# Merge rules — Dedupely Knowledge Base

> This guide explains how Dedupely merges CRM records using native logic and how to customize merge rules to control which values are kept or discarded.

- URL: https://dedupe.ly/knowledge-base/merge-rules
- Section: knowledge-base
- Site index: https://dedupe.ly/llms.txt
- Any page: append `.md` to its URL for this plain-text form

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## Merge rules

Dedupely makes merging CRM records simple, powerful, and accurate. Our merging tools follow your CRM’s native logic while also giving you the option to fully customize how fields are handled, so you always stay in control of your data.

### Default merge behavior

Out of the box, Dedupely merges duplicate records using your CRM’s **internal core merging functionality**. This means:
- Merges are executed **within your CRM,**we don’t override or bypass your platform’s built-in rules.
- If you’re already familiar with merging records directly in your CRM, Dedupely follows **the exact same logic**, because the merges happen using your CRM’s own tools.
-
**However**, even though we respect your CRM’s built-in merging rules, Dedupely allows you to choose which values should be
**kept (win)** or
**discarded (lose)** during a merge,
*as long as the fields are not read-only* in your CRM.
- The **most recent** field values are typically retained.
- The **oldest Record ID** is preserved.
- All **associations and activities** (emails, calls, notes, etc.) are kept intact.
- **Blank fields will never overwrite** existing data.
You don’t need to set up any rules to start merging, but you can take it further with **custom merge rules** if you want full control.
Helpful tip: Each CRM handles merging a little differently. For a deeper understanding of how merging works within your CRM, check out the following resources:
-
[HubSpot CRM: Merge Records in HubSpot](https://knowledge.hubspot.com/records/merge-records)
-
[Pipedrive: Merge Duplicates in Pipedrive](https://support.pipedrive.com/en/article/merge-duplicates)
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[Salesforce: Guidelines for Merging Duplicate Accounts](https://help.salesforce.com/s/articleView?id=sales.account_merge.htm&type=5)

### Associations and activities are preserved

When you merge records in Dedupely, all activities (such as notes, calls, tasks) and associations (linked companies, deals, contacts) are preserved. Dedupely does not delete any data; it only consolidates it. You can merge with confidence knowing your CRM history is safe.

### Using custom merge rules

If you want more precision over which field values “win” during the merge, Dedupely’s **Merge Rules Engine** gives you that control.
Custom merge rules allow you to:
- Set which values should **win or lose** for specific fields.
- Apply rules to one or multiple **Duplicate Searches** (deduplication scans).
- Filter based on conditions like oldest or newest record, source, or other fields.

### How to set a merge rule

Here’s how to build your own rule using our merge engine:
- **Record type:**Select the object: Contacts, Companies, or Deals.
- **Affected field:**Choose the field the rule applies to (e.g., First Name).
- **Win/lose:**Choose whether this field should be preserved (Win) or discarded (Lose).
- **Filter by field:**Add an IF condition that defines the rule’s trigger (e.g., Create Date).
- **Operator:**Select the comparison logic (e.g., Is Oldest, Is Newest).
- **Duplicate search:**Choose whether the rule applies to a specific Duplicate Search or all.

### Example rule scenario

**Objective**: Make sure the
*first name* from the
**oldest contact** is
*not* kept.
- **Record type**: Contacts
- **Affected field**: First Name
- **Win/lose**: Lose
- **Filter by field**: Create Date
- **Operator**: Is Oldest
- **Duplicate search**: Any
This rule ensures that when merging contact records, the first name from the oldest record will lose. The winning name will be chosen from newer records instead.
You can stack multiple rules to handle various scenarios across different fields.

### Visualizing merge rules in action

Once your rules are created and saved, go to your **Duplicate Searches** to see how they affect your matches.
- In each duplicate group, field values that will win (as determined by your rule) will appear in **bold and italicized** text.
- This visual cue confirms that your rule is actively controlling the outcome of the merge.
- You can always edit or remove rules if needed.

### Important note on data privacy

All sample records shown in the interface are generated using fake or dummy data. No real personal or customer data is ever exposed in examples or demonstrations.

### Still stuck?

-
Need help?
[Talk to support](https://dedupe.ly/contact)
-
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[Book a Zoom with sales](https://meetings.dedupe.ly/meetings/hampus-isaksson/dedupely-zoom-schedule)
-
Reading this with a model?
[Read this page as Markdown](https://dedupe.ly/knowledge-base/merge-rules.md)
-
Feeding it the whole site?
[Read llms.txt](https://dedupe.ly/llms.txt)

### Get started for free

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