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Build Prospect List

Deepline’s prospect list pipeline chains 4-5 tasks into one workflow: find companies matching your ICP, enrich with firmographic data, identify decision makers by role, get verified work emails via waterfall enrichment, and validate deliverability. Output is a ready-to-use CSV.
According to industry benchmarks, waterfall enrichment across multiple providers can improve email coverage by 20-40% compared to any single provider (Instantly). Deepline’s waterfall across 44+ providers tries the cheapest provider first and stops at the first valid result, maximizing coverage while minimizing credits.
The pipeline takes an ICP definition and produces a deliverable list of verified contacts — companies matched to your criteria, decision makers identified by role, work emails validated for deliverability.

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How do I build a prospect list with Claude Code?

In Claude Code, type: 
/deepline-gtm Build me a prospect list: B2B SaaS companies in the US with 100-500 employees. Find the VP Sales and VP Marketing at each. Get verified emails.

/deepline-gtm I want 50 qualified leads in the cybersecurity space. Find companies, get decision makers, enrich with emails and phone numbers.
With Codex: 
codex "Build a prospect list: 20 B2B SaaS companies, 100-500 employees, Series A-C. Find VP Sales and VP Marketing with verified emails."

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What does the prospect list building workflow do step by step?

Deepline chains 4-5 tasks into a single pipeline. Each step builds on the previous step’s output, and Claude Code handles the data flow between steps. Single-threaded deals close at ~5%; engaging 5+ stakeholders reaches ~30% (Gong, 1.8M opportunities) — so building lists with multiple contacts per account matters.
1

Find matching companies

Claude Code uses web search or Apollo company-search to find companies matching your ICP criteria.
2

Enrich company profiles

Each company is enriched with enrich_company_finder for revenue, employee count, industry, and funding.
3

Find decision makers

company_to_contact_by_role_waterfall finds contacts matching your target roles at each company.
4

Get verified emails

name_and_company_to_email_waterfall finds work emails for each decision maker via waterfall enrichment.
5

Validate emails

ZeroBounce verification checks deliverability on every found email.
6

Output prospect list

The enriched, validated prospect list is written to prospects.csv.

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Which providers power the prospect list pipeline?

Deepline chains 4-5 specialized tasks, each using waterfall enrichment across multiple providers for higher hit rates. B2B data decays at roughly 22.5% per year (HubSpot via Cognism), which is why the email validation step matters.
  1. Company search — Web search (Claude Code’s native web agent, Exa, or Parallel AI) or Apollo company-search
  2. enrich_company_finder — Company enrichment waterfall
  3. company_to_contact_by_role_waterfall — Decision maker search across Dropleads, Apollo, Icypeas, Prospeo, and Crustdata
  4. name_and_company_to_email_waterfall — Email waterfall across multiple providers
  5. ZeroBounce — Email validation
Each step builds on the previous step’s output. Claude Code wires the data between steps. 
Build a prospect list:
- Find 20 B2B SaaS companies in the US, 100-500 employees, Series A-C
- At each company, find the VP Sales and VP Marketing
- Get verified work emails for each contact
- Write to prospects.csv with: company, domain, revenue, employee_count, contact_name, title, email, email_status
- Start with 3 companies as a pilot, then run the rest if it looks good
This is the most credit-intensive play since it chains multiple paid lookups. Always pilot with 3-5 companies first. A full run of 50 companies with 2 contacts each could use 200-400 credits.
Related: Find Work Email | Find Decision Makers | Qualify & Score Leads

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Frequently Asked Questions

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How do I build a prospect list programmatically?

Use Deepline’s build prospect list play. Type your ICP criteria and target roles in Claude Code: /deepline-gtm Build a prospect list: B2B SaaS, 100-500 employees, find VP Sales and VP Marketing with verified emails. Deepline chains company search, firmographic enrichment, decision maker discovery, email waterfall, and ZeroBounce validation into one automated pipeline.

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Can I build prospect lists in bulk from a CSV?

Yes — two ways. You can start with ICP criteria (Deepline finds companies for you), or pass an existing CSV of company domains and Deepline handles everything from decision maker discovery onward. Either way, output is a single CSV with company data, contact details, and validated emails.

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How much does building a prospect list cost?

This is the most credit-intensive play. Each company uses approximately 1 credit for company enrichment, 1-2 credits per role for contact finding, and 1 credit per email for waterfall + validation. A run of 50 companies with 2 contacts each typically uses 200-400 credits. Always pilot with 3-5 companies first.

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What’s the best way to build a B2B prospect list?

Start with a narrow ICP definition — industry, size range, funding stage, geography. Find matching companies, then use role-based contact discovery for the specific decision makers your sales team talks to. Deepline’s waterfall across 5+ providers (Dropleads, Apollo, Icypeas, Prospeo, Crustdata) produces higher hit rates than any single provider.

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Why build prospect lists inside the IDE?

The entire pipeline — from ICP definition to validated CSV — runs in Claude Code or Codex, the same environment where you write code. Describe the pipeline in plain language and Deepline chains company search, contact discovery, email waterfall, and validation automatically. No column configuration, no manual step wiring, no separate UI. Your pipeline definition lives in the prompt, so it version-controls naturally.