Google's John Mueller calls the daily-crawl sitemap trick a bad idea

The technique

Some SEOs have started appending a changing parameter, such as ?v= followed by a Unix timestamp, to the child sitemap URLs inside a sitemap index. The goal is to force search engines to refetch the sitemap file every day, instead of leaving that decision to the <lastmod> field, which normally tells a crawler whether a page has actually changed.

A Bluesky user posting as @seoharbour asked Google's John Mueller about it, describing what they had observed on a large, rigidly structured site, where the child sitemap URLs pick up a fresh timestamp parameter every day.

Mueller calls it a bad idea

Mueller's first reaction was to question the goal: "Why would you use cache-busting in a sitemap file?" After @seoharbour explained the setup, he gave a direct answer: it is "a bad idea." His reasoning was that appending a changing parameter signals that the canonical URL for a piece of content should keep changing. He said that hurts search engines and hurts a site's own tracking, and that stable, clean URLs matter.

What is still unverified

The exchange settles Google's opinion of the practice. It does not settle whether the trick actually increases crawl frequency. Neither Mueller nor Search Engine Journal's reporting states that appending a timestamp changes how often Googlebot visits a page. The outlet frames the whole technique as an SEO influencer hack, something that sounds clever on paper without reflecting how XML sitemaps are meant to work.

Why this matters beyond classic SEO

AI Overviews, Perplexity and ChatGPT's browsing features draw on freshly crawled index data, so crawl frequency is directly tied to how fast new or updated content can surface in AI answers. That is exactly why this technique looked appealing. But the mechanism Google is warning against, a sitemap URL that churns daily, undermines the one thing those systems need to cite a page reliably: a stable identifier for it. Google's advice points the other way. Keep the URL fixed and let <lastmod> carry the freshness signal.