IMVASA

Free SEO audit tools compared

The Best Free SEO Audit Tools in 2026 (Compared Honestly)

No free SEO audit tool does everything. Each free tier gives away one job and charges for the rest. This page sets out what 10 popular tools really give you for free, with every limit taken from the vendor's own pages, so you can pick the right one for the job in front of you.

Written by Vasa, GEO & AEO specialist · Last updated

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The short answer

Audit one page, no account
IMVASA
Crawl a whole site, up to 500 URLs
Screaming Frog
Audit and backlinks for your own site
Ahrefs WMT
What Google actually indexed
Search Console
Real-user speed
PageSpeed Insights
Branded PDF reports for clients
SEOptimer

What "free" really gets you

The free allowance is where these tools differ most, and where their landing pages are vaguest. Limits below are as each vendor states them, checked in October 2026.

ToolFree allowanceNeedsBest for
IMVASA Audit ToolSingle-page SEO and AI search audit206 checks on any URL, up to 20 audits an hourNoneFixing one important page, today
Semrush (free account)All-in-one suite on a free accountSite Audit up to 100 pages a month in 1 project; 10 analytics reports a dayFree accountTrying Semrush's data before you pay
Ahrefs Webmaster ToolsSite audit and backlinks for sites you ownSite Audit 5,000 crawl credits a month per project; up to 1,000 backlinks and keywords shownAccount and verified ownershipWatching your own site's health over time
Screaming Frog SEO Spider (free)Desktop crawler500 URLs per crawlDesktop install, no accountCrawling a small site end to end
SEOptimerAudit reports for agenciesA one-off audit on their site; plans from $29 a month after a 14-day trialNone for the one-off auditBranded PDF reports for clients
SEOmatorFree tool collection and paid crawler29+ free tools without signup, including a single-page audit; plans from $49 a monthNone for the free toolsQuick single-issue checks
Google Search ConsoleGoogle's own index dataFree for verified ownersGoogle account and verified ownershipWhat Google actually crawled and indexed
PageSpeed InsightsSpeed and Core Web VitalsFree, any URLNoneReal-user speed (Core Web Vitals)
Bing Webmaster ToolsBing's index data and Site ScanFree for verified ownersAccount and verified ownershipVisibility in Bing and Copilot
HubSpot AI Search GraderAI brand perceptionFree, after a short formNoneHow AI models describe your brand

IMVASA is our tool. We list its limits the same way we list everyone else's.

Free alternatives to Semrush

Semrush's free account allows Site Audit on 100 pages a month in one project and 10 analytics reports a day. When you hit those limits, no single free tool replaces it, but most of its jobs have a free stand-in:

Site audit
IMVASA for any single page, Ahrefs Webmaster Tools for a whole site you own, Screaming Frog for up to 500 URLs of any site.
Backlinks
Ahrefs Webmaster Tools, for sites you can verify.
Your own keywords and rankings
Google Search Console: the queries you appear for, with clicks, impressions and average position.
Speed and Core Web Vitals
PageSpeed Insights.
AI search readiness
IMVASA's AI search checks, or the free GEO audit for an AI-only report.
Competitor keywords and traffic
No free replacement. Those databases cost real money to build, so every honest free tier caps them hard.

Tool by tool

What each one is good at, and where its free version stops.

IMVASA Audit Tool

Single-page SEO and AI search audit

Best for: Fixing one important page, today

Good at

  • 206 checks in 16 categories on any public URL, competitors included, each with the evidence from the page's own HTML and the fix.
  • AI search checks in the same report: 13 AI crawlers tested against robots.txt (search and training bots scored separately), content present in the server HTML, answer-first passages and llms.txt format.
  • A heading tree, a schema entity graph, and a copy-paste fix prompt for ChatGPT, Claude, Cursor or Copilot.
  • A share link that does not expire, and a free MCP server so assistants can run audits without a key.

Where it stops

  • One page per run. Deep mode samples up to 8 pages from your sitemap; it is not a whole-site crawler.
  • Reads the HTML your server sends and does not run JavaScript, so it flags client-rendered pages rather than rendering them.
  • No backlink index, keyword volumes or rank tracking.
  • No branded PDFs. You can print a report to PDF, but it carries no agency logo.

Run a free audit

Semrush (free account)

All-in-one suite on a free account

Best for: Trying Semrush's data before you pay

Good at

  • Site Audit crawls the whole site, not one page, and groups what it finds into errors, warnings and notices.
  • Site Audit now scores AI search health too, including whether AI crawlers such as OAI-SearchBot and PerplexityBot are blocked, and llms.txt.
  • A taste of the keyword and domain databases, which no free-only tool has.

Where it stops

  • 100 pages a month runs out on the first crawl of most real sites.
  • 10 analytics reports a day, with results cut short, is enough to look around, not to work in.
  • Everything past that sits behind a 7-day trial and the paid plans.

semrush.com

Ahrefs Webmaster Tools

Site audit and backlinks for sites you own

Best for: Watching your own site's health over time

Good at

  • Whole-site crawls of every site you can verify, with no cap on the number of projects.
  • Site Explorer on your own site: backlinks and organic keywords, up to 1,000 rows at a time.
  • The closest thing to a free Semrush for a site you own.

Where it stops

  • Only works on sites you can verify, so no competitor audits and no client prospecting.
  • You set up an account and prove ownership before the first crawl.
  • The full backlink and keyword views are on paid plans.

ahrefs.com

Screaming Frog SEO Spider (free)

Desktop crawler

Best for: Crawling a small site end to end

Good at

  • Broken links, redirects, titles and meta, meta robots, hreflang and exact duplicates across up to 500 URLs.
  • Builds an XML sitemap and site visualisations from the crawl.
  • Crawls any site, competitors included, from your own machine.

Where it stops

  • JavaScript rendering, saved crawls, custom extraction, structured data validation, scheduling and the Search Console and PageSpeed integrations need the €245 a year licence.
  • A dense, spreadsheet-style interface built for technical SEOs.
  • Nothing scores AI search readiness out of the box.

screamingfrog.co.uk

SEOptimer

Audit reports for agencies

Best for: Branded PDF reports for clients

Good at

  • Letter grades a non-technical client understands at a glance.
  • White-label PDF reports and an embeddable audit form that turns site visitors into leads.

Where it stops

  • Saving, monitoring and branded reports are paid: DIY SEO $29, White Label $39, White Label & Embedding $59 a month.
  • The report is written to sell SEO work to a client more than to hand a developer a fix.

seoptimer.com

SEOmator

Free tool collection and paid crawler

Best for: Quick single-issue checks

Good at

  • No-signup tools for one job each: SEO audit, keyword research, backlink checker, SERP rank checker, speed test and mobile-friendly test.

Where it stops

  • Each free tool is its own page, so the results never add up to one report.
  • Site-wide crawls, history and exports are on paid plans: Lite $49, Standard $99, Advanced $279 a month, with a 7-day trial.

seomator.com

Also worth bookmarking

Google Search Console

Free for verified owners · Google account and verified ownership

Google's own record of what it crawled, indexed and excluded, and the queries you really show up for.

Your verified sites only. It reports problems but does not audit page content.

PageSpeed Insights

Free, any URL · None

LCP, INP and CLS from real Chrome users where a page has enough traffic, plus a Lighthouse lab test.

Speed first. Its SEO section is a short Lighthouse checklist.

Bing Webmaster Tools

Free for verified owners · Account and verified ownership

Bing's crawl and index data plus a Site Scan crawler. Bing's index also grounds Microsoft Copilot.

Your verified sites only, and scans queue rather than run on demand.

HubSpot AI Search Grader

Free, after a short form · None

How ChatGPT, Perplexity and Gemini describe your brand: sentiment, share of voice and market position.

Brand perception only. It does not look at your site's code, robots.txt or schema.

What a free audit score won't tell you

  1. 01

    An A+ grade can hide a broken page

    Most scores are a checklist: is there a title, an H1, alt text. A page can score A+ while its content only appears after JavaScript runs, which many crawlers never see, or while robots.txt blocks every AI crawler.

  2. 02

    Free backlink and keyword data is always capped

    A backlink index or a keyword volume database means crawling and storing much of the web, continuously. Free tools that offer it, like Ahrefs Webmaster Tools, limit it to sites you own. Everything a page itself reveals, its tags, links, schema and crawler rules, can be audited free.

  3. 03

    Ready for Google is not ready for AI search

    AI answer engines use their own crawlers, often skip JavaScript, and quote self-contained passages rather than ranking whole pages. A page can rank on Google and still be invisible to ChatGPT or Perplexity.

Checking AI search readiness for free

Most audit tools started out checking for Google, and some now add AI search checks (Semrush's Site Audit does). Whichever tool you use, these four things decide whether ChatGPT, Perplexity or Google AI Overviews can cite a page. The GEO audit checklist covers the full list.

AI crawler access

Search bots like OAI-SearchBot, PerplexityBot and Claude-SearchBot decide whether you can be cited. Training bots like GPTBot and Google-Extended do not. Block the second kind if you like, never the first.

Content in the server HTML

Most AI crawlers do not run JavaScript. If the copy only appears after hydration, they read an empty page.

Answer-first passages

Short paragraphs under clear headings, lists and tables give AI engines standalone passages they can quote.

Connected schema

JSON-LD that ties the Organization, its people and its products together tells an engine which entity a page is about.

Do not count on llms.txt. An Ahrefs study of 137,210 sites found that 97% of llms.txt files got no requests at all in May 2026. It takes a few minutes to add, so it does no harm, but crawler access and server-rendered content matter far more.

A free audit workflow that covers everything

Four free tools, in this order, cover what a paid suite's audit does. Work through the full SEO audit checklist alongside if you want every check explained.

  1. 01

    Audit your most important pages with IMVASA

    Homepage, pricing, top product and top blog post. Fix what the report ranks first, using the fix prompt in your editor or assistant, then run it again.

  2. 02

    Crawl the whole site with Screaming Frog or Ahrefs Webmaster Tools

    Screaming Frog for up to 500 URLs of any site; Ahrefs Webmaster Tools for larger sites you own. Look for broken links, redirect chains, missing canonicals and duplicate titles.

  3. 03

    Check what Google indexed in Search Console

    The Page indexing report is Google's own record. No third-party tool can replace it.

  4. 04

    Check real-user speed in PageSpeed Insights

    Field data for LCP, INP and CLS, where your traffic is high enough to have it.

Audit a page for free right now

No signup and no credit card. 206 SEO and AI search checks, ranked by what to fix first, with a report link you can share.

Frequently asked questions

What is the best free SEO audit tool?
It depends on the job. For one page with no account, IMVASA checks SEO and AI search together. For a whole site, Screaming Frog crawls up to 500 URLs free, and Ahrefs Webmaster Tools crawls sites you own. Google Search Console is the only source for what Google actually indexed.
What are some free alternatives to Semrush for SEO auditing?
Ahrefs Webmaster Tools is the closest: free site audits and backlink data for sites you can verify. Screaming Frog's free version crawls 500 URLs of any site. IMVASA audits any single page with no account. Search Console covers your own keywords. Nothing free replaces Semrush's competitor keyword data.
What's a good free SEO audit tool for a SaaS website?
Start with IMVASA on your homepage, pricing and docs pages. SaaS sites are often client-rendered, and IMVASA flags pages whose content is missing from the server HTML, which hides it from many crawlers. Then crawl the full site with Ahrefs Webmaster Tools and watch indexing in Search Console.
Is Screaming Frog free?
Yes, up to 500 URLs per crawl. JavaScript rendering, saved crawls, custom extraction, structured data validation, scheduling and the Search Console and PageSpeed integrations need a licence, which costs €245 a year.
Is Semrush's free account enough for a site audit?
Only for a small site. The free account allows Site Audit on up to 100 pages a month in one project, and 10 analytics reports a day. That is enough to see how Semrush works, but most real sites outgrow it on the first crawl.
Is SEOptimer free?
You can run a one-off audit on SEOptimer's website for free. Saved reports, monitoring and white-label PDFs are on paid plans: DIY SEO at $29, White Label at $39 and White Label & Embedding at $59 a month, each with a 14-day trial.
Can I run a free SEO audit from ChatGPT, Claude or Cursor?
Yes. IMVASA runs a free public MCP server at https://seoaudit.imvasa.dev/mcp. Add it to your assistant and it can run a full audit, list only the failing checks, or reopen an earlier report, with no API key or account.
What is the difference between an SEO audit and a GEO audit?
An SEO audit checks whether Google can crawl, index and rank a page. A GEO audit checks whether AI answer engines like ChatGPT, Perplexity and Google AI Overviews can reach it, understand it and quote it. They share crawlability and structure, then split on AI crawler access, server-rendered content and answer-first writing.

Keep going

SEO audit checklist

Every technical and on-page check, explained.

GEO audit checklist

What AI answer engines need before they cite you.

Free GEO audit tool

Score your AI search visibility on any URL.

Free SEO audit MCP

Run audits from ChatGPT, Claude or Cursor.

Free SEO tools for every site

robots.txt, sitemap.xml and llms.txt builders.