API Documentation | WebsitesUsing

Authentication

All API requests require a Bearer token in the Authorization header. You can generate an API key from your dashboard (requires Pro or Team plan).

# Include your API key in every request
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://websitesusing.com/api/v1/domain?d=shopify.com"

Base URL

https://websitesusing.com/api/v1

Endpoints

GET/api/v1/domain

Look up a single domain and get its complete technology profile, including detected technologies, DNS records, SSL certificate, HTTP headers, and more.

Parameters

Name	Type	Description
`domain` or `d`required	string	Domain name to look up (e.g., `shopify.com`)

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://websitesusing.com/api/v1/domain?d=shopify.com"

Example Response

{
  "domain": "shopify.com",
  "scanned_at": "2026-02-17T00:44:20Z",
  "detected_technologies": [
    {
      "name": "Cloudflare",
      "category": "Web Server",
      "confidence": "High",
      "evidence": "HTTP header"
    },
    // ... more technologies
  ],
  "dns": { /* A, CNAME, MX, TXT records */ },
  "ssl": { /* certificate details */ },
  "headers": { /* HTTP response headers */ }
}

GET/api/v1/count

Count how many domains use a specific technology. Optionally filter by country (TLD).

Parameters

Name	Type	Description
`tech`required	string	Technology name (e.g., `shopify`, `wordpress`)
`country`optional	string	TLD/country filter (e.g., `de`, `uk`, `com`)

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://websitesusing.com/api/v1/count?tech=shopify"

Example Response

{
  "count": 1199871
}

With Country Filter

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://websitesusing.com/api/v1/count?tech=shopify&country=de"

// Response
{ "count": 25376 }

GET/api/v1/domains

Get a list of domains using a specific technology. Use limit to control how many results are returned.

Parameters

Name	Type	Description
`tech`required	string	Technology name
`country`optional	string	TLD/country filter
`limit`optional	integer	Maximum domains to return (default: all)

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://websitesusing.com/api/v1/domains?tech=shopify&limit=5"

Example Response

{
  "domains": [
    "allbirds.com",
    "gymshark.com",
    "fashionnova.com",
    "colourpop.com",
    "kyliecosmetics.com"
  ],
  "count": 5
}

Rate Limits

API call limits are enforced per calendar month and depend on your plan.

Starter

—

No API access

Pro

10,000

calls / month

Team

Unlimited

calls / month

Error Codes

The API returns standard HTTP status codes with a JSON error message.

Status	Meaning	Response
`400`	Bad Request	Missing required parameter
`401`	Unauthorized	Missing or invalid API key
`403`	Forbidden	Your plan doesn't include API access
`404`	Not Found	Domain not found in our database
`429`	Too Many Requests	Monthly API call limit exceeded

// Example error response
{
  "error": "API key required"
}

Get Started

Create an account and subscribe to a Pro or Team plan to get your API key.

View Plans & Pricing