Bing Caching - 125 KB Limit

Question

In Bing's Webmaster Tools, they have a warning if your html is over 125KB.

It states:

Evaluated size of HTML is estimated to be over 125 KB and risks not being fully cached.

Recommended action

Ensure that the page source does not contain large amounts of CSS or code at the top of the page. Consider moving code and styles into separate files.

Search engines may not fully acquire the content on a page if the page is contains a lot of code. Extraneous code can push the content down in the page source making it harder for a search engine crawler to get to. A soft limit of 125 KB is used for guidance to ensure all content & links are available in the page source to be cached by the crawler. This basically means if the page size is too big, a search engine may not be able to get all of the content or may end up not fully caching it.

• Does anyone know what type of caching this is referring to?
• Is it just referring to the cached copy of the page which users can view?

I tried asking the Bing Webmaster Tools support contact for details, but they seem to not know much about it.

I asked them:

• Could you clarify what it's referring to regarding "not fully caching"?
• Does this mean that content after 125KB will not be indexed?
• Does "soft limit" mean that that's not the actual limit?
• If so, how much higher is the actual limit?

In their first response to my questions, they responded with a vague:

I would like to inform you that the recommendation is correct. Please reduce the size of the overall HTML page.

When I repeated the same questions to them, they responded with:

Firstly Caching is a way of making a web page appear faster. That is the short way to explain it, but of course there is a whole process behind data caching techniques.

Secondly No it doesn't mean content after 125KB will not be indexed.

125 KB is the actual higher limit. For more info on this please reach out to your SEO specialist for better understanding.

This second vague response seems to imply that it doesn't affect indexing, and might be referring to the cached webpage feature. Does this sound correct?

Answer 1

I was stumbling above the same SEO warning of Bing's webmaster tools.

The description you linked (which is still there at time of writing) indicates that it's about the search crawler internal cache, not about any relevant cache for regular visitors: I never heard of a browser, CDN or web stack with such a small cache limit for an HTML document.

Since the Bing webmaster support indicates that it does not affect Bing indexing, I guess it refers to potential limits of other search engine crawlers, as a generally failsafe recommendation. Since at least Google and Yandex search console/webmaster tools do not have such a warning, I would rate this as outdated, nowadays false SEO recommendation, from a pre-HTML5 time where websites were build up as a single scrollable HTML and/or with multiple sections or blog posts and H1 tags much less often.

Bing webmaster until time of writing has more such obsolete SEO warnings, like the mentioned multiple H1 tags which are allowed and common with HTML5, e.g. used by Wordpress blog overview/list pages and mentioned scrollable single HTML sites (with mobile phones in mind), or that it does not detect the title and description meta tags at the top of the HTML when head and body tags are not explicitly present (which are optional in HTML5, added by clients automatically internally). So I would rate the 125 KiB warning as one of those which should be removed or adjusted by Bing to stop confusing and misguiding web masters.