Free SEO tools for developers
Six tools for the problems that keep sites off Google. No account, no email. Each result comes with a prompt you can paste into Claude Code, Codex or Cursor to fix it.
- SEO checkerCheck one page the way a crawler sees it: server HTML, title, canonical, noindex, sitemap, structured data and Open Graph.Checks the live URL
- Robots.txt testerPaste a URL and see whether Googlebot and AI crawlers may fetch it, which rule decides, and what your robots.txt gets wrong.Checks the live URL
- Sitemap validatorValidate an XML sitemap or sitemap index: format, size limits, lastmod dates, and whether the listed URLs actually load.Checks the live URL
- Redirect checkerFollow every hop from a URL to its final page: status codes, chains, loops, and the HTTP, www and trailing-slash variants.Checks the live URL
- Google result previewSee how your title and description look in Google on desktop and mobile, with pixel widths and where they get cut off.Runs in your browser
- Schema generatorBuild valid JSON-LD for organizations, articles, products, breadcrumbs and more, with the properties Google requires.Runs in your browser
Which tool do I need?
| What you see | Start with |
|---|---|
| A page isn't showing up on Google | SEO checker |
| Search Console says “Blocked by robots.txt” | Robots.txt tester |
| You want to know if AI crawlers can read your site | Robots.txt tester |
| Search Console says “Couldn't fetch” for your sitemap | Sitemap validator |
| You moved pages or switched domains | Redirect checker |
| “Page with redirect” in the indexing report | Redirect checker |
| Your title gets cut off in search results | Google result preview |
| You want rich results or a clearer site name | Schema generator |
How these tools work
- Nothing is stored. Tools that check a live URL fetch it once, the way a crawler would, and forget it. The result preview and schema generator never send what you type anywhere.
- Crawler manners. Live checks read robots.txt first and fetch only a handful of URLs per check, from Serpkin's own crawler.
- Made for agents. Every result ends with a prompt that lists each issue with what was observed, so your coding agent can find the files and fix them.
- One page at a time. For the whole site, ranked fixes and results measured after you ship, Serpkin runs these checks and more on every page.