"Mobile-first indexing" sounds like something on the horizon. It isn't. Google finished the migration on July 5, 2024, after roughly seven years, and Googlebot Smartphone is now the only crawler for every site, with no desktop-only exceptions left (Google Search Central; Search Engine Land, 2024). So the question isn't "should I prepare for mobile-first indexing?" It's "is my site actually fine under it?" Here's what that means in practice for a B2B SaaS, and the short checklist to confirm you're clear.

Key Takeaways - Mobile-first indexing is complete. Google crawls, renders, and indexes the mobile version of your page; if something only exists on desktop, Google doesn't see it (Google Search Central, 2024). - The rule that trips people up: the mobile and desktop versions need the same content, structured data, and metadata (Google Search Central). - Content hidden behind tabs or accordions on mobile still counts for indexing. Content that only loads on user interaction, or only on a viewport Googlebot doesn't simulate, does not. - Your Core Web Vitals are the mobile ones, and only 43% of mobile origins pass all three (HTTP Archive, 2024). Desktop scores are largely irrelevant for ranking now.

Mobile-first indexing is done. What that actually means

Google now crawls your site with Googlebot Smartphone, renders the mobile version, and indexes that. The desktop version is no longer the reference. It rolled out gradually from 2016 and was officially completed on July 5, 2024 (Google Search Central; Search Engine Land, 2024). Practically, that means anything present on your desktop layout but absent on mobile, a sidebar of related links, a section of detail copy, a comparison table that gets dropped at narrow widths, effectively does not exist to Google. It's not penalized; it's just not crawled, because Googlebot never sees the desktop version anymore. Given that mobile is the majority of web traffic worldwide, this is Google indexing the version most people actually use.

The rule that trips people up: parity

Google's mobile-first indexing best practices say it directly: make sure the mobile and desktop versions of your site have the same content, the same structured data, and the same metadata, meaning titles, meta descriptions, and robots directives (Google Search Central). Same images too, with the same alt text. The classic failure is a "lite" mobile version built for speed that quietly strips content, drops images, or omits the JSON-LD that the desktop template includes. Google then indexes the stripped version, and you've removed your own rich-result eligibility and trimmed your own content without realizing it. If you're on a responsive design (one HTML, CSS handles the layout), you're mostly fine by default. If you have a separate mobile site or separate mobile templates, audit them for parity, that's where this breaks.

Hidden content on mobile still counts

Good news first: content tucked behind tabs, accordions, or "read more" toggles on the mobile layout is still indexed. Google treats UX-collapsed content on mobile the same as visible content for indexing purposes, so you don't need to dump every paragraph onto the visible mobile viewport to be safe (Google Search Central). That's a deliberate design choice, because hiding secondary detail behind a toggle is good mobile UX.

The thing that does not count: content that only loads when a user interacts (clicks, scrolls far enough, fills a form), content that requires a viewport size or input Googlebot doesn't simulate, or lazy-loaded content where the trigger never fires during the crawl. The fix is straightforward, make sure anything you want indexed loads when the page loads, on a mobile viewport, without requiring an action. Test it: use Search Console's URL Inspection, "View crawled page," which crawls as Googlebot Smartphone, and check that the content you care about is actually in the rendered HTML.

Core Web Vitals are measured on mobile now

Since the crawler is Googlebot Smartphone, the Core Web Vitals that feed into ranking are your mobile ones. And the mobile bar is the harder one: only 43% of mobile origins pass all three Core Web Vitals (versus 54% on desktop), with LCP the most-failed metric at roughly 52% on mobile (HTTP Archive, 2024). So when you pull a Lighthouse report, the desktop tab is mostly a vanity exercise as far as ranking goes, look at the mobile field data in the Chrome UX Report. For the SaaS-specific version of the Core Web Vitals picture, see Core Web Vitals for B2B SaaS in 2026.

The Mobile Usability report is gone, and that's fine

If you went looking for the Mobile Usability report in Search Console and couldn't find it, that's expected, Google removed it in late 2023, along with the standalone Mobile-Friendly Test tool and the Mobile Usability API (Google Search Central). Google's reasoning was that mobile-friendliness has become table stakes, the report's data was redundant with what modern frameworks handle by default, and it wasn't adding value. So there's no dedicated mobile report to monitor anymore. What you use instead: URL Inspection (which shows "Crawled as: Smartphone"), the Core Web Vitals report, and the Page Indexing report. The absence of the report is itself the message, Google considers basic mobile usability so fundamental it's not worth a separate dashboard.

The SaaS checklist

Six quick checks to confirm you're clear under mobile-first indexing:

• View your important pages in a mobile viewport, or use URL Inspection's "View crawled page." Is anything present on desktop but missing on mobile? If so, fix it, Google isn't seeing it.

• Confirm parity of titles, meta descriptions, robots directives, and structured data between the mobile and desktop versions. A responsive site is fine by default; a separate mobile site needs auditing.

• Make sure lazy-loaded content loads during the crawl, not only on scroll or interaction.

• Check that images on the mobile version have alt text, the same alt text as desktop.

• Don't serve a stripped-down mobile site or rely on AMP-only content. The mobile version is now the canonical version; make it the full version.

• Treat your Core Web Vitals as the mobile ones. Use CrUX field data, fix LCP first, and don't get distracted by good desktop Lighthouse scores.

Frequently Asked Questions

Is mobile-first indexing still happening, or is it done?

It's done. Google completed the migration on July 5, 2024, after roughly seven years, and Googlebot Smartphone is now the sole crawler with no desktop-only exceptions (Google Search Central; Search Engine Land, 2024). There's nothing to "switch on" or prepare for; the only question is whether your site holds up under it.

Does Google index content hidden behind tabs on mobile?

Yes. Content collapsed behind tabs, accordions, or "read more" toggles for mobile UX is treated the same as visible content for indexing (Google Search Central). What's not indexed is content that only loads on user interaction, or lazy-loaded content whose trigger never fires during the crawl, so make sure anything you want indexed is in the rendered HTML when the page loads on a mobile viewport.

Do I need a separate mobile site for mobile-first indexing?

No, and a separate mobile site usually makes things harder, not easier. A responsive design (one HTML, CSS handles layout) satisfies mobile-first indexing by default. If you do have a separate mobile site or separate mobile templates, you need to audit them for content, structured-data, and metadata parity with the desktop version, because Google indexes the mobile one and any gaps become real losses.

What happened to the Mobile Usability report in Search Console?

Google removed it in late 2023, along with the Mobile-Friendly Test tool and the Mobile Usability API, on the basis that mobile-friendliness is now baseline and the report wasn't adding value (Google Search Central). Use URL Inspection ("Crawled as: Smartphone"), the Core Web Vitals report, and the Page Indexing report instead.

Does mobile-first indexing affect my desktop rankings?

There's effectively one index now, built from the mobile crawl, so your "desktop rankings" are determined by the mobile version of your page. Optimizing the desktop layout in isolation does little; what matters is that the mobile version has the full content, the structured data, and decent mobile Core Web Vitals (only 43% of mobile origins pass all three, HTTP Archive, 2024).

The bottom line

Mobile-first indexing stopped being a project and became the default a year ago. For most B2B SaaS sites on a responsive design, you're fine, but it's worth one pass to confirm: does the mobile version have everything the desktop version does (content, schema, metadata), does your lazy-loaded content actually load for the crawler, and are you treating Core Web Vitals as the mobile numbers? If yes on all three, there's nothing more to do. If no on any of them, that's a fix worth making, because the mobile version is the only version Google sees now.