B2Build line
Sitemap index generator
One file that points to all your sitemaps. List their URLs, or let the numbering helper write sitemap-1.xml to sitemap-40.xml for you, and download a valid sitemap index.
Sitemap files
url[,lastmod]Nothing leaves your browser.
Options
Numbering helper
Sitemap index
sitemaps.org 0.9When you need an index
A single sitemap may hold 50,000 URLs and 50 MB uncompressed. Larger sites split their URLs over several sitemaps, often by type (pages, posts, products) or by number, and publish an index that lists them; you then submit only the index. The index has the same limits: up to 50,000 sitemaps per file.
Each line becomes a <sitemap> entry with its <loc>, cleaned and XML-escaped like in the sitemap generator. Choose From the list to copy dates from a second column, Today when every file was just regenerated, or None. List sitemaps on the index's own site; an index cannot point to another index.
FAQ
Can the index list .xml.gz files?
Yes. Gzipped sitemaps are fine as long as each one stays under 50 MB once unpacked. Use the exact URLs the files are served from.
What should lastmod mean in an index?
The time that sitemap file last changed, not the newest page in it. Leave it out if you cannot keep it accurate.
Where do I reference the index?
Add a Sitemap: line with its full URL to robots.txt and submit it in Google Search Console and Bing Webmaster Tools.