ReadyCSV guides
HubSpot CSV formatting and import error guides
Short, practical explanations of common HubSpot CSV import failures and how to format a contacts CSV locally before importing.
Start with the checklist or the error you are seeing
How to format a CSV for HubSpot import
Use an end-to-end HubSpot contact CSV checklist before uploading: identity, headers, emails, dates, phones, owners, encoding, and enums.
HubSpot import date format errors
Fix HubSpot date columns that use Excel serials, written-out dates, dots, or unsupported formats.
HubSpot invalid email import error
Understand INVALID_EMAIL, INVALID_DOMAIN, duplicate emails, and additional email address imports.
HubSpot lifecycle stage import error
Check lifecycle stage and lead status values before HubSpot rejects an import row.
HubSpot import missing required fields
Fix contact rows missing First name, Last name, and Email before a HubSpot import.
HubSpot contact owner import error
Review Contact owner values that need an active HubSpot user email or internal owner value.
HubSpot CSV column format errors
Fix duplicate headers, blank headers, and rows with extra cells before importing a CSV.
HubSpot phone number format import
Review HubSpot phone number format import risks and use E.164-style values before uploading contacts.
HubSpot import special characters broken / UTF-8 encoding CSV
Fix CSV encoding workflows when HubSpot import special characters look broken, such as José instead of José.
HubSpot import duplicate contacts / duplicate email
Review duplicate emails, duplicate rows, and blank-email dedupe risk before importing HubSpot contacts.
HubSpot import unmapped / unrecognized columns
Review unmapped CSV headers, manual mapping risks, and local mapping suggestions before HubSpot import.
HubSpot website URL import format
Clean Website URL values, whitespace, and clearly invalid website text before importing contacts.
Preflight locally before upload
ReadyCSV checks HubSpot contact CSVs in your browser before you upload them to HubSpot. Your CSV contents stay on your device: no upload, no account, no AI calls.
Use the guides to understand the import risk, then run a local preflight and review the findings before importing. ReadyCSV does not guarantee import success.
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