Free SEO Audit API - Check Any Website's SEO in Seconds

2026-03-14 | Tags: api, seo, webdev, marketing

Free SEO Audit API - Check Any Website's SEO in Seconds

Running an SEO audit usually means signing up for expensive tools like Ahrefs, SEMrush, or Screaming Frog. But what if you just need a quick programmatic check? What if you want to integrate SEO checking into your CI/CD pipeline or monitoring system?

Our SEO Audit API gives you a comprehensive analysis with a single API call. No signup, no API key required for basic usage.

Quick Start

curl "https://51-68-119-197.sslip.io/api/seo?url=https://example.com"

The response includes:

What Gets Checked

Meta Tags (Critical for Rankings)

The API checks for the presence and quality of:

Tag What We Check
<title> Present, length (50-60 chars optimal), keyword placement
<meta description> Present, length (150-160 chars optimal)
<link rel="canonical"> Present, self-referencing, matches URL
<meta robots> Index/noindex, follow/nofollow directives
OG tags og:title, og:description, og:image, og:url
Twitter cards twitter:card, twitter:title, twitter:description

Heading Structure

Proper heading hierarchy matters for both SEO and accessibility:

{
  "headings": {
    "h1": ["Main Page Title"],
    "h2": ["Section 1", "Section 2"],
    "h3": ["Subsection A", "Subsection B"],
    "issues": ["Multiple H1 tags found", "H3 used without preceding H2"]
  }
}

Image Optimization

Every image without alt text is a missed SEO opportunity:

{
  "images": {
    "total": 15,
    "missing_alt": 3,
    "missing_alt_urls": [
      "/images/hero.jpg",
      "/images/banner.png"
    ]
  }
}

Structured Data

The API detects JSON-LD, microdata, and RDFa schemas — critical for rich snippets in search results.

Use Cases

CI/CD SEO Regression Testing

Add SEO checks to your deployment pipeline. Catch issues before they reach production:

# In your CI/CD pipeline
RESULT=$(curl -s "https://51-68-119-197.sslip.io/api/seo?url=https://staging.yoursite.com")
MISSING_ALT=$(echo $RESULT | jq '.images.missing_alt')
if [ "$MISSING_ALT" -gt 0 ]; then
  echo "WARNING: $MISSING_ALT images missing alt text"
fi

Bulk Site Monitoring

Monitor SEO health across multiple pages or sites:

import requests
import json

urls = [
    "https://yoursite.com",
    "https://yoursite.com/blog",
    "https://yoursite.com/products",
]

for url in urls:
    resp = requests.get(f"https://51-68-119-197.sslip.io/api/seo?url={url}")
    data = resp.json()
    title_len = len(data.get("meta", {}).get("title", ""))
    print(f"{url}: title={title_len} chars, images_no_alt={data.get('images', {}).get('missing_alt', 0)}")

Agency Client Audits

Run quick audits on client sites without installing any tools:

curl "https://51-68-119-197.sslip.io/api/seo?url=https://client-site.com" | jq '.'

Combine with Other APIs

Full Website Audit

Pair SEO with our other APIs for a comprehensive site analysis:

# SEO audit
curl "https://51-68-119-197.sslip.io/api/seo?url=https://example.com"

# Dead link check
curl "https://51-68-119-197.sslip.io/api/deadlinks?url=https://example.com"

# Performance metrics
curl "https://51-68-119-197.sslip.io/api/perf?url=https://example.com"

# Or use our bundle endpoint for all-in-one:
curl "https://51-68-119-197.sslip.io/api/audit?url=https://example.com&seo=true"

Rate Limits

Feature Anonymous Free API Key
Daily requests 5 50
Rate limit 1 req/10s 1 req/30s window

Get a free API key at our API docs page — instant, no email required.

Why Not Just Use Google Lighthouse?

Lighthouse is excellent but has limitations for programmatic use:

  1. Requires Chrome/Node.js — heavy dependency for a simple check
  2. Slow — full Lighthouse audit takes 30-60 seconds
  3. No API — you need to host your own instance or use PageSpeed Insights (rate-limited)
  4. Overkill — if you just need meta tag and heading checks, Lighthouse is too much

Our API focuses on the SEO-specific checks that matter most for rankings, with a response time under 5 seconds.

Try It Now

Use our interactive SEO audit tool to check any website instantly.

Or call the API:

curl "https://51-68-119-197.sslip.io/api/seo?url=https://your-site.com" | jq '.'