Clean a HubSpot contact list before you import it
HubSpot import failures are rarely dramatic: rows get skipped, contacts merge unexpectedly, or the same person appears twice because one export wrote the email in capital letters and the other did not.
Ten minutes of preparation prevents weeks of dirty CRM data — and the cleanup runs entirely in your browser, which matters when the file contains customer records.
Check your file before you import it
Free preflight and fixes in your browser. Nothing is uploaded.
The four problems that cause rejected or merged rows
Check for these before importing:
- Invalid emails: missing domain, double @, trailing spaces. HubSpot rejects the row and continues without telling you loudly.
- Duplicate emails: the same contact twice in one file, or differing only by case, produces unexpected merges.
- Inconsistent blanks: "", "N/A", "null" and "-" all mean empty to a human and different values to an importer.
- Phone numbers: any format is accepted, but inconsistent formats (spaces, local prefixes) make the data unusable for automation later.
Prepare the list in one pass
BeforeImport has a dedicated HubSpot check: it requires a valid, unique email column, flags every invalid and duplicate address with row numbers, trims invisible characters, lowercases emails and can normalize phone numbers to the international E.164 format used by CRMs and dialers.
Nothing is written until you approve it: the diff preview shows exactly which cells change.
A privacy-safe workflow for customer data
Generic CSV cleaners upload your file to a server. For a CRM list that is a data-processing decision with legal weight. BeforeImport never uploads: parsing, cleaning and export happen on your device, so the list stays under your control and nothing needs to be disclosed to a processor.
Frequently asked questions
Why did HubSpot skip some rows in my import?
Almost always an invalid or empty email — it is the required unique field for contacts. The preflight lists the exact rows before you import, so nothing is skipped silently.
Does HubSpot treat EMAIL and email@ as duplicates?
Email comparison is case-insensitive in HubSpot, but your file can still contain two rows that differ in other fields. Deduplicating on the email key before import avoids surprise merges.
Should I convert phone numbers before importing?
If anyone will call or automate messages from the CRM, yes: E.164 (+393331234567) is the format that survives integrations. It is optional in the free plan and included in PRO.
Is it safe to clean customer data with an online tool?
Only if the data never leaves your device. BeforeImport runs entirely in the browser: there is no upload and no server that could store the list.
Related guides
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