Mobile SEO: mobile-first indexing and responsive design
Mobile SEO is optimising for the fact that most searches, and the search engine’s own indexing, now happen on mobile first. The phone version of your site is no longer a secondary experience — it is the one being ranked.
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What mobile-first indexing means
Mobile-first indexing means search engines predominantly use the mobile version of a page to understand and rank it. If content, links, or structured data exist on desktop but are stripped out on mobile, the engine may never see them.
The practical implication is that the mobile experience must be complete, not cut down. Anything important to ranking — the full content, the internal links, the markup — has to be present in the mobile view, not hidden or removed to save space.
Responsive design as the default
Responsive design serves the same HTML to every device and adapts the layout with CSS. It is the recommended approach because there is a single version to maintain, one URL per page, and no risk of content diverging between mobile and desktop.
The alternatives — separate mobile sites or dynamically served versions — introduce duplication and sync problems that responsive design avoids entirely. For most sites, responsive is both the simplest and the safest choice.
Mobile usability details
Beyond having the content, the mobile experience has to be usable. Tap targets need room so people do not mis-hit, text must be legible without pinching, and intrusive pop-ups that cover the content can be penalised as well as being resented.
Speed matters most on mobile, where connections and devices are often weaker. The same performance work that helps Core Web Vitals — lean images, less blocking script — pays back double on a phone, where patience is thinner.
Where Kirti fits
Kirti is being built to check the mobile view as part of its technical audit — confirming the content and markup match the desktop version and flagging usability and speed issues on phones — and to propose fixes for the team to approve.
The agent is in active development and not yet generally available, so this guide focuses on the principles, which apply to any responsive site regardless of tooling.