✓ TestedWorks with CSV, Excel, Google Sheets → JSON-LD Schema
By dataclean.to team · 2026-02-12
HubSpot CRM accumulates contact email addresses from form submissions, imported lists, sales prospecting, integrations, and manual entry by your team. Despite HubSpot's built-in email health tools, exports still contain addresses that are formatted incorrectly, no longer active, or duplicated across contact records. dataclean.to processes your HubSpot contact export to perform thorough email validation, fix domain typos, and deduplicate entries that HubSpot's merge tool missed.
The Problem
HubSpot's strength as a central contact repository is also its weakness for email quality. Contacts flow in from multiple channels without consistent validation: form submissions may have email fields without format checking, imported CSV lists bypass all validation, and sales reps manually add prospect addresses from business cards and LinkedIn. HubSpot marks contacts as 'hard bounced' after a failed send, but contacts who were never emailed have unknown deliverability status. The CRM stores alternate email addresses in secondary properties that may be more current than the primary email. Lifecycle stage changes and deal associations do not trigger re-validation, so a contact promoted to 'customer' may still have the typo-laden email they submitted on a form months earlier. Contact imports from other CRMs can introduce encoding issues where accented characters in email local parts get corrupted. HubSpot contact export documentation
How to Fix It
1
Export contacts from HubSpot
Go to Contacts in HubSpot, apply filters if needed (by list, lifecycle stage, or last activity date), and export as CSV. Include primary email, secondary email, bounce status, and any custom email properties.
2
Upload the HubSpot export to dataclean.to
Import your contact CSV. The platform processes all email columns, validating primary and secondary addresses independently while checking for issues specific to CRM exports like encoding errors.
3
Validate unverified contacts
Focus on contacts that HubSpot has never emailed and therefore never bounce-checked. These unknown-status addresses are validated for syntax, domain health, and disposable provider detection.
4
Reconcile primary and secondary emails
Compare primary and secondary email addresses for each contact. When the primary is invalid but the secondary passes validation, flag it for a swap in HubSpot. Remove secondary addresses that are duplicates of the primary.
5
Export and update HubSpot contacts
Download the validated contact data. Use HubSpot's import tool to update existing contacts with corrected email addresses. Exclude hard-bounce contacts from future imports to keep your database clean.
Frequently Asked Questions
Does HubSpot already validate emails?
HubSpot validates email format on its own forms but does not check domain deliverability. Imported contacts and manually added records bypass even format validation. HubSpot only marks an address as bounced after an actual failed send, which means unsent contacts are never checked.
How do I handle contacts HubSpot marked as hard bounced?
HubSpot's bounce flag is reliable for addresses that failed delivery. dataclean.to can re-verify these addresses because some bounces are temporary (full mailbox, server outage) rather than permanent. However, most hard bounces indicate genuinely invalid addresses.
Can I clean a specific HubSpot list without exporting all contacts?
Yes. In HubSpot, navigate to the specific list you want to clean, export just that list as CSV, and upload it to dataclean.to. This is more efficient than exporting your entire contact database.
Example: Input → Output
name
email
phone
city
status
Alice Johnson
alice@example.com
+1-555-0101
New York
active
alice johnson
ALICE@EXAMPLE.COM
5550101
new york
Active
Red rows show common data quality issues. dataclean.to normalizes and generates JSON-LD automatically.