Deduplication guide

Deduplicate your contacts before you import to HubSpot

The cheapest place to catch a duplicate is before it becomes two records. Here is how to find duplicate contacts across your lists and clean the file before it ever reaches HubSpot.

If you are about to import a list into HubSpot and want to catch the duplicates before they become two records, this guide is for you. If what you need is to bulk-merge tens of thousands of records already sitting in HubSpot, that is a job for an in-CRM merge tool. Datuma cleans the file before it goes in, and writes verified fields back afterwards, but it does not merge records inside HubSpot.

Why duplicates get into HubSpot in the first place

HubSpot matches incoming contacts on email address. That catches an exact repeat, but it walks past the ways the same person actually shows up twice. A different spelling of a name. A personal email on one list and a work email on another. The same person at a new organisation with a new address. Import two lists a month apart and none of those are caught, so they land as separate records.

Once they are in, the cost climbs. Two reps work the same person. A sequence emails them twice. Your reporting counts one deal as two. Cleaning it up afterwards means finding each pair by hand and merging without losing the history, which is exactly the job nobody volunteers for.

How to find and remove duplicates before you import

Step 1: Assemble every list into one file

Pull the lists you are about to import, plus a recent export of your existing HubSpot contacts, into a single spreadsheet. Duplicates hide in the gaps between lists, so scanning them together is what surfaces them.

Step 2: Scan the whole file, not just exact emails

Run a full pairwise scan that matches on more than an identical email. Different spellings, casing, whitespace, and a person at a new organisation should all be caught, each with a confidence score so you can trust the clear matches and review the close calls.

Step 3: Review the pairs and decide

Look at each suggested duplicate with the evidence beside it and decide whether to keep one record or both. Nothing should be merged for you without your say-so.

Step 4: Import only the survivors

Import the cleaned file, so HubSpot never receives the duplicate in the first place. Two records for one person is a problem you avoid rather than one you fix later.

Find duplicate contacts across two lists, free

Datuma runs a full cross-list scan at £0.00, at any size. Every new list is checked against itself and against every list you have ever uploaded, so the same person in two places is caught before you import, before you enrich, and before a rep calls them twice.

Because deduplication runs before enrichment, you never pay to enrich a record you already have. You only pay for fresh enrichment on the contacts you keep, at about £0.10 each, priced in pounds.

Merge in place, or clean before import

These are two different jobs. If your records are already in HubSpot and you need to merge thousands of them in place, dedicated in-CRM merge tools such as Insycle and Dedupely do that work inside HubSpot itself.

Datuma works one step earlier and one step to the side. It cleans the file before you import, so the duplicate is never created, and it scores every contact from 0 to 100 so you know which of the survivors is worth acting on. After import it writes verified fields back into HubSpot one way, into its own Datuma fields, without overwriting or creating records. Clean and score before, verify after, rather than merge in place.

What Datuma writes back to HubSpot

Once contacts are in HubSpot, Datuma writes verified, scored data back into its own Datuma fields beside your data. A Trust Score from 0 to 100, a Verified Readiness tier, and the verified current title and organisation, added to the records you already have. It is one way and additive. It never overwrites your fields, never creates records, and never merges records inside HubSpot.

See how the CRM sync works, or read how Datuma finds every duplicate.

Deduplicating before HubSpot import, common questions

Does HubSpot remove duplicate contacts automatically?
HubSpot has a duplicate management tool, but it works on records already inside HubSpot and matches on a limited set of fields. It does not scan a spreadsheet before you import it, and it will not catch the same person spelled differently across two lists. Catching duplicates before the import is what stops two records for one person being created in the first place.
How do I find duplicates across two lists before importing to HubSpot?
Combine the lists into one file and run a full scan across the whole file, not just an exact email match. Datuma checks each new list against itself and against every list you have ever uploaded, so a person who appears in both, or in a new list and an earlier export, is surfaced with the matching evidence and a confidence score. You review the pairs and import only the records you want to keep.
Will Datuma merge duplicate records inside HubSpot?
No. Datuma cleans the file before it reaches HubSpot and, once contacts are in, writes verified fields back into their own Datuma fields, one way, without overwriting or creating records. It does not merge records inside HubSpot. If you need to merge records already sitting in HubSpot, use a dedicated in-CRM merge tool for that job.
How much does it cost to deduplicate a list before import?
The full duplicate scan is £0.00 at any size, and it runs before you pay to enrich anything. You only pay if you go on to enrich the contacts you keep, at about £0.10 per enriched contact, priced in pounds.

Find your duplicates free, before you import

Upload your lists and see every duplicate pair with a confidence score. The scan is free. Your team decides what to keep, and only the survivors go into HubSpot.

Start free How deduplication works

HubSpot is a registered trademark of HubSpot, Inc. Insycle and Dedupely are the trademarks of their respective owners. Datuma is independent and is not affiliated with, endorsed by, or sponsored by HubSpot, Insycle or Dedupely.