Identify (Reverse Email Lookup)

Use this when you have a list of emails and need to know who each one belongs to — the person, their crustdata_person_id, and basic profile — at bulk scale. Submit a job, then poll or receive a webhook when it finishes. You pay only for the emails that resolve to a person.

Identify vs Enrich. Identify answers “who is this email?” — it returns the matched person’s crustdata_person_id and basic_profile (name, headline, title). If you also need contact data, full employment history, or company IDs per role, use Person Enrich (which also supports reverse lookup by business email).

How it works

Reverse identify is an asynchronous, two-call flow — you submit a job, then fetch the results once it finishes:

Submit your emails

POST /batch/person/identify with your list of emails (or professional_network_profile_urls). You get a batch_id back immediately.

Poll, or wait for a webhook

GET /batch/{batch_id} to check the job status — or pass a webhook_url on submit and we call you when it finishes.

Download the results

Once status is completed, the status response includes a download_url: a gzipped JSONL file with one record per input, valid for 5 days.

Emails already known to Crustdata resolve in seconds. Emails that require real-time retrieval take longer, which is why this endpoint is asynchronous.

Replace YOUR_API_KEY in each example with your actual API key. All requests require the x-api-version: 2025-11-01 header.

Pricing: 1 credit per email that resolves to a person — unmatched emails are free. See Pricing for details. Limits: up to 300 identifiers per submission, and up to 5 active batch jobs per user at a time.

1. Submit your emails

Send your emails in emails — business or personal addresses both work. The response returns a batch_id immediately — the job runs asynchronously.

curl --request POST \
  --url https://api.crustdata.com/batch/person/identify \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'content-type: application/json' \
  --header 'x-api-version: 2025-11-01' \
  --data '{
    "emails": [
      "abhilash@crustdata.com",
      "ankit.harbhajanka@aequs.com"
    ]
  }'

{
    "batch_id": "61f537fc-e93d-4912-8d00-0ece6c7ecf9f",
    "status": "pending",
    "entity": "person",
    "action": "identify",
    "identifier_count": 2,
    "entities_requested": 2,
    "status_url": "/batch/61f537fc-e93d-4912-8d00-0ece6c7ecf9f"
}

You can submit professional_network_profile_urls instead of emails to resolve profile URLs to their crustdata_person_id. Submit exactly one identifier type per job. To be notified when the job finishes instead of polling, include a webhook_url in the request body.

2. Get the results

Poll the status_url (or GET /batch/{batch_id}). While the job runs, status is pending or processing. When it is completed, the response includes a download_url.

curl --request GET \
  --url https://api.crustdata.com/batch/61f537fc-e93d-4912-8d00-0ece6c7ecf9f \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'x-api-version: 2025-11-01'

{
    "batch_id": "61f537fc-e93d-4912-8d00-0ece6c7ecf9f",
    "status": "completed",
    "entity": "person",
    "action": "identify",
    "identifier_count": 2,
    "result_count": 2,
    "entities_requested": 2,
    "entities_fulfilled": 2,
    "created_at": "2026-06-22T03:23:30Z",
    "completed_at": "2026-06-22T03:23:31Z",
    "download_url": "https://crustdata-batch-api-data.s3.amazonaws.com/...&X-Amz-Expires=432000"
}

The download_url points to gzipped JSONL (.jsonl.gz) with one record per submitted identifier. The link is valid for 5 days.

Result format

Each line is one record for an input identifier:

{
  "matched_on": "abhilash@crustdata.com",
  "match_type": "email",
  "matches": [
    {
      "confidence_score": 1.0,
      "person_data": {
        "crustdata_person_id": 1068035,
        "basic_profile": {
          "name": "Abhilash Chowdhary",
          "headline": "Co-founder at Crustdata (YC F24) | Real-time B2B data for AI agents",
          "current_title": "Co-Founder & CEO",
          "summary": "Love building things...",
          "languages": ["English", "Hindi"],
          "last_updated": "2026-06-22T00:11:06Z",
          "location": null
        },
        "updated_at": "2026-06-22T00:11:06Z"
      }
    }
  ]
}

An email with no match returns an empty matches array (and is not billed):

{ "matched_on": "nobody@unknown-domain.com", "match_type": "email", "matches": [] }

Personal emails resolve too

Reverse lookup is not limited to business addresses — a personal email (for example a Gmail address) resolves the same way when it can be matched to a person. Submit it in emails like any other address:

curl --request POST \
  --url https://api.crustdata.com/batch/person/identify \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'content-type: application/json' \
  --header 'x-api-version: 2025-11-01' \
  --data '{
    "emails": ["jane.doe91@gmail.com"]
  }'

The result row has the same shape as above. Personal addresses that cannot be matched return the usual empty matches array and are not billed.

Request parameters

Parameter	Type	Required	Description
`emails`	string[]	One identifier of	Emails to reverse-lookup — business or personal addresses. Max 300 per submission. Result rows carry `match_type: "email"`.
`professional_network_profile_urls`	string[]	One identifier of	Profile URLs to resolve to a `crustdata_person_id`. Max 300 per submission.
`webhook_url`	string	No	URL to call when the job finishes, instead of polling.

Submit exactly one identifier type per job — either emails or professional_network_profile_urls, not both.

Response fields

Field	Description
`matched_on`	The input value this record resolved (the email or profile URL you submitted).
`match_type`	`email` or `professional_network_profile_url` — mirrors the identifier key you submitted.
`matches`	Array of matches. Empty when nothing resolved.
`matches[].confidence_score`	Match confidence, `0`–`1`.
`matches[].person_data`	`crustdata_person_id`, `basic_profile`, and `updated_at` for the matched person.

Job lifecycle

Status	Meaning
`pending`	Job accepted, not yet started.
`processing`	Job is running.
`completed`	Job finished — `download_url` is available.
`failed`	Job failed. Nothing was billed.

Errors

Status	Meaning
`400`	Invalid request — missing identifier, both identifier types, or too many values.
`401`	Invalid or missing API key.
`403`	Permission denied or insufficient credits.
`429`	Too many active batch jobs (max 5 per user).
`500`	Internal server error. Retry with exponential backoff.

API reference summary

Detail	Value
Submit	`POST /batch/person/identify`
Poll	`GET /batch/{batch_id}`
Auth	Bearer token + `x-api-version: 2025-11-01`
Request	One of `emails` or `professional_network_profile_urls` (max 300). Optional: `webhook_url`.
Response	Submit returns `batch_id` + `status`; poll returns `status` and a `download_url` when complete.
Output	Gzipped JSONL, one record per identifier, download link valid 5 days.
Billing	1 credit per matched person; unmatched identifiers are free.
Errors	`400`, `401`, `403`, `429`, `500`

For credit pricing, see Pricing. For throughput guidance, see Rate limits.

What to do next

Need contact data? Use Contact Enrich.
Need full employment history? Use Person Enrich with a profile URL.
Enrich contact info in bulk — Batch Contact Enrich returns emails and phone numbers for a list of profile URLs.
Find people first — use Person Search to build the list to identify.

​How it works

​1. Submit your emails

​2. Get the results

​Result format

​Personal emails resolve too

​Request parameters

​Response fields

​Job lifecycle

​Errors

​API reference summary

​What to do next

How it works

1. Submit your emails

2. Get the results

Result format

Personal emails resolve too

Request parameters

Response fields

Job lifecycle

Errors

API reference summary

What to do next