Get Associated Domains

Discover domains related to a given domain through acquisition history, certificate transparency logs, and WHOIS records. Returns associated domains with evidence of their relationship.

GET /v1/domain/associated

Get Associated Domains

cURL

curl --request GET \
  --url https://api.projectdiscovery.io/v1/domain/associated \
  --header 'X-API-Key: <api-key>'

200

{
  "domain": "<string>",
  "results": [
    {
      "domain": "<string>",
      "sources": [
        "<string>"
      ],
      "evidence": {
        "acquired_company": "<string>",
        "acquired_date": "<string>",
        "acquirer_name": "<string>",
        "active": true,
        "as_name": "<string>",
        "as_number": 123,
        "cert_common_name": "<string>",
        "cert_expiry_date": "<string>",
        "cert_issued_date": "<string>",
        "cert_issuer": "<string>",
        "cert_org_name": "<string>",
        "cert_serial": "<string>",
        "crunchbase_url": "<string>",
        "expiry_date": "<string>",
        "location": "<string>",
        "orgname": "<string>",
        "probe": "<string>",
        "registrant_org": "<string>",
        "registrar": "<string>",
        "registration_date": "<string>",
        "search_identifier": "<string>",
        "status_code": 123,
        "subdomain_count": 123,
        "title": "<string>",
        "update_date": "<string>",
        "whois_server": "<string>"
      }
    }
  ],
  "sources": [
    "<string>"
  ],
  "sources_count": {},
  "unique_count": 123,
  "limit": 123,
  "page": 123,
  "total_count": 123,
  "total_pages": 123
}

This endpoint discovers domains related to a given domain through multiple intelligence sources: acquisition history, certificate transparency logs, and WHOIS records.

Default Behavior: When called without the domain parameter, returns associated domains for all your verified domains. Optionally provide a domain parameter to query associated domains for a specific domain.

Result Limits: Results are limited to 10 associated domains per query. Enterprise plans include full results with pagination support. Contact sales to access complete results.

Retrieve your API key from Settings → API Key in the ProjectDiscovery Cloud Platform.

Discovery Sources

The Associated Domains API correlates data from three primary sources:

Source	Description
acquisition_history	Corporate subsidiaries and acquired companies from business intelligence sources
certificate_history	SSL/TLS certificate transparency logs revealing shared infrastructure
whois_history	Domain registration records identifying common ownership

Example Requests

Get all associated domains

curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com" \
  -H "X-Api-Key: YOUR_API_KEY"

Filter by specific source

# Only certificate-based associations
curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com&source=certificate_history" \
  -H "X-Api-Key: YOUR_API_KEY"

# Multiple sources
curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com&source=acquisition_history,whois_history" \
  -H "X-Api-Key: YOUR_API_KEY"

Filter by liveness

# Only active/reachable domains
curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com&active=true" \
  -H "X-Api-Key: YOUR_API_KEY"

Paginated results

curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com&limit=50&page=1&sort=subdomain_count" \
  -H "X-Api-Key: YOUR_API_KEY"

Raw output (plain text)

# Get just domain names, one per line (useful for piping to other tools)
curl -X GET "https://api.projectdiscovery.io/v1/domain/associated?domain=meta.com&raw=true" \
  -H "X-Api-Key: YOUR_API_KEY"

Related Resources

• Associated Domains Discovery Guide - Comprehensive feature documentation
• Asset Discovery Overview - Platform asset management capabilities

Authorizations

X-API-Key · string · header · required

Headers

X-Team-Id · string

Query Parameters

domain · string

Domain name to fetch associated domains. If omitted, returns associated domains for all your verified domains.

source · string

Comma-separated source filter (acquisition_history, certificate_history, whois_history)

active · boolean

Filter by liveness (true=alive, false=unreachable)

sort · enum<string>

Sort results

Available options: active, domain, source, subdomain_count, update_date

limit · integer

Maximum results per page (pagination). If omitted, returns all.

page · integer

Page number (pagination, starts at 1)

raw · boolean

If true, returns plain text list (one domain per line)

Response

200

application/json

Associated domains response

domain · string · required

Queried domain

results · AssociatedDomainResult · object[] · required

List of associated domains

Show child attributes

sources · string[] · required

List of sources used in the query

sources_count · object

Count of results per source

Show child attributes

unique_count · integer

Unique associated domains count

limit · integer

Maximum results per page when paginated

page · integer

Current page when paginated

total_count · integer

Total associated domains when paginated

total_pages · integer

Total pages when paginated