Mobile-Friendly¶

Fetch a URL and report a static mobile-friendliness verdict based on three signals:

1. Viewport meta — is <meta name="viewport"> present, and does it include width=device-width?
2. Font sizes — any font-size declarations in <style> blocks or inline style="" attributes that fall below the readable threshold (12px / 9pt).
3. Media queries — count of @media rules in inline CSS and <link media="..."> tags (excluding print).

This is a fast, no-headless-browser check — perfect for crawl-time pre-screening, CI gates on preview deploys, or running across thousands of URLs cheaply. It does not render pages or run JavaScript, so SPAs that hydrate their viewport tag at runtime won't be detected.

For full on-page SEO signals see /v1/seo/audit.

Endpoint¶

GET /v1/seo/mobile-friendly

Base URL: https://seo.toolkitapi.io

Query Parameters¶

Response Fields¶

Font-size detection¶

Font-size warnings are emitted for declarations that fall below the readable threshold:

• px units smaller than 12px
• pt units smaller than 9pt

Both <style> block CSS and inline style="font-size:..." attributes are scanned. Inline scanning is capped at the first 50 elements to keep the check fast on large pages. Up to 20 issues are returned.

Examples¶

curl¶

curl -G "https://seo.toolkitapi.io/v1/seo/mobile-friendly" \
  -H "x-api-key: $TOOLKIT_API_KEY" \
  --data-urlencode "url=https://example.com"

Python¶

import requests

resp = requests.get(
    "https://seo.toolkitapi.io/v1/seo/mobile-friendly",
    params={"url": "https://example.com"},
    headers={"x-api-key": API_KEY},
    timeout=30,
)
data = resp.json()

if not data["is_mobile_friendly"]:
    print(f"❌ {data['url']} not mobile-friendly")
    if not data["has_responsive_meta"]:
        print(f"  - viewport: {data['viewport_meta'] or '(missing)'}")
    for issue in data["font_size_issues"]:
        print(f"  - {issue}")
    if not data["has_media_queries"]:
        print("  - no CSS media queries detected")
else:
    print(f"✅ {data['url']} looks mobile-friendly "
          f"({data['media_query_count']} media queries)")

JavaScript¶

const url = new URL("https://seo.toolkitapi.io/v1/seo/mobile-friendly");
url.searchParams.set("url", "https://example.com");

const resp = await fetch(url, {
  headers: { "x-api-key": process.env.TOOLKIT_API_KEY },
});
const data = await resp.json();

if (!data.is_mobile_friendly) {
  console.warn(`Not mobile-friendly: ${data.url}`, {
    viewport: data.viewport_meta,
    issues: data.font_size_issues,
    mediaQueries: data.media_query_count,
  });
}

Example Response¶

{
  "url": "https://example.com",
  "is_mobile_friendly": false,
  "viewport_meta": "width=device-width, initial-scale=1",
  "has_viewport": true,
  "has_responsive_meta": true,
  "font_size_issues": [
    "Small font-size: 10px (minimum 12px recommended)",
    "Inline small font-size: 11px on <span>"
  ],
  "has_media_queries": true,
  "media_query_count": 6
}

In the example above, the viewport is correct and CSS uses media queries — but two font-size declarations dip below 12px, so the overall verdict flips to false. Address the small fonts and the next call will return is_mobile_friendly: true.

Notes¶

• The check is HTML/CSS-only — no headless browser, no JS execution. Sites that hydrate their viewport meta from JavaScript will look like they're missing it.
• font_size_issues is capped at 20; on a page with hundreds of small fonts you'll see the first 20.
• media_query_count is a smoke test, not a coverage metric — having one media query rarely makes a page actually responsive, but having zero is a strong signal it isn't.
• Each call goes through the same SSRF guard as /v1/seo/audit; private/loopback targets are rejected with 400.