/sitemap

name: xml-sitemap
description: When the user wants to create, audit, or optimize sitemap.xml. Also use when the user mentions "sitemap," "sitemap.xml," "sitemap index," "lastmod," "changefreq," "priority," "URL discovery," "URL discovery for search engines," "single source of truth," "URL config," "unify sitemap IndexNow," or "reduce duplicate maintenance." For IndexNow, use indexnow.
metadata:
  version: 1.1.0

SEO Technical: Sitemap

Guides sitemap creation, auditing, and optimization for search engine discovery.

**When invoking**: On **first use**, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On **subsequent use** or when the user asks to skip, go directly to the main output.

Scope (Technical SEO)

• **Sitemap**: Create XML sitemap; submit to Google Search Console
• **URL discovery**: Help search engines find pages; especially important for large sites or poor internal linking

Task

Generate an XML Sitemap that complies with the sitemaps.org protocol from the project's page list, and declare it in robots.txt.

Initial Assessment

**Project context:** Read root `{project}.md` when present and load only the modules relevant to this task. Without Contextus, use available project material or user-provided facts and ask for missing information; do not create a parallel context system.

Identify: 1. **Site URL**: Base domain (e.g., `https://example.com`) 2. **URL count**: Total indexable pages (single sitemap vs. sitemap index) 3. **Data source**: Static config, CMS, file system, or hybrid

Precondition: Does the site need a sitemap?

Before generating, assess whether a sitemap is warranted. A sitemap is most valuable when:

• **Large site** (hundreds+ pages) or **new site** with few backlinks
• **Deep or orphaned pages** that internal links don't reach well
• **Rich media** (images, videos, news) needing extension metadata
• GSC shows growing "Discovered – not indexed" or "Not discovered" counts

Small sites (< 50 pages) with strong internal linking may not strictly need one, but creating a sitemap has near-zero cost and provides future-proof infrastructure. If in doubt, err on the side of creating.

1. Protocol Essentials

| Item | Spec | |------|------| | Single sitemap limit | 50,000 URLs, 50MB (uncompressed) | | Sitemap index | When exceeding limit, split and have main index reference sub-sitemaps | | Encoding | UTF-8 | | URL format | Full URL, same host, include `https://` | | Required tags | `<loc>` | | Optional tags | `<lastmod>`, `<changefreq>`, `<priority>` |

2. Field Requirements

| Field | Description | Recommendation | |-------|--------------|---------------| | url | Full URL | `https://example.com/path` | | lastModified | Page last modified time | Use page metadata, ISO 8601; use `YYYY-MM-DD` or omit when no data | | changeFrequency | Update frequency | Home `daily`, list pages `weekly`, content pages `monthly` | | priority | Relative importance | Home 1.0, aggregate pages 0.9, content pages 0.7–0.8, others 0.5–0.6 |

lastmod (Critical)

• **Must be accurate**: Reflect actual page modification time, not sitemap generation time. Google requires verifiability; Bing reports ~18% of sitemaps have incorrect lastmod values.
• **Format**: W3C Datetime (`YYYY-MM-DD` or `YYYY-MM-DDTHH:MM:SS+TZD`), e.g. `2025-01-15`, `2025-01-15T14:30:00+08:00`.
• **Avoid**: Using `new Date()` for lastmod—causes all URLs to share the same timestamp; search engines may ignore.
• **Apply when**: Content updates, structured data changes, or important link changes.

changefreq / priority

• **changefreq**: Hints only; does not directly determine crawl frequency. Values: `always`, `hourly`, `daily`, `weekly`, `monthly`, `yearly`, `never`.
• **priority**: 0.0–1.0; **does not affect ranking**; set higher for important pages; avoid identical values for all.

3. Architecture & Split

Single Sitemap

• When URLs >50,000, generate `/sitemap.xml` directly.

Sitemap Index (Multiple Sub-sitemaps)

• When exceeding limit, split by type or language; main index references sub-sitemaps.
• Example splits: `/sitemap/posts.xml`, `/sitemap/pages.xml`, `/sitemap/zh.xml`, `/sitemap/en.xml`.
• Main index outputs `/sitemap.xml` or `/sitemap-index.xml`, each entry as `<sitemap><loc>...</loc></sitemap>`.

Multilingual Sites

• Split by locale: `/sitemap/zh.xml`, `/sitemap/en.xml`.
• Or by content type + language: `/sitemap/zh-posts.xml`, `/sitemap/en-posts.xml`.

Multi-Language Sitemap (hreflang in Sitemap)

For multilingual sites, add `xhtml:link` hreflang alternates inside each `<url>` entry. **Recommended for large sites** (100+ multilingual pages); centralizes hreflang management.

**Rules**:

• Every language version must link to ALL others, including itself (self-reference).
• Include `x-default` pointing to default locale.
• Use `xmlns:xhtml="http://www.w3.org/1999/xhtml"` namespace.
• `<loc>` typically uses default-locale (clean) URL; `x-default` points there too.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <url>
    <loc>https://example.com/page</loc>
    <xhtml:link rel="alternate" hreflang="en" href="https://example.com/page" />
    <xhtml:link rel="alternate" hreflang="zh" href="https://example.com/zh/page" />
    <xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/page" />
  </url>
</urlset>

List all language sitemaps in sitemap index; include in robots.txt.

4. Implementation

| Tech Stack | Implementation | |------------|-----------------| | Next.js App Router | `app/sitemap.ts` export `MetadataRoute.Sitemap` or `generateSitemaps` | | Next.js Pages Router | `pages/sitemap.xml.ts` or `getServerSideProps` return XML | | Astro | `src/pages/sitemap-index.xml.ts` or `@astrojs/sitemap` | | Vite / Static build | Build script generates `public/sitemap.xml`