What Is a Lead List?

A lead list is a set of people or companies you plan to contact, stored with the fields you need to reach them. This page defines the term, walks through how a list is built, and shows how to size one for free.

Key takeaways

• A lead list is a working set, not a database. It is cut from a larger pool of data by filters.
• A good list has a stated audience, one row per person, and an email status you can trust.
• On 2026-10-01, Directors of Marketing in the UK at companies of 51-200 people: 3,556 mailable people.
• LeadOcean counts any filter combination for free, so you can size a list before you pull a single row.

What it is

A lead list is a defined set of people or companies, each with contact details, that a sales or marketing team intends to reach out to.

The word "lead" is loose. In a strict sense a lead has shown interest. In practice most B2B lead lists are cold lists: people who match your target profile and have not heard from you yet.

A list has three parts. An audience rule says who belongs on it. A set of fields says what you know about each row. A purpose says what you will do with it, such as an email sequence, a call block or an ad audience.

A typical row holds the person's name, job title, company name and domain, location, an email with its status, and sometimes a phone number. Richer lists add company size, industry and technology. More fields cost nothing to carry but only help if your message uses them.

Lists also come in two shapes. A people list has one row per person. A company list has one row per account, and you add the people later.

How it works

Most lead lists are built the same way, whatever tool does the work.

1. Define the audience. Write the rule in plain terms: job level, department, country, company size, industry. This is your ideal customer profile turned into filters.
2. Size it. Count how many people match before you pull anything. A rule that returns 40 people is too narrow. One that returns 4 million is too loose.
3. Pull the rows. Fetch the matching people with the fields you need: name, title, company, domain, email, phone.
4. Check the contact data. Read each email's status and keep the sendable ones. Drop duplicates and people already in your CRM.
5. Use it, then refresh it. People change jobs. A list that is a few months old has decayed, so rebuild it from the filter rather than reusing the file.

A worked example

Say your company, Acme (a placeholder), sells a design tool to marketing teams. Your rule is Directors in Advertising & Marketing, based in the UK, at companies with 51-200 employees. You size it twice, on 2026-10-01.

Only about a quarter of the people with an email on file are mailable. Build the list on the first number, not the second.

Both counts are free. The second passes hasEmail, which replaces the default status filter, so it is not a mailable count.

Lead list vs contact list

People use these two terms as if they meant the same thing. They do not.

A lead list often ends up inside a contact list. Once a lead replies, books a call or signs up, they graduate into your CRM.

A lead list is also not an email list. An email list holds addresses only. A lead list holds people, with the company and role context that lets you write a relevant message.

When it matters

Cold outreach

A cold email program lives or dies on list quality. Wrong titles waste sends and bad addresses bounce. A tight audience rule plus a status filter keeps both down.

Sending is also a legal matter. In the US, the FTC says CAN-SPAM "makes no exception for business-to-business email" (FTC CAN-SPAM guide, September 2026). Other countries have different rules. This is not legal advice. Ask a lawyer about the markets you target.

Sizing a market

Counting a list is a cheap way to test an idea. If your ideal buyers number 800 in a country, you know a mass campaign is the wrong play before you build one. A count takes seconds and spends no records.

Account-based work

Sometimes the list starts from companies, not people. You pick 200 target accounts, then pull the buying committee at each one. The list is still a set of people, but the rule is a set of domains.

Feeding an agent or a pipeline

A lead list is also the input to automation. An AI agent or a script takes the rows and enriches, scores or sequences them. Clean fields in means fewer failures downstream.

How LeadOcean handles it

LeadOcean does not store your lead list. It holds the data pool, and your list is a set of filters you keep plus the rows you pull from it. The filters that define the audience are jobLevel, jobFunction, country, employeeRange, industry and emailStatus. There are 50 people filters in all.

Counting is free. Over the REST API, send count=true as a query parameter with limit 1 in the body. The filters go in the JSON body, and meta.total is capped at 100,000.

curl -X POST "https://api.leadocean.io/v1/people/search?count=true" \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jobLevel": ["Director"],
    "jobFunction": ["Advertising & Marketing"],
    "country": ["GB"],
    "employeeRange": ["51-200"],
    "emailStatus": ["verified", "catch_all_valid", "catch_all"],
    "limit": 1
  }'

The response returns an empty data array and meta.countOnly set to true. Drop count=true and raise limit to pull rows, up to 100 per page. Each person returned counts one record.

To move a whole list into a spreadsheet, use POST /v1/exports. The app at app.leadocean.io has an Exports page with a filter builder, a column picker, the record price before you start, and a CSV download. Email columns arrive as email_1_address and email_1_status.

From an AI client, the MCP tool count_leads does the same sizing for free, and export_leads pulls the rows. The Free plan gives you 1,000 records, one-off, no card. Pro is $499 a month, flat. See pricing.

The dataset is refreshed monthly, and each record carries its own fetched_at date. To go deeper, see the use-case hub for list building, the comparison of lead list building tools, the Lead List Builder skill, and a step-by-step build in Windsurf.

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