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GET
/
v1
/
companies
/
{company_identifier}
/
similar
Find Similar Companies
curl --request GET \
  --url https://api.extruct.ai/v1/companies/{company_identifier}/similar \
  --header 'Authorization: Bearer <token>'
{
  "results": [
    {
      "id": "<string>",
      "domain": "<string>",
      "name": "<string>",
      "short_description": "<string>",
      "full_description": "<string>",
      "products_services": "<string>",
      "use_cases": "<string>",
      "target_audience": "<string>",
      "other_considerations": "<string>",
      "founding_year": 123,
      "employee_count": "<string>",
      "hq_country": "<string>",
      "hq_state_province": "<string>",
      "hq_city": "<string>",
      "hq_full_address": "<string>",
      "social_profiles": {},
      "website_authority": {
        "score": 123,
        "tier": "<string>",
        "tier_label": "<string>"
      },
      "relevance_score": 123
    }
  ],
  "request": {
    "offset": 123,
    "limit": 123,
    "query": "<string>",
    "filters": {
      "include": {
        "size": [],
        "country": [
          "<string>"
        ],
        "city": [
          "<string>"
        ]
      },
      "exclude": {
        "size": [],
        "country": [
          "<string>"
        ],
        "city": [
          "<string>"
        ],
        "domains": [
          "<string>"
        ]
      },
      "range": {
        "founded": {
          "min": 123,
          "max": 123
        }
      }
    },
    "reference_company_id": "<string>"
  },
  "reference_company": {
    "id": "<string>",
    "domain": "<string>",
    "name": "<string>",
    "short_description": "<string>",
    "full_description": "<string>",
    "products_services": "<string>",
    "use_cases": "<string>",
    "target_audience": "<string>",
    "other_considerations": "<string>",
    "founding_year": 123,
    "employee_count": "<string>",
    "hq_country": "<string>",
    "hq_state_province": "<string>",
    "hq_city": "<string>",
    "hq_full_address": "<string>",
    "social_profiles": {},
    "website_authority": {
      "score": 123,
      "tier": "<string>",
      "tier_label": "<string>"
    },
    "relevance_score": 123
  }
}
Prefer POST /v1/companies/{company_identifier}/similar. This GET endpoint is deprecated. It still works and returns identical results, but POST is the recommended default: it takes filters as a JSON object and is not limited by URL length (required for large exclude.domains lists).

​
Overview

Lookalike Search returns companies ranked by similarity to a reference company. Pass a company domain or UUID. Result quality depends heavily on how representative the seed company is.

​
Example request

export EXTRUCT_API_TOKEN="YOUR_API_TOKEN"

curl --get "https://api.extruct.ai/v1/companies/stripe.com/similar" \
  -H "Authorization: Bearer ${EXTRUCT_API_TOKEN}" \
  --data-urlencode 'filters={"include":{"country":["United States"]},"exclude":{"size":["1-10"]}}' \
  --data-urlencode "offset=0" \
  --data-urlencode "limit=20"

​
Key parameters

  • company_identifier (required): Company domain or UUID.
  • filters (optional): JSON string to narrow results.
  • offset (optional): Pagination offset.
  • limit (optional): Page size, up to 250 per request.
Lookalike uses the same filter format as semantic search. See Search Filters Reference.

​
Endpoint behavior

  • Ranking blends what a company does, who it sells to, firmographics, and traffic.
  • filters narrow the result set, but the seed company still determines what “similar” means.
  • Prefer a clear, representative company domain when possible. Use a UUID when you already have one from Extruct.
  • A single request returns at most 250 results. Page with offset to read deeper: paid plans (Starter, Pro) can reach up to 2,000 results per query; the free tier is capped at 25.

​
Success signal

A successful response returns results with company candidates. Reuse results[].domain or results[].id in follow-up workflows.

​
Common errors

​
401 Unauthorized

Check that your header is Authorization: Bearer ${EXTRUCT_API_TOKEN}.

​
404 Not Found

The reference company identifier is not present in the index. Try a known domain from semantic results (results[].domain) or a valid UUID.

​
422 Unprocessable Entity

Most often caused by malformed filters JSON. Validate before sending: 
echo '<filters-json>' | jq empty

Authorizations

​
Authorization
string
header
required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Path Parameters

​
company_identifier
string
required

Reference company UUID or domain.

Query Parameters

​
filters
string | null

JSON string of SearchFilters. Supported keys only: include.size/country/city, exclude.size/country/city/domains, range.founded.min/max.

​
offset
integer | null
​
limit
integer | null

Response

Successful Response

Lookalike search response wrapper.

​
results
CompanySearchResult · object[]
required

Search results

​
request
LookalikeRequestInfo · object
required

Request parameters echo

​
reference_company
CompanySearchResult · object

Reference company for lookalike searches