How to Find and Verify Email Addresses (With an Email Lookup API)

An email lookup app takes a person or an address and returns an email plus a deliverability status. This guide does it with a few requests against the LeadOcean API.

You will see the real request, the response shape and the status that decides whether you send.

TL;DR

• You will size a list for free, find one work email, check an address you already hold, and trace an address back to its owner.
• It takes about 15 minutes and spends 6 LeadOcean records. The Free plan has 1,000, one-off, no card.
• Send only to verified and catch_all_valid. Treat every other status as a decision, not a green light.

Prerequisites

• A LeadOcean account. Start free, no card.
• An API key from the app, exported as $LEADOCEAN_API_KEY.
• curl. Optional: the LeadOcean MCP server at https://api.leadocean.io/mcp if you would rather ask in plain English from Claude.
• Optional: the app's Exports page at app.leadocean.io, which covers the bulk case in Step 5.

export LEADOCEAN_API_KEY="your-key-here"

Step 1: Size the list for free

Count before you spend. A count costs no records, so you can tune filters until the number looks right.

Over REST, send count=true and limit=1 as query parameters. The body stays flat JSON, and every filter is an array.

curl -s -X POST "https://api.leadocean.io/v1/people/search?count=true&limit=1" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jobLevel": ["VP"],
    "jobFunction": ["Sales & Business Development"],
    "country": ["CA"],
    "emailStatus": ["verified", "catch_all_valid", "catch_all"]
  }'

Over MCP, the same question is one prompt. The leadocean_count_leads tool is free.

How many VPs of Sales & Business Development in Canada have a mailable email?

Enum values are exact strings. Run leadocean_list_enum_values (or GET /v1/enums/email_status) if a filter returns nothing.

Step 2: Find the people at one company

Search by company domain and a title keyword. Each person returned costs one record, so keep limit small while you test.

curl -s -X POST "https://api.leadocean.io/v1/people/search" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "domain": ["acme.com"],
    "title": ["Head of Sales"],
    "emailStatus": ["verified", "catch_all_valid"],
    "limit": 3
  }'

limit runs from 1 to 100, and you page with meta.nextCursor passed back as cursor. Each row carries meta.source_ids.person_id. Keep it: the next step needs it.

Search rows tell you whether an address exists and its status. They do not return the address itself. That is Step 3.

If you want everyone at the company rather than one title, list its people by domain. It returns the same thin rows, one record per person, and pages to 10,000 rows at most.

curl -s "https://api.leadocean.io/v1/companies/acme.com/people?limit=10" \
  -H "x-api-key: $LEADOCEAN_API_KEY" | jq '.data[] | .meta.source_ids.person_id'

Pick the people you want, then send only their ids to Step 3. You pay for the rows you see, so filter by title before you widen the list.

Step 3: Get the work email

Send the person_id to the work email endpoint. It returns one address, or data: null.

curl -s "https://api.leadocean.io/v2/people/email/work?person_id=1234567890" \
  -H "x-api-key: $LEADOCEAN_API_KEY"

The endpoint only returns addresses at the person's current employer. It also requires the address to be verified, catch_all_valid or catch_all. So data: null means "none that qualify", not "no work email exists".

This call costs one record, including a call that finds nothing. For a personal address, use GET /v2/people/email/personal. It returns a list with no status field, because we do not verify consumer domains.

Step 4: Verify an address you already hold

You do not need the person first. Enrich by email and add reveal_email to see every address and phone we hold, each with its status.

curl -s -X POST "https://api.leadocean.io/v1/people/enrich" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "email": "jane.doe@acme.com", "reveal_email": true }'

Enrich takes exactly one of linkedin_url, email, phone or person_id. A person we hold nothing for returns a 404 and costs nothing.

Gate on the status in the same script, so a person never decides by eye.

curl -s -X POST "https://api.leadocean.io/v1/people/enrich" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "email": "jane.doe@acme.com", "reveal_email": true }' \
  | jq -r '.data.contact_data.contact_emails[]
      | select(.status == "verified" or .status == "catch_all_valid") | .email'

An empty result means no address we hold for that person is safe to send. The enriched status is the one to trust. A search row can read verified while enrichment, which applies the stricter per-address rule, reads untested.

To go the other way, send an address or a phone number and get the owner. Use POST /v2/people/reverse with a JSON body of { "email": "jane.doe@acme.com" }. It costs one record. Our guide to reverse email lookup covers when to use it, and best reverse email lookup tools compares the options.

Step 5: Do it in bulk

For more than a few hundred rows, stop looping over single lookups. Export the filtered list instead.

curl -s -X POST "https://api.leadocean.io/v1/exports" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "ca-vp-sales",
    "filters": { "jobLevel": ["VP"], "country": ["CA"], "emailStatus": ["verified", "catch_all_valid"] },
    "limit": 500,
    "columns": ["person_id", "email_N_address", "email_N_status"],
    "caps": { "emails": 1 }
  }'

An export takes up to 50,000 rows a request and 500,000 a day. Poll GET /v1/exports/{id}, then fetch GET /v1/exports/{id}/download. The app's Exports page does the same with a filter builder, a column picker and the record price shown before you start.

Check the column ids with GET /v1/exports/columns first. Numbered columns are requested as email_N_address and come back as email_1_address, email_1_status, and so on. Each row costs one record, so this request spends up to 500. Bulk CSV export is not on the Free plan; it is included from Solo up.

What you get

The free count from Step 1, run through leadocean_count_leads on 21 October 2026.

Filter: jobLevel VP, jobFunction Sales & Business Development, country CA
Default (verified, catch_all_valid, catch_all):  5,574 people   credits: 0
emailStatus verified only:                       1,854 people   credits: 0

The second number counts people whose best email is verified. It is not a mailable count, because it leaves out confirmed catch-all mailboxes. Search counts of verified are an upper bound, so confirm each address when you enrich it.

Response shape from the API reference for GET /v2/people/email/work, with placeholder values.

{
  "success": true,
  "data": {
    "email": "jane.doe@acme.com",
    "status": "verified",
    "verified_batch_date": "2026-09-20"
  }
}

A date in verified_batch_date means our verifier tested the address. A null means the check was not ours, not that the address is unverified.

Response shape from the API reference for POST /v2/people/reverse, with placeholder values.

{
  "success": true,
  "data": {
    "person_id": "1234567890",
    "full_name": "Jane Doe",
    "job_title": "Head of Sales",
    "company_name": "Acme",
    "company_domain": "acme.com",
    "query": { "email": "jane.doe@acme.com" },
    "matched": { "email": "jane.doe@acme.com", "status": "verified" },
    "matched_in_record": true
  }
}

What each status means

There is no refund or credit-back for bounced emails, so read email_status before you send.

Troubleshooting

FAQ