Every cold email tool will happily import a messy CSV and burn your sender reputation in 48 hours. The 10-minute pre-send checklist below is what separates 0.5% reply rates from 5%.
Step 1: dedupe on email
Same prospect on the list twice gets two emails — they're marked spam in 30 seconds. Excel: Data → Remove Duplicates on email column.
Step 2: verify with Kavex
Email Verifier flags bounce/catch-all/role-based emails. Filter to "deliverable" only.
Step 3: split catch-alls separately
Sender tools mark catch-all as deliverable but they often bounce silently. Keep a "catch-all" tier you send to second-week, or skip entirely.
Step 4: split first/last names properly
"John Smith" → first_name=John, last_name=Smith. Most mail-merge fails on "Hi John Smith" — split before send.
Step 5: required columns
email (verified) + first_name + company_name + at least one personalisation field (industry, city, recent post text).
Every number on this page comes from that run, not from a price list.