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Email Waterfall with Validation

Deepline’s cost-aware email waterfall tries deterministic email patterns with free validation first, falls back to 5 paid providers (Dropleads, Hunter, LeadMagic, Deepline Native, PeopleDataLabs) if no pattern matches, and optionally verifies deliverability with ZeroBounce. Pattern matches resolve for 0.1 credits. Waterfall enrichment delivers 20-40% higher email coverage than any single provider (Instantly). You can chain a ZeroBounce validation step after the waterfall to verify deliverability. B2B data decays at roughly 22.5% per year (HubSpot via Cognism), so the verification step catches stale emails that would otherwise bounce.

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How do I find and validate emails with Claude Code?

Tell Claude Code you want verified (not just found) emails. Deepline selects the cost-aware waterfall that tries free patterns first, resolving at 0.1 credits when patterns match, before falling back to paid providers at 0.3 credits each. You can optionally chain ZeroBounce verification.
“Find and validate emails for leads.csv — use the cost-aware approach”
“I want verified emails, not just found emails. Run the full waterfall with validation.”
With Codex: 
codex "Find and validate work emails for leads.csv using cost-aware waterfall"

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What does the email waterfall with validation do step by step?

The cost-aware waterfall runs in three phases: free pattern validation, paid provider fallback, and deliverability verification. Most lookups resolve in Phase 1 at 0.1 credits. The paid fallback only fires when no pattern validates.
1

Try free email patterns

Deepline generates 3 deterministic patterns (first.last@domain, firstlast@domain, first_last@domain) and validates each with LeadMagic’s free validation.
2

Fall through to paid providers if needed

If no pattern validates, the standard waterfall fires: Dropleads, Hunter, LeadMagic, Deepline Native, PeopleDataLabs.
3

Optionally validate deliverability

Chain zerobounce_validate after the waterfall for bounce-risk scoring — checking deliverability, not just syntax.
4

Return verified email with status

The email is returned with a deliverability status: valid, catch-all, or invalid.

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Which providers does the waterfall try and in what order?

The cost_aware_first_name_and_domain_to_email_waterfall runs in three phases, ordered cheapest-first: Phase 1 — Free patterns:
  1. Generate first.last@domain, firstlast@domain, first_last@domain
  2. Validate each with LeadMagic (free validation tier)
  3. If one validates, skip paid providers entirely
Phase 2 — Paid fallback (if no pattern matched): Dropleads, Hunter, LeadMagic, Deepline Native, PeopleDataLabs Phase 3 — Optional deliverability check: Chain zerobounce_validate on the found email for bounce-risk scoring
ScenarioTypical cost
Pattern matches (most common)0.1 credits
First paid provider hits0.3-0.4 credits
Full waterfall + validationUp to 7.2 credits
deepline enrich --input leads.csv --output verified.csv \
  --with '{"alias":"email","tool":"cost_aware_first_name_and_domain_to_email_waterfall","payload":{"first_name":"{{first_name}}","last_name":"{{last_name}}","domain":"{{domain}}"}}'
The cost-aware waterfall saves the most on well-known domains (Google, Stripe, etc.) where email patterns are predictable. For smaller companies with non-standard patterns, it falls through to paid providers.
Related tasks: Find Work Email | Find Personal Email | Build Prospect List

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Frequently Asked Questions

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What is the difference between Find Work Email and Email Waterfall with Validation?

Find Work Email finds an email using a 6-provider waterfall. Email Waterfall with Validation adds two things: free email pattern matching first (0.1 credits when patterns match), and optional ZeroBounce deliverability verification. Use Find Work Email for speed. Use Email Waterfall with Validation when you need deliverability guarantees.

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How much does the email waterfall with validation cost?

Most lookups resolve via free pattern matching at 0.1 credits ($0.008). If patterns fail, the first paid provider typically resolves at 0.3-0.4 credits. Worst case across all providers plus ZeroBounce verification: 7.2 credits. The cost-aware approach saves the most money on well-known domains with predictable email patterns.

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Can I find and validate emails in bulk from a CSV?

Yes. Tell Claude Code “find and validate emails for leads.csv” and Deepline reads your column headers (first_name, last_name, domain), selects the cost-aware waterfall, and enriches every row with a verified email and deliverability status. Always pilot with 3-5 rows first.

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What does the deliverability verification check?

ZeroBounce checks whether the email address is deliverable, not just syntactically valid. It returns: valid (safe to send), catch-all (domain accepts all addresses, delivery uncertain), or invalid (will bounce). This matters for sender reputation in outbound campaigns.

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What data do I need for the email waterfall with validation?

First name, last name, and domain (e.g., “Sarah”, “Chen”, “stripe.com”). The waterfall uses these to generate email patterns before trying paid providers. Company name doesn’t change behavior here — this waterfall is built for the name + domain input combination.