37 Audits
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CDN Coverage Checker

Performance Checker

Checks if your website content is served through a CDN

PerformanceDeliveryResilience
30 credits
Per check
~30 seconds
Average runtime
Active
Status

How it works

Analyzes whether your website and its static assets (CSS, JavaScript, images, fonts, videos) are being served through a Content Delivery Network (CDN). This checker examines the main HTML document and all first-load assets to determine CDN coverage across your entire website.

What this checker validates

What This Checker Analyzes

The CDN Coverage Checker performs a comprehensive analysis of your website's content delivery infrastructure by:

HTML Document Analysis

  • Fetches the main HTML document from the provided URL

  • Checks if the HTML itself is served through a CDN by analyzing:

    • Hostname patterns (e.g., .cloudfront.net, .fastly.net, .akamai.net)

    • HTTP response headers (e.g., cf-cache-status, x-amz-cf-id, x-cache)

    • CNAME DNS resolution chains to detect CDN endpoints

Static Asset Discovery

The checker automatically discovers and analyzes all first-load static assets including:

  • CSS files ()

  • JavaScript files (

Output Documentation

Output Documentation

StatusConditionDescription
✅ SuccessAll content served via CDNBoth the HTML document and all discovered static assets (CSS, JS, images, fonts, videos) are served through a CDN. This is the optimal configuration for performance and scalability.
⚠️ WarningPartial CDN coverageEither:
• Only static assets are served via CDN while HTML is not
• Mixed coverage where some assets use CDN and others don't
This indicates room for optimization in your CDN strategy.
❌ FailNo CDN coverageNeither the HTML document nor any of the discovered static assets are served through a CDN. This configuration may result in poor performance, especially for users geographically distant from your origin server.

Detailed Analysis Data

The checker provides comprehensive data including:

  • HTML CDN Status: Whether the main document uses CDN

  • Asset Breakdown: Individual CDN status for each discovered asset

  • Coverage Statistics: Total assets found vs. assets served via CDN

  • Detection Methods: How CDN usage was identified (hostname, headers, or CNAME resolution)

Risks and Considerations

Risks of Poor CDN Coverage

Performance Impact

  • Increased Load Times: Without CDN distribution, users far from your origin server experience significantly slower page loads

  • Higher Time to First Byte (TTFB): Each request travels the full distance to your origin server

  • Poor User Experience: Slow-loading assets create frustrating user experiences, especially for mobile users

Scalability Issues

  • Origin Server Overload: All traffic hits your origin server directly, creating potential bottlenecks

  • Bandwidth Costs: Higher bandwidth usage at your origin location increases hosting costs

  • Geographic Performance Disparity: Users in different regions experience vastly different performance

Business Consequences

  • SEO Impact: Google's Core Web Vitals consider loading speed as a ranking factor

  • Conversion Rate Loss: Studies show that even 100ms delays can reduce conversion rates

  • Competitive Disadvantage: Slower websites lose users to faster competitors

  • Mobile Performance: Poor CDN coverage particularly impacts mobile users on slower connections

Availability Risks

  • Single Point of Failure: No geographic redundancy if your origin server experiences issues

  • DDoS Vulnerability: Direct exposure of origin server to all traffic without CDN protection

  • Limited Caching: Missing out on edge caching benefits that reduce server load

Ready to start auditing?

Add this checker to your monitoring setup and start identifying issues on your websites today.

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