When lemlist finds hundreds of duplicate contacts or companies, merging them one by one takes hours. Bulk merge lets you merge many duplicate groups in one go: you pick one rule, and in each group lemlist keeps one record according to that rule and merges the others into it.
Limitations
Bulk merge is in beta.
A merge cannot be undone. Once confirmed, a bulk merge cannot be stopped, and deleted records cannot be restored.
A merge combines 10 records at most. A group with more than 10 records fails.
Select all has no limit. When you tick groups one by one, you can select up to 1,000 groups per bulk merge.
Groups already being merged cannot be selected again until their merge is finished.
Your CRM does not mirror the merges you make in lemlist.
Before you start
Duplicate groups are listed in Settings > Data management > Duplicates, in the Contacts and Companies tabs.
If your workspace is connected to a CRM, clean duplicates in your CRM first. lemlist mirrors the merges you make in your CRM, but your CRM does not mirror the merges you make in lemlist.
Review the groups you select, especially companies grouped by Website or Similar names: subsidiaries and brands of one group can legitimately share a domain or a name.
How to bulk merge duplicates
Go to Settings > Data management > Duplicates and open the Contacts or Companies tab.
Tick the groups you want to merge, or click Select all. Use Search duplicates… or the All duplicates filter first to narrow Select all to the groups you trust.
Click Merge in the selection bar at the bottom of the screen.
Under Keep contact (or Keep company), choose which record to keep in each group.
Click Continue, check the number of merges, tick the confirmation and click Merge.
✅ Verify: each selected group shows Merging… in the list.
The merge runs in the background. You can keep working or leave the page.
Choose which record to keep
One rule applies to every selected group. When two records are equal on that rule, the next criterion decides.
Rule | Record kept in each group | On a tie |
Synced with CRM | The record linked to your CRM and still syncing. Only available when a CRM is connected. | Most recent engagement, then most recently updated |
Most recent engagement | The record you contacted most recently. A record never contacted comes last. | Most recently updated |
Most recently updated record by lemlist | The record edited most recently in lemlist. A record never edited counts with its creation date. | Order of the group |
Most recently created | The newest record | Order of the group |
Oldest created | The oldest record | Order of the group |
💡 Connected to a CRM? Choose Synced with CRM. The record you keep is the one that still syncs with your CRM, so your CRM keeps receiving its updates.
What happens in each group
One record is kept. The others are merged into it, then deleted.
Its values are preserved. Its empty fields are filled with the values of the other records, taken in the order of the chosen rule. When both records have a value, the kept record's value wins and the other one is not kept. Custom fields work the same way.
Everything else moves to the kept record:
For contacts: campaigns, activities, tasks, lists and signal agents. If two merged contacts were in the same campaign, the kept contact stays in it once, with the most advanced progress. If any merged contact was marked Do not contact, the kept contact is too. The kept contact keeps its own email addresses, and only takes another contact's address when it has none.
For companies: contacts, activities, tasks, lists and signal agents.
In your CRM: the CRM record linked to the kept record is updated with the kept values, like any edit in lemlist. If the kept record was not linked to your CRM, it takes the link of another record of the group. The CRM records of the deleted duplicates are not merged or deleted in your CRM: they stay there, no longer synced with lemlist.
Each merge appears in the Activities tab of the kept record and in your team activity log.
💡 Want to choose values field by field for a group? Click the Merge button on that group instead. The merge window lets you pick, for each field, which value to keep.
Follow the progress
Each selected group shows its status in the list:
Merging…: the group is waiting for its turn or being merged.
Merged: the group was merged.
Skipped: the group was no longer a duplicate when its turn came. For example, it was dismissed, one of its records was deleted, or its records were already merged through another group.
Failed: the group could not be merged. Hover the badge to see why. You can select a failed group again and retry.
While you stay on the Duplicates screen, a message shows how many groups are being merged, then a summary: merged, skipped and failed.
Why a group can fail
The group has more than 10 records. A merge combines 10 records at most.
A record is being enriched. Retry once the enrichment is done.
A record was deleted before the group's turn.
You chose Synced with CRM and your CRM was disconnected before the group's turn. Reconnect your CRM and retry. lemlist never switches to another rule on its own.
Good to know
One record in two groups. The same record can belong to two groups, for example same email and same LinkedIn URL. The first group to be merged absorbs it; the second group is then merged with the records left, or skipped.
Who can bulk merge? Every member of the workspace who can open the Duplicates screen.
If your case is different
If you want to avoid creating duplicates when you import leads, see How to prevent duplicate leads when importing.
If you want to clean duplicate companies through the API to unblock CRM sync, see How to automate duplicate company cleanup and unblock CRM sync.
If you want to filter, edit or bulk-manage contacts, see Use the Contacts section.