Core Web Vitals

What It Does

Queries the CrUX API for real-world performance data (p75 values for LCP, INP, CLS, TTFB, FCP with histogram distributions) and simultaneously performs server-side analysis: measures TTFB directly, scans HTML for render-blocking resources, images without dimensions (CLS risk), missing preload/preconnect hints (LCP risk), synchronous scripts and third-party script domains (INP risk), and resource hint usage. Produces a composite score (0-100) combining field data (60%) and server-side analysis (40%), with a letter grade and prioritized recommendations. Even when CrUX data is unavailable (smaller sites), the server-side analysis still provides actionable diagnostics.

Why It's Useful

Core Web Vitals are a confirmed Google ranking factor. This endpoint goes beyond raw CrUX data by identifying specific optimization opportunities in your HTML — render-blocking resources slowing LCP, missing image dimensions causing CLS, and excessive third-party scripts affecting INP. Provides value even for sites without CrUX data by analyzing server response time and HTML structure.

Use Cases

Parameters

Response Fields

Code Examples

curl "https://api.edgedns.dev/v1/domain/web-vitals" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d "domain=example.com"

const response = await fetch(
  'https://api.edgedns.dev/v1/domain/web-vitals?domain=example.com',
  {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  }
);

const data = await response.json();
console.log(data);

import requests

response = requests.get(
    'https://api.edgedns.dev/v1/domain/web-vitals',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={
    'domain': 'example.com'
    }
)

data = response.json()
print(data)

Related Endpoints

External References

Learn more about the standards and protocols behind this endpoint.