What is the best free SEO tool?

Google Search Console is generally considered the best free SEO tool available, since it comes directly from Google itself and shows exactly how your pages actually perform in real search results, impressions, clicks, and average position all included.

Google's own PageSpeed Insights and Rich Results Test round out a genuinely strong free toolkit, covering site speed and structured data checks respectively without costing anything at all to run.

Free tools cover diagnostics reasonably well overall, but they rarely handle the writing and publishing side of SEO, which is exactly where the real time cost tends to pile up for anyone doing this manually.

Handling that writing and publishing gap is where automatic SEO software picks up.