Infer Schema from XML Sitemap Files

XML Sitemap to JSON Schema

XML sitemaps are used by search engines to discover and index website pages. They follow a well-defined structure but with some variation in optional fields.

Example Sitemap

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/</loc>
    <lastmod>2024-01-15</lastmod>
    <changefreq>daily</changefreq>
    <priority>1.0</priority>
  </url>
  <url>
    <loc>https://example.com/about</loc>
    <lastmod>2024-01-10</lastmod>
    <changefreq>monthly</changefreq>
    <priority>0.8</priority>
  </url>
  <url>
    <loc>https://example.com/blog</loc>
    <changefreq>weekly</changefreq>
    <priority>0.9</priority>
  </url>
</urlset>

Generated Schema

{
  "type": "object",
  "properties": {
    "urlset": {
      "type": "object",
      "properties": {
        "url": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "loc": { "type": "string" },
              "lastmod": { "type": "string" },
              "changefreq": { "type": "string" },
              "priority": { "type": "number" }
            }
          }
        }
      }
    }
  }
}

Schema Insights

• URL array: Multiple <url> elements correctly become an array
• Priority as number: Values like 1.0, 0.8, 0.9 are detected as numbers
• Optional fields: If lastmod is missing from some entries (like the third URL above), required field detection will not include it
• Dates as strings: lastmod values remain strings since JSON Schema has no native date type

Sitemap Index

The same approach works for sitemap index files:

<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>https://example.com/sitemap-posts.xml</loc>
    <lastmod>2024-01-15</lastmod>
  </sitemap>
</sitemapindex>

Enhancing the Schema

For production use, you would add:

• format: "uri" to loc
• enum: ["always", "hourly", "daily", "weekly", "monthly", "yearly", "never"] to changefreq
• minimum: 0.0, maximum: 1.0 to priority
• format: "date" to lastmod