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Inspect any website with a comprehensive analysis similar to browser DevTools. Get HTTP headers, cookies, response time, metadata, and all loaded resources including scripts, stylesheets, images, and links.

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API Endpoint

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GET /devtools

Perform a comprehensive inspection of a webpage by providing its URL.
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url
string
required
The URL of the webpage to inspect. Must be a valid HTTP or HTTPS URL.

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Example Request

curl "https://your-worker.workers.dev/devtools?url=https://www.cloudflare.com"

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Response Structure

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success
boolean
Indicates if the request was successful
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data
object
The comprehensive inspection results
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data.url
string
The requested URL
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data.statusCode
number
HTTP response status code (e.g., 200, 404, 500)
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data.responseTimeMs
number
Response time in milliseconds (rounded)
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data.headers
object
HTTP response headers as key-value pairs. All header names are lowercase.
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data.cookies
string[]
Array of Set-Cookie header values
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data.metadata
object
Page metadata
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data.metadata.title
string | null
Page title from <title> tag
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data.metadata.description
string | null
Meta description
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data.metadata.canonical
string | null
Canonical URL if specified
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data.scripts
string[]
Array of unique absolute URLs of JavaScript files loaded via <script src="...">
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data.stylesheets
string[]
Array of unique absolute URLs of CSS files loaded via <link rel="stylesheet">
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data.images
string[]
Array of unique absolute URLs of images from <img src="...">
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data.links
string[]
Array of unique absolute URLs from <a href="...">. Excludes anchor links (#) and javascript: links.

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Example Response

{
  "success": true,
  "data": {
    "url": "https://www.cloudflare.com",
    "statusCode": 200,
    "responseTimeMs": 245,
    "headers": {
      "content-type": "text/html; charset=utf-8",
      "server": "cloudflare",
      "cf-ray": "8a1b2c3d4e5f6g7h-SJC",
      "cache-control": "max-age=3600",
      "content-encoding": "gzip",
      "vary": "Accept-Encoding"
    },
    "cookies": [
      "__cflb=0123456789abcdef; Path=/; HttpOnly; Secure; SameSite=Lax"
    ],
    "metadata": {
      "title": "Cloudflare - The Web Performance & Security Company",
      "description": "Here at Cloudflare, we make the Internet work the way it should.",
      "canonical": "https://www.cloudflare.com/"
    },
    "scripts": [
      "https://www.cloudflare.com/js/main.js",
      "https://ajax.cloudflare.com/cdn-cgi/scripts/analytics.js"
    ],
    "stylesheets": [
      "https://www.cloudflare.com/css/main.css",
      "https://www.cloudflare.com/css/responsive.css"
    ],
    "images": [
      "https://www.cloudflare.com/img/logo.svg",
      "https://www.cloudflare.com/img/hero-image.png"
    ],
    "links": [
      "https://www.cloudflare.com/products/",
      "https://www.cloudflare.com/plans/",
      "https://developers.cloudflare.com/"
    ]
  }
}

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Error Responses

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Invalid URL

{
  "success": false,
  "error": "Missing or invalid query parameter: url",
  "code": "INVALID_URL"
}

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Fetch Error

{
  "success": false,
  "error": "HTTP 404",
  "code": "FETCH_ERROR"
}

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Deployment

1

Clone the repository

git clone https://github.com/your-org/cloudflare-experiments
cd cloudflare-experiments/experiments/website-devtools-inspector
2

Install dependencies

npm install
3

Test locally

npm run dev
The API will be available at http://localhost:8787
4

Deploy to Cloudflare Workers

npm run deploy

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Use Cases

  • Performance Monitoring: Track response times and identify slow-loading resources
  • Security Audits: Analyze headers, cookies, and security configurations
  • Asset Analysis: Discover all external dependencies and third-party scripts
  • SEO Audits: Inspect metadata and canonical URLs
  • Debugging: Investigate website structure and loaded resources
  • Competitive Analysis: Understand technology stack and external services used
  • Compliance Checks: Verify cookie policies and header configurations

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Technical Details

  • Built with Hono framework
  • Runs on Cloudflare Workers
  • Custom User-Agent: Cloudflare-Experiments-DevtoolsInspector/1.0
  • Configurable fetch timeout
  • Maximum HTML size limit to prevent memory issues
  • All relative URLs resolved to absolute URLs
  • Response time measured from request start to completion

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Inspection Details

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Headers

  • All response headers are captured
  • Header names are normalized to lowercase
  • Includes Cloudflare-specific headers (cf-ray, cf-cache-status, etc.)

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Cookies

  • Extracted from Set-Cookie response headers
  • Preserves all cookie attributes (Path, HttpOnly, Secure, SameSite)
  • Multiple cookies are returned as separate array entries

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Resources

  • Scripts: Extracted from <script src="...">
  • Stylesheets: Extracted from <link rel="stylesheet" href="...">
  • Images: Extracted from <img src="...">
  • Links: Extracted from <a href="...">
  • All URLs are deduplicated and resolved to absolute URLs

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Response Time

  • Measured in milliseconds from request initiation to response completion
  • Includes network latency and initial content download
  • Rounded to the nearest millisecond