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MSEO Merlin

The SEO plugin that works with Yoast and RankMath — not against them.

BUILT BY DEVEBO · MMXXVI
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Why SEO Merlin

An SEO tool the agency owner would build for themselves.

Three principles drive every product decision: companion to existing tools, no AI markup, fixes that ship — not just diagnoses.

01Principle
0 plugins replaced
You keep your existing setup
Companion, not replacement

We don't compete with Yoast and RankMath. We complete them.

Most SEO tools want to be the only thing installed. That's a sales strategy, not a customer benefit. Our research with 200+ agencies showed the same pattern: they have Yoast or RankMath running and will not switch. They want a tool that respects that decision and fills the gaps neither plugin handles — AI search readiness, structured data depth, and the technical fixes those plugins flag but don't auto-apply.

02Principle
~$0.04
Average cost per full audit
Bring your own keys

We don't resell API access. You pay providers directly.

AI-SEO tools typically charge $99–499/mo and bury the fact that you're paying 3–5× the actual API cost. We took a different bet: you bring your own Anthropic and DataForSEO keys, we give you the tooling, you see exact spend per scan. The plugin license is one-time. The AI cost is whatever your providers charge — which is usually pennies per audit.

03Principle
37 / 43
Checks that fix themselves
Fixes that ship

Diagnosis is cheap. Auto-applying the fix is the work.

Every other audit tool tells you what's wrong and stops there. Of our 43 checks, 37 are auto-fixable from the queue without leaving wp-admin. Every fix is logged, reversible, and shows the exact diff. We treat 'one-click fix' as the floor, not the ceiling — bulk fixes, scheduled fixes, and queue export are all standard.

Versus the field

What you actually pay versus what they charge.

Year 1Year 2Year 3Auto-fixesBYOK
SEO Merlin · Freelancer$199$0$037 / 43Yes
Yoast Premium$99$99$99~6No
RankMath Pro$79$79$79~8No
AIOSEO Pro$199$199$199~10No
Surfer SEO$1,188$1,188$1,1880No
Frase$540$540$5400No

* Pricing as of April 2026. Auto-fix counts based on public documentation.

In practice
“We dropped a $400/mo Surfer subscription and got better technical coverage. The auto-fix queue is the killer feature — diagnoses are cheap.”
Maya Hellström
Founder, Clarity & Co
·01
“It's the first SEO tool that doesn't fight Yoast. We installed it on 23 client sites in an afternoon. Zero conflicts.”
Devon Akinwale
Tech Lead, Maven Digital
·02
“BYOK was the unlock. I see exactly what an audit costs me — usually pennies. No more 'AI tax'.”
Hiroshi Yamamoto
Indie WP developer
·03
“Schema validation alone replaced two paid tools. The reports look like something I'd ship to a client without rebuilding.”
Priya Kapoor
Director, Roost Agency
·04
Closing

The plugin you'll wish
you installed last year.

Start Free →See pricing
Final word

Your site has SEO problems
right now.

Find them in 90 seconds. Fix the auto-fixable ones in another two minutes. Free forever.

Start Free Audit →or browse the docs first
Free forever · No credit card · Installs in under a minute