Free SEO checkers

By Matt Kerr·Published 6 October 2026

Free checks you can run on any page, in your browser. No sign-up required and nothing to install. Each one answers one question in a few seconds.

• SEO checker: What is wrong with this page, how bad is it, and what should be fixed first?
• AI crawler checker: Can ChatGPT, Claude, Perplexity and Google's AI Overviews read your site?
• Robots.txt tester: Is this exact page open or blocked for Googlebot, Bingbot and the AI crawlers, and which line decides?
• Title and meta tag checker: Is this page's title the right length, is it indexable, and what will a shared link show?
• JSON-LD structured data checker: Is this page's structured data valid, and is anything missing that a rich result needs?
• ADA Title II date checker: Which ADA Title II website date applies to us, and which documents are exempt?
• Redirect chain checker: Where does this address send people, through how many hops, and with which status codes?
• HTTP header checker: Which headers does this page send, and are the ones search engines and browsers rely on right?
• Search result preview: How will a title and description look in a search result, and where will they be cut off?

Which one to use

You want to know what is wrong with a page, and what to fix first. Start with the SEO checker. It reads the page and its robots.txt, gives a score, counts the problems in each area and puts the worst one at the top with the fix. The checkers below go deeper on one question each.

A page dropped out of search, or never showed up. Start with the robots.txt tester. Paste the page's own address, not the homepage, because rules are written per path and the homepage can be open while a whole section is closed. It names the line that decides, which is the line to change.

ChatGPT, Claude or Perplexity never mention you. The AI crawler checker reads the same file for the crawlers those assistants send, and splits the ones that let an assistant quote you from the ones that only collect training data. Blocking the second kind is a reasonable choice; blocking the first kind usually is not.

A search result shows the wrong title, or a cut-off one. The title and meta tag checker measures the title and description the way Check Engine does, by width rather than character count, and checks the tags that decide whether the page can be indexed and what a shared link shows.

An old link lands somewhere odd, or the browser says too many redirects. The redirect checker follows the address one hop at a time and shows each status code, so the hop that loops or should not be there is easy to spot. The HTTP header checker reads what the final response says about indexing, caching and security.

You are writing a new title and want to see it first. The search result preview shows the title and description as a result would, before anything is published, and marks where Check Engine expects each to be cut off. It needs no address: type the words and watch.

You want the basics checked on every page you open. The free Check Engine SEO add-on for Chrome checks the page in the tab you are on, in your browser, with nothing uploaded and no account.

Stars, prices or FAQs never appear under your result. The JSON-LD checker reads every structured data block on the page, says which line breaks the JSON, and lists the properties a rich result needs that are missing.

What a free check can and cannot tell you

Each checker reads what a crawler would read at the moment you ask: one robots.txt file, for one page. It cannot see a firewall or CDN that refuses a crawler the file allows, and it does not look at the rest of your site. The rules come from Check Engine, the desktop app these pages belong to, so a free check and the app give the same answer for the same page. The checkers fetch only what they need, name themselves in the request, keep a copy for a few minutes so repeated checks do not hit your server, and store nothing about the sites checked.

Check Engine runs 99 checks across a site and checks robots.txt rules for 22 AI crawlers. A separate check requests your homepage as 9 AI crawlers plus Googlebot to find server refusals the file cannot show. It ranks what to fix first.

Choosing between audit tools?

These pages set Check Engine beside the tools people most often weigh it against. Each vendor's prices and limits are read from its own pages and dated, each page ends with when to pick the other tool instead, and each shows a real Check Engine audit.

• SE Ranking vs Screaming Frog: a cloud audit metered by pages per month against a desktop crawler with no meter.
• Check Engine vs Ahrefs Site Audit: one module of a keyword and backlink platform against a one-time Mac audit.
• SEOptimer alternative: white-label reports and a monthly crawl allowance against an unmetered audit you run yourself.