Semrush Review (2026): The Free Audit Found a Real DNS Bug

We ran Semrush’s free Site Audit and AI Visibility tools against solostacklab.net - no signup, no credit card. We deliberately stayed in the free tier: Semrush’s own official pricing page confirms the 7-day trial of paid plans requires a card, and its money-back guarantee explicitly excludes month-to-month billing - the same refund-guarantee trap shape we already documented in the Surfer SEO review.

(Update, Sep 27: as part of a routine pricing/feature recheck, we went back to semrush.com/siteaudit/ to confirm this was still true. What’s there now is a free “SEO Checker” that analyzes 1 page, not the 100-page Site Audit we tested in August - the page’s own comparison table lists “Pages analyzed: 1 page” for the free tool versus “100 pages” for “Semrush Site Audit.” Running the 1-page checker against our own site also returned results that don’t match reality (it called the site “not mobile friendly,” which it is). The link to the full “Site Audit” now points to semrush.com/signup/...&trial=force... - an account-creation page - rather than to a report. Our first two re-test attempts weren’t clean: one hit a shared daily usage cap before showing a result, and one used a browser already logged in to Semrush from earlier testing, which skips the no-signup path entirely rather than proving it still exists.)

(Update, Sep 29: a clean re-test - a different Google account, logged out of Semrush, on the same URL - reached the same 1-page checker, not the 100-page audit. The false “not mobile friendly” flag reproduced too, alongside a Performance Score of 100/100 on the same page - a direct contradiction on its own dashboard.)

So we can confirm the entry point we used in August has changed shape, and a second, cleaner test still couldn’t reach a free 100-page audit - but we still can’t rule out one existing somewhere else on the site we haven’t found. Treat the rest of this review as a record of what we found in August, not a current claim that the same free path is still open today.

It found a real bug nothing else had caught

The audit flagged one page as “couldn’t be crawled (DNS resolution issue)”: https://www.solostacklab.net/. We checked with nslookup and confirmed it directly - the www subdomain had no DNS record at all (NXDOMAIN), not a redirect, not a 404. A genuine gap.

This is a bug Screaming Frog’s crawl couldn’t have caught the week before - Screaming Frog only follows a site’s own internal links, and nothing on solostacklab.net links to the www variant. Semrush’s audit apparently tests both forms directly rather than relying purely on discovered links. We fixed the DNS gap same-session: added www.solostacklab.net as a custom domain in Cloudflare Pages, which auto-created the missing CNAME record and served the site over SSL.

(Correction, Sep 19: an earlier version of this page said www “now redirects to the apex domain.” That was wrong. For four weeks www served a full duplicate copy of the site with HTTP 200 instead of redirecting. Every page’s canonical tag pointed at the apex domain, which limited the damage, but it was not a redirect. We caught it while tracing the redirect share in Google Search Console’s crawl stats, and added a proper 301 rule from www to the apex domain on Sep 19. The general lesson - re-test a claim about your own site’s live behavior instead of trusting what you wrote down earlier - is in our guide to sanity-checking a backlink report, which uses this same mistake as an example.)

What else the free tier showed

• AI Visibility tracking (ChatGPT, AI Overview, AI Mode, Gemini) showed 0% presence - consistent with SE Ranking’s earlier 0% AI-citation finding for the same domain, a useful cross-tool confirmation rather than a one-off number.
• The same /cdn-cgi/l/email-protection 4xx “broken link” that Screaming Frog flagged also showed up here. It’s Cloudflare’s own email-obfuscation feature rewriting the email addresses we quote in the SE Ranking review - not a real bug, now confirmed by two independent tools.
• Core Web Vitals is paywalled (“Available with a paid plan”) even on the free tier - the same paywalled-audit-detail pattern we found in Surfer SEO’s Auto-Optimize button and SE Ranking’s Site Audit detail view.

Two dashboard warnings that oversold themselves

“12 pages have duplicate H1 and title tags” sounds like a duplicate-content problem across the site. It isn’t. Checking each flagged page, every one simply has its own <title> matching its own <h1> - a deliberate choice on this site (title doubles as the on-page heading), not two pages sharing content. The label implies cross-page duplication; the actual issue is same-page consistency, which is normal SEO practice.

“5 pages have a low word count” flagged our five index/listing pages: the homepage, /reviews/, /guides/, /comparisons/, and /disclosure/ - all pages that intentionally list links rather than carry prose. The metric doesn’t distinguish a hub page from an article, so it counts every list page as thin content by default.

A vanity metric worth calling out

The Position Tracking widget shows 100% visibility, position 1 for the keyword solostacklab.net - i.e., this site ranks #1 for a search of its own domain name. That’s true of essentially every domain on the internet and isn’t an achievement, but the dashboard presents it with the same visual weight as a real ranking win. Worth knowing before reading any “position 1!” screenshot from this tool, including ours above, at face value.

Bottom line

In August, Semrush’s free, no-signup Site Audit and AI Visibility tools were real and useful - the DNS bug they caught was a real gap in our own setup that two other tools had missed. As of Sep 27, we could not retrace that same no-signup path to a 100-page audit; what’s openly available without an account now looks like a smaller 1-page tool with results we don’t fully trust (see the update above). If you still find the full free Site Audit without creating an account, several of its warnings need a second look before you act on them regardless: check what a flagged “duplicate” or “low word count” page actually is before treating the label as ground truth, and don’t mistake ranking for your own brand name for a real visibility win. See our best AI & SEO tools roundup for how it stacks up against the other audit tools we’ve tested.

One thing its audit did not report on our site in August: unknown URLs answering with HTTP 200, a soft 404. We wrote up why a crawler can miss that, and a one-minute test for it, in our soft-404 guide. If you’re deciding between it and SE Ranking, our Semrush vs SE Ranking comparison puts Semrush’s free tier next to SE Ranking’s trial.