A note on bias
We run Krawly, which makes free SEO tools. So we have an obvious incentive to oversell what free tools can do. We're going to try to do the opposite: be specific about where free tools (ours and others) are genuinely competitive with paid platforms, and equally specific about where they are not. If you read this and conclude that you should pay for Ahrefs, that's a fine outcome — Ahrefs is excellent at what it does.
Where free tools are genuinely competitive
On-page SEO audits
Krawly's SEO Analyzer, Heading Analyzer, Meta Tag Validator, and similar checkers do exactly what the on-page audit modules in Ahrefs and SEMrush do. Same checks, same scoring logic, same recommendations. The only difference is that Ahrefs runs them across an entire site automatically; on the free side, you run them one URL at a time.
For a freelancer auditing a 50-page site for one client, the free tools are perfectly adequate and cost nothing. For an agency managing 100 client sites with weekly recrawls, you want the paid platform.
Technical checks (HTTPS, headers, robots, schema)
SSL Checker, HTTP Headers, robots.txt Analyzer, Canonical Checker, Structured Data Validator — these are commodity checks that paid tools also offer but with no meaningful quality difference. The data is deterministic, not curated. No free vs paid distinction.
Schema markup generation
Free FAQ Schema Generator, Product Schema Generator, Breadcrumb Schema Generator produce identical JSON-LD output to anything paid. The Schema.org spec is public; this is not a competitive moat.
YouTube and content research
YouTube Tags Extractor, YouTube Comments, YouTube Channel Analyzer — these tools query YouTube's public APIs. Paid tools that do the same thing (TubeBuddy, vidIQ) wrap the same data with a nicer UI and longer history. If you only need today's data, free is fine.
Where free tools genuinely cannot compete
Backlink databases
Ahrefs, Majestic, and SEMrush have spent billions of dollars over a decade crawling the web to build proprietary link indexes. Ahrefs alone runs the second-most-active web crawler after Google. There is no free equivalent — and there cannot be, because the value comes from the recurring crawl + index infrastructure costs, which only paying customers can fund.
If your work depends on understanding a competitor's backlink profile, you need a paid tool. Krawly does not have a free alternative for this and never will.
Keyword search-volume databases
Same story. Ahrefs and SEMrush buy clickstream data from ISPs and toolbar partners, plus they aggregate years of click-through data, to estimate monthly search volumes. Free tools (including ours via Google Autocomplete) can suggest related keywords but cannot give you accurate search volume numbers. Anyone telling you otherwise is making them up.
If you make decisions based on search volume — which keywords to target, what to invest in — you need a paid keyword tool. Krawly's Keyword Suggestion is genuinely useful for ideation but stops short of volume estimates.
Site-wide automated crawls with historical tracking
Screaming Frog (paid), Sitebulb (paid), Ahrefs Site Audit, SEMrush Site Audit — these crawl your entire site nightly, store the results, and diff against last week's state to flag regressions. Free tools cannot do this for you because the storage and crawl-budget costs are not free.
You can approximate it with Sitemap Health Checker + Broken Link Checker on a manual schedule, but it is genuinely more work.
SERP tracking and rank monitoring
Knowing where your site ranks for "best running shoes" today vs three months ago vs your competitor — paid tools do this every day automatically with rotating proxies. The free version is opening an incognito browser and searching, which doesn't scale.
The honest stack for different budgets
Zero budget: Use Krawly + Google Search Console + Google Analytics 4. This covers about 80% of the diagnostic work most sites ever need. The 20% you cannot do is keyword volume estimation and backlink analysis.
$30/month: Add Ubersuggest or Mangools — entry-level paid tools that give you basic backlink and keyword data. Combined with Krawly for on-page work, this is a competent stack for one-person teams.
$100/month: Drop the entry-level tool and get Ahrefs Lite or SEMrush Pro. The data quality is meaningfully better at this tier, and the backlink index is now actually useful for competitive analysis.
$400+/month: Ahrefs Standard or SEMrush Business. The justification at this price is multiple sites, team access, and historical data. Below this volume, you are paying for capability you do not use.
What I actually use
For client work we run Krawly for every on-page audit (it's our own tool, but we would use the equivalent from someone else if it weren't ours), Ahrefs for backlinks and keyword volume, Screaming Frog for site-wide crawls when the project budget allows it, and Google Search Console for ground-truth data.
Free tools are not a substitute for everything paid tools do. They are a substitute for the on-page diagnostic work that should never have been gated behind a $200/month subscription in the first place.
Recommended free toolset for any small site
If you have one site to audit, here's the order I run them in:
1. SEO Analyzer — overall on-page score
2. Mobile Friendliness Checker — mobile is where rankings live now
3. Page Speed Analyzer — Core Web Vitals signals
4. Heading Analyzer — H1-H6 structure
5. Image SEO Checker — alt text + lazy loading
6. Broken Link Checker — dead outbound links
7. Sitemap Health Checker — sitemap quality
8. Structured Data Validator — schema correctness
9. SSL Checker + HTTP Headers — security and metadata
10. Robots.txt Analyzer — crawl guidance
Done in under an hour. Most pages will surface 5-10 issues, of which 3-5 are quick fixes. That's a meaningful Saturday afternoon of work.
Questions, corrections, complaints
If we've missed something or you disagree with the comparison above, please write to info@krawly.io. We would much rather update this article with a stronger argument than leave a wrong claim in print.