflang.
+ */
+export function buildAlternates(locale: string, path: string) {
+  const languages: Record<string, string> = {};
+  for (const loc of locales) {
+    languages[loc] =
+      loc === "en" ? `${BASE}${path}` : `${BASE}/${loc}${path}`;
+  }
+  languages["x-default"] = `${BASE}${path}`;
+
+  const canonical =
+    locale === "en" ? `${BASE}${path}` : `${BASE}/${locale}${path}`;
+
+  return { canonical, languages };
+}

web/next.config.ts

@@ -5,7 +5,6 @@ import createNextIntlPlugin from "next-intl/plugin";
 const withNextIntl = createNextIntlPlugin("./i18n/request.ts");
 
 const nextConfig: NextConfig = {
-  skipTrailingSlashRedirect: true,
   images: {
     remotePatterns: [
       {

web/proxy.ts

@@ -15,6 +15,25 @@ export default function middleware(request: NextRequest) {
     return NextResponse.redirect(url.toString(), 301);
   }
 
+  // Legal pages are English-only. Redirect /<locale>/legal-page to /legal-page,
+  // and skip next-intl for /legal-page so locale detection can't redirect back.
+  const legalPages = new Set(["/privacy-policy", "/terms-of-service", "/eula"]);
+  const { pathname } = request.nextUrl;
+  if (legalPages.has(pathname)) {
+    const url = request.nextUrl.clone();
+    url.pathname = `/en${pathname}`;
+    return NextResponse.rewrite(url);
+  }
+  const secondSlash = pathname.indexOf("/", 1);
+  if (secondSlash !== -1) {
+    const rest = pathname.slice(secondSlash);
+    if (legalPages.has(rest)) {
+      const url = request.nextUrl.clone();
+      url.pathname = rest;
+      return NextResponse.redirect(url, 301);
+    }
+  }
+
   return intlMiddleware(request);
 }