Block Companies

POST/v2/blocklist/companies/add

Adds up to 1,000 company domains to the block list and answers every item in added, already_blocked or invalid. A domain or website URL is cleaned to its bare host. A repeat lands in already_blocked. Safe to retry: a repeat never writes a second entry. Free, no credits; spends no rate-limit units, but counts against the per-second window of the search bucket. Blocked people and companies are left out of people and company search, people and company enrich, email find and suggestions in this workspace, within 15 seconds. Saving a person by id and email verify are not filtered by workspace block lists, and blocked domains that resolve to more than 10,000 companies are only partly excluded from people search. Any member or API key of the workspace may call it; a credential that belongs to no workspace answers 403.

Body parameters

dataobject[]required

The domains to block, 1 to 1,000.

Field	Type	Description
`domain`	stringrequired	A domain or a website URL, cleaned to its bare host (`https://www.Acme.com/x` -> `acme.com`). A value that is not a domain goes to `invalid` (`invalid_format`). max length: 200. Example: `"acme.com"`
`identifier`	string	Your key for this item, echoed in the answer. Defaults to the item index. max length: 200.

Responses

200 Every item, in one of the three buckets; the item counts in metadata.
400 Invalid body (VALIDATION_ERROR): missing_field (data), out_of_range (no items, more than 1,000, or a string over 200 characters), wrong_type, unknown_field (with allowed_fields), or conflicting_fields (one identifier on two different items, listed in payload.conflicts). An item that is only unusable lands in invalid instead.
401 Missing, unknown or inactive credentials (UNAUTHORIZED).
403 The credential belongs to no workspace (FORBIDDEN, workspace_required).
409 The add would take the list past its cap of 100,000 companies (CONFLICT, limit_reached, with payload.limit and payload.current_count). Nothing was written.
429 Over the per-second window of the search bucket (RATE_LIMIT). Sent only where rate-limit enforcement is on; wait Retry-After seconds.
500 Unexpected server error; also, rarely, a concurrent change of the same entries. Safe to retry.

For error handling see Errors. Response objects are described in Person object and Company object.

curl --request POST \
  --url https://api.getprospect.com/v2/blocklist/companies/add \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: YOUR_API_KEY' \
  --data '
{
  "data": [
    {
      "domain": "https://www.Acme.com/about",
      "identifier": "a"
    },
    {
      "domain": "acme.com",
      "identifier": "b"
    },
    {
      "domain": "initech.com",
      "identifier": "c"
    },
    {
      "domain": "not a domain",
      "identifier": "d"
    }
  ]
}
'

Response

{
  "success": true,
  "data": {
    "added": [
      {
        "identifiers": [
          "a",
          "b"
        ],
        "blocked_company": {
          "id": "6705a1c2e4b0f1a2b3c4d5e7",
          "domain": "acme.com",
          "created_at": "2026-10-08T09:30:00.000Z"
        }
      }
    ],
    "already_blocked": [
      {
        "identifiers": [
          "c"
        ],
        "blocked_company": {
          "id": "64f0c3d2a1b2c3d4e5f60719",
          "domain": "initech.com",
          "created_at": "2023-09-01T12:00:00.000Z"
        }
      }
    ],
    "invalid": [
      {
        "identifier": "d",
        "code": "invalid_format",
        "field": "domain",
        "reason": "not a domain"
      }
    ]
  },
  "metadata": {
    "timestamp": "2026-10-08T09:30:00.000Z",
    "total": 4,
    "added_count": 2,
    "already_blocked_count": 1,
    "invalid_count": 1
  }
}