Google Search Console

Google Search Console shows which search queries actually bring traffic to your site, along with impressions, click-through rate and average position for each one.

That query data is not available anywhere else: analytics tools show what visitors did after arriving, but only Search Console shows what they searched to get there — which is the input SEO work actually depends on.

It also reports indexing problems, mobile usability issues and manual penalties. Verifying a site here should be the first step after launch, before any optimization work begins.