Resource Hints

developer

GET/v1/domain/resource-hints

Discovers resource hints (preconnect, prefetch, preload, dns-prefetch) configured on a webpage. Reveals third-party dependencies and performance optimization strategies.

What It Does

Parses HTML for link rel="preconnect", "prefetch", "preload", and "dns-prefetch" tags. Identifies which external domains are prioritized, what resources are preloaded, and analyzes the performance optimization strategy.

Why It's Useful

Resource hints reveal critical third-party dependencies and performance priorities. They expose which services a site relies on and provide insights into their performance optimization approach.

Use Cases

Performance Engineer

Performance Analysis

Analyze resource hints to understand performance optimization strategy.

Learn from competitor performance optimizations.

Security Analyst

Third-Party Discovery

Identify critical third-party dependencies from preconnect hints.

Map supply chain dependencies for security assessment.

SEO Specialist

SEO Audit

Verify resource hints are properly configured for Core Web Vitals.

Optimize page performance for better search rankings.

Parameters

Name	Type	Required	Description
`domain`	string	Required	Domain or full URL — accepts `example.com` or `https://example.com/path`.Example: `https://example.com`

Response Fields

Field	Type	Description
`domain`	string	The analyzed domain (bare hostname).
`url`	string	Full URL that was fetched, echoing the protocol used in the request.
`preconnect`	array	Hrefs with preconnect hints (legacy flat form)
`preconnectEntries`	array	Structured preconnect entries: { href, crossorigin, media, source: "html" \| "link-header" }
`prefetch`	array	Resources marked for prefetch (legacy flat form)
`prefetchEntries`	array	Structured prefetch entries with source
`preload`	array	Preload entries: { href, as, type, crossorigin, media, fetchpriority, source }
`dnsPrefetch`	array	Domains with DNS prefetch (legacy flat form)
`dnsPrefetchEntries`	array	Structured dns-prefetch entries with source
`prerender`	array	Pages marked for prerender (legacy; use Speculation Rules)
`prerenderEntries`	array	Structured prerender entries with source
`speculationRules`	object	Modern Speculation Rules API rules parsed from <script type="speculationrules"> — { prerender: [...], prefetch: [...], raw }
`bySource`	object	Count of hints by origin: { html, linkHeader }. Reveals CDN-injected hints
`earlyHintsRecommended`	boolean	True when the CDN supports 103 Early Hints and the origin already publishes Link headers
`duplicates`	array	Hrefs hinted multiple ways (e.g. preload + preconnect, or HTML + Link header) — wasted bytes
`issues`	array	Structured issues: missing `as`, font preload without crossorigin, multiple fetchpriority=high, etc.
`totalCount`	number	Total resource hints found
`recommendations`	array	Optimization suggestions based on web.dev 2026 guidance

Code Examples

cURL

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

JavaScript

const response = await fetch(
  'https://api.edgedns.dev/v1/domain/resource-hints?domain=https%3A%2F%2Fexample.com',
  {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  }
);

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

Python

import requests

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

data = response.json()
print(data)

Read the full Resource Hints guide

Why it matters, real-world use cases, parameters, response fields, and how to call it from Claude, ChatGPT, or Gemini via MCP.

Read the guide →

External References

Learn more about the standards and protocols behind this endpoint.

Web Vitals MDN HTTP Caching

Try This Endpoint

Test the Resource Hints endpoint live in the playground.

Open in Playground Get API Key