SEO Score API is a REST API that runs 54 SEO checks on any URL and returns a score from 0 to 100 with a letter grade — for free. The free tier gives you 5 audits per day with full results across every category: meta tags, technical SEO, performance, social signals, and accessibility. No credit card required.

A free SEO score checker is a tool that analyzes your website and returns an objective measurement of its search optimization health. Unlike manual audits that take hours, an API-based checker returns results in under 5 seconds.

What Does the Free SEO Checker Include?

The free tier includes all 54 checks across five scoring categories — the same checks available on paid plans. There are no locked features or hidden paywalls on the audit results themselves. The only limit is 5 audits per day.

The five scoring categories are:

  • Meta — title tag, meta description, canonical, robots, viewport
  • Technical — H1, structured data (JSON-LD), sitemap detection, hreflang, HTTPS
  • Performance — server response time, compression, resource loading, redirect count
  • Social — Open Graph title/description/image, Twitter Card tags
  • Accessibility — image alt text, ARIA landmarks, language attribute, form labels

Each category returns a sub-score (0–100) and letter grade so you can see exactly where your site excels and where it falls short.

How Do You Get a Free SEO Score?

You get a free SEO score by signing up for an API key, then making a single GET request to the audit endpoint. The entire process takes under two minutes.

Step 1 — Sign up for a free key:

curl -X POST https://seoscoreapi.com/signup \
  -H "Content-Type: application/json" \
  -d '{"email": "you@example.com"}'

Step 2 — Run your first audit:

curl "https://seoscoreapi.com/audit?url=https://yoursite.com" \
  -H "X-API-Key: YOUR_KEY_HERE"

Step 3 — Read your results:

{
  "url": "https://yoursite.com",
  "score": 76,
  "grade": "B",
  "priorities": [
    { "issue": "Missing og:image tag", "severity": "warning" }
  ]
}

The priorities array lists every individual check failure with a plain-English description of what to fix.

What Does the Audit Actually Check?

The audit covers 54 individual checks. Here are some of the most impactful ones:

Meta checks:

  • Title tag present and within 50–60 characters
  • Meta description present and within 150–160 characters
  • Canonical URL set correctly
  • Viewport meta tag present (mobile optimization)

Technical checks:

  • Single H1 tag present
  • JSON-LD structured data detected
  • HTTPS enforced
  • XML sitemap detectable

Performance checks:

  • Server response time under 600ms
  • GZIP or Brotli compression enabled
  • No 4xx or 5xx response codes

Social checks:

  • og:title, og:description, og:image all present
  • Twitter Card meta tags present

Accessibility checks:

  • All images have alt attributes
  • Page has a lang attribute on <html>
  • Heading hierarchy is logical (H1 → H2 → H3)

Free vs. Paid: What Is the Difference?

Feature Free Starter ($5/mo) Basic ($15/mo) Pro ($39/mo)
Audits per day 5 200/mo 1,000/mo 5,000/mo
Requests per minute 2 10 30 60
Core 54 checks Yes Yes Yes Yes
SXO, AEO & AIO scores No Yes Yes Yes
Batch audits No Yes Yes Yes
URL monitoring No 5 URLs 10 URLs 25 URLs

For one-off checks, competitor research, or testing integrations, the free tier is all you need. For agencies running audits across client portfolios, paid plans provide the volume and extended scoring.

How Can I Use the Free Checker in My Projects?

You can use the free SEO checker in any project that can make HTTP requests. Common use cases include:

  1. Pre-launch checks — audit your site before going live to catch missing meta tags
  2. Competitor research — score competitor URLs to identify gaps
  3. CMS testing — verify that theme or plugin changes didn't break SEO elements
  4. Portfolio reviews — quickly assess the SEO health of sites you're pitching on
  5. CI/CD gates — fail deployments if the score drops below a threshold

The Python SDK makes integration especially fast:

from seoscoreapi import signup, audit

key = signup("you@example.com")
result = audit("https://yoursite.com", api_key=key)
print(f"Score: {result['score']} ({result['grade']})")

Is the Free SEO Checker Accurate?

Yes. The free tier uses the same analysis engine as all paid plans — headless Chromium via Playwright, which renders JavaScript before scoring. This means the audit sees your page the way Google's crawler does, not just the raw HTML source.

The score reflects technical and on-page factors. It does not measure backlinks, domain authority, or content quality — those require separate tools.

Frequently Asked Questions

Is the free SEO checker really free?

Yes, the free tier is genuinely free with no credit card required. You get 5 audits per day, access to all 54 checks, and full JSON results. The only limits compared to paid plans are audit volume and access to SXO/AEO/AIO extended scoring, batch auditing, and URL monitoring.

Do I need to install anything to use the free checker?

No installation is required. The SEO Score API is a REST API — you make HTTP requests from any language, terminal, or tool. There is also a Python SDK (pip install seoscoreapi) and a Node.js SDK (npm install seoscoreapi) if you prefer a client library.

How long does a free SEO audit take?

A free SEO audit typically completes in 2–5 seconds. Pages with heavy JavaScript or slow server responses may take up to 10 seconds. The API uses headless Chromium to render the page before scoring, which accounts for most of the processing time.

Can I check any website's SEO score for free?

Yes. You can audit any publicly accessible URL — your own site, competitor sites, or client sites. URLs behind login walls or on private networks cannot be audited.

What is the difference between free and paid plans?

The free plan limits you to 5 audits per day and 2 requests per minute. Paid plans start at $5/month for 200 audits and add SXO/AEO/AIO extended scores, batch auditing (multiple URLs in one request), and URL monitoring with score-drop alerts.

How do I upgrade from the free plan?

Log in to your developer portal at seoscoreapi.com/portal with your registered email. From there you can upgrade to any paid plan via Stripe. Your API key stays the same — limits are updated immediately on upgrade.