Sitemap Index vs Single Flat File: Pick The Threshold, Not The Vibe

Sitemap Index vs Single Flat File: Pick The Threshold, Not The Vibe

Decision rule by URL count:

— Under 50,000 URLs: ship one flat sitemap.xml. An index here just adds a hop for no benefit.
— 50,000 to ~500,000 URLs: sitemap index referencing child files, each ✅ under 50,000 URLs and ✅ under 50MB uncompressed.
— Over 500,000 URLs: index + segment children by section (/blog, /products) so you can read GSC coverage per segment.

Why segment instead of arbitrary 50k chunks: GSC reports submitted/indexed counts per child file. Section-based children turn that into a diagnostic; random chunks turn it into noise.

Definition of done:
— One index at /sitemap.xml, max 50,000 child files.
— Each child passes both limits (50k URLs, 50MB).
— Children grouped by content type, not by ingestion order.