How to Generate B2B Leads (From an ICP to a Mailable List)

You generate B2B leads by turning your ideal customer profile into filters, sizing the list before you spend anything, and pulling only the people who match. This guide does that with one filter set against the LeadOcean API.

TL;DR

• Write the ICP as a flat JSON filter set, then check the size with a free count before you pull a single row.
• Takes about 20 minutes. The sample spends 25 records. The full list spends one record per row.
• On the Free plan you have 1,000 records for life, so a 2,090-row list needs Solo ($97 a month) for bulk CSV export.

Prerequisites

• A LeadOcean account. The free plan gives you 1,000 records, no card.
• An API key in your shell: export LEADOCEAN_API_KEY=...
• curl and jq.
• Optional: the LeadOcean MCP server at https://api.leadocean.io/mcp if you want to run steps 1 and 2 from Claude or ChatGPT.

Step 1: Write the ICP as filters

An ICP is a filter set, not a paragraph. Turn each sentence of your ICP into one field and keep it flat.

Example ICP: "VPs of sales at US software companies with 51 to 200 employees." In LeadOcean that is:

{
  "jobLevel": ["VP"],
  "jobFunction": ["Sales & Business Development"],
  "industry": ["Software Development"],
  "employeeRange": ["51-200"],
  "hqCountry": ["US"],
  "emailStatus": ["verified", "catch_all_valid", "catch_all"]
}

Two rules keep this honest. Every filter is an array of strings, and enum values are exact strings, so "VP" works and "vp" does not. The emailStatus line makes the list mailable. Drop it and you are counting people you cannot email.

Step 2: Resolve enum values before you guess

Industry has 534 values and country has 254. Guessing returns empty results. List the exact strings first.

From an MCP client, ask:

Use leadocean_list_enum_values for name=industry, q="software".
Then do the same for job_function and employee_range.

The tool is free and spends no records. It returns the exact labels, such as Software Development and Sales & Business Development. Copy them into your filter set unchanged.

Step 3: Size the list for free

Check the size before you pull anything. A people search with count=true and limit=1 costs nothing. Note that count=true goes in the query string, not the JSON body.

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"],
    "industry": ["Software Development"],
    "employeeRange": ["51-200"],
    "hqCountry": ["US"],
    "emailStatus": ["verified", "catch_all_valid", "catch_all"]
  }' | jq '.meta | {total, totalIsExact, distinctCompanies}'

meta.total is capped at 100,000, so a broad ICP shows a floor. If the number is too big, add a filter. If it is under 100, loosen one. Aim for a list you can actually work.

You can run the same count from MCP with leadocean_count_leads. For company-level sizing, GET /v1/companies/count and leadocean_count_companies are free as well.

Step 4: Pull a sample, then export

Pull 25 rows first and read them. If the titles look wrong, fix the filters now, not after you have spent the whole list.

curl -s -X POST "https://api.leadocean.io/v1/people/search" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jobLevel": ["VP"],
    "jobFunction": ["Sales & Business Development"],
    "industry": ["Software Development"],
    "employeeRange": ["51-200"],
    "hqCountry": ["US"],
    "emailStatus": ["verified", "catch_all_valid", "catch_all"],
    "limit": 25
  }' | jq '.meta, .data[0]'

Search returns a thin projection with no contact points. Page with meta.nextCursor. One search pages to 10,000 rows, then meta.depthCapped turns true and no cursor is issued. Narrow the filters instead of walking further.

When the sample looks right, export the whole list. Exports take up to 50,000 rows a request and 500,000 a day. Bulk CSV export is not on Free.

curl -s -X POST "https://api.leadocean.io/v1/exports" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "vp-sales-us-software-51-200",
    "limit": 2090,
    "filters": {
      "jobLevel": ["VP"],
      "jobFunction": ["Sales & Business Development"],
      "industry": ["Software Development"],
      "employeeRange": ["51-200"],
      "hqCountry": ["US"],
      "emailStatus": ["verified", "catch_all_valid", "catch_all"]
    }
  }'

Prefer a UI? The Exports page in the app has the same filter builder, a column picker, the record price before you start and a CSV download.

What you get

The free count for this ICP, run with leadocean_count_leads on 2026-10-21. We passed the first five filters. The tool's default email filter (verified, catch_all_valid or catch_all) stands in for the emailStatus line.

{
  "total": 2090,
  "totalIsExact": true,
  "totalAll": 5685,
  "distinctCompanies": 1204,
  "credits": 0
}

Read it like this. 2,090 people match and have an email worth sending to (verified, catch_all_valid or catch_all). Without the email condition the same filters match 5,685 people. They sit at 1,204 distinct companies, so about 1.7 buyers per account. The call cost 0 records.

A search row, response shape from the API reference, placeholder values:

{
  "success": true,
  "data": [
    {
      "profile_data": { "full_name": "Jane Doe", "headline": "VP Sales at Acme" },
      "contact_data": {},
      "resume_data": {},
      "meta": {}
    }
  ],
  "meta": { "count": 1, "limit": 25, "credits": 1, "nextCursor": "..." }
}

Troubleshooting

FAQ