# Duplicate Detection

Source: https://neondeerdata.com/docs/platform/duplicate-detection/

Duplicate Detection finds People and Companies in your Attio workspace that look like the same person or company, shows the evidence behind every match, and merges records only after someone with permission approves the merge.

## How it works

The app has two parts.

| Part         | Runs                                                                                                                                                 | Does                                                                                                                  |
| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- |
| Attio app    | Inside your Attio workspace                                                                                                                          | Checks new and updated records and reports matches to Neon Deer. It does not merge records or write to Attio lists.   |
| Platform app | On the [Neon Deer Platform](https://neondeerdata.com/docs/platform/), at [app.neondeerdata.com/duplicates](https://app.neondeerdata.com/duplicates/) | Holds your matching rules, runs scans of your whole workspace, and is where you review duplicates and approve merges. |

Work moves through four stages, and only the last one changes anything in Attio.

1. **Configure rules.** Rules decide which records are compared and what counts as a potential duplicate.
2. **Scan.** A scan reads your records and groups likely duplicates into sets. Scans only read data; they never merge or edit records.
3. **Review.** Each set shows the evidence for and against a match. Depending on your plan, an `AI score` can help you judge the evidence. Sets are sorted into `Not reviewed`, `Ready to merge` and `Needs attention`.
4. **Approve merges.** A merge runs only when someone with permission explicitly approves it. Whether merging is included depends on your plan; see [Settings → Billing in Neon Deer](https://app.neondeerdata.com/).

## Getting started

1. **Install the Attio app.** Install Duplicate Detection into your Attio workspace from the [Attio Marketplace](https://attio.com/apps/check-for-duplicates).
2. **Connect to Neon Deer.** Open [Duplicate Detection on Neon Deer](https://app.neondeerdata.com/duplicates/) and sign up or sign in. Setup has two steps. `Workspace access` lets Neon Deer read your records and perform the merges you approve; a workspace admin connects it with `Connect Attio`. `Automatic detection` receives record changes from Attio so new and updated records can be checked automatically; `Finish setup in Attio` completes it in the [Attio app](https://app.attio.com/%5F/settings/apps/installed/check-for-duplicates/).
3. **Check your rules.** Every built-in rule starts switched on. Review them, and add your own if you need to, on the `Duplicate detection rules` page. See [Matching rules](https://neondeerdata.com/docs/platform/duplicate-detection/matching-rules/).
4. **Run your first scan.** On the `Duplicates` page, choose `Start your first scan`. A scan checks the records that already exist in your workspace.
5. **Review the sets.** Start with the sets marked `Not reviewed`. See [Reviewing duplicates](https://neondeerdata.com/docs/platform/duplicate-detection/reviewing-duplicates/).
6. **Approve merges.** Approve only the merges you are sure about: merges cannot be undone in Attio. See [Merging records](https://neondeerdata.com/docs/platform/duplicate-detection/merging-records/).

Once [Automatic detection](https://app.neondeerdata.com/duplicates/settings) is set up, the Attio app checks records as they are created or updated and reports what it finds to Neon Deer. Like scans, it never merges.

## In these docs

- [Matching rules](https://neondeerdata.com/docs/platform/duplicate-detection/matching-rules/): the built-in rules for each object, exact and similar matching, custom rules, and how sets form.
- [Scans and schedules](https://neondeerdata.com/docs/platform/duplicate-detection/scans-and-schedules/): running a full scan, following its progress, reading the results, and scheduling scans.
- [Reviewing duplicates](https://neondeerdata.com/docs/platform/duplicate-detection/reviewing-duplicates/): the evidence panel, the record that stays, Not duplicate decisions, and AI scores.
- [Merging records](https://neondeerdata.com/docs/platform/duplicate-detection/merging-records/): building and approving a merge, the safeguards before anything runs, and backups.

For how Neon Deer handles the record data it reads, see the [Privacy Policy](https://neondeerdata.com/privacy/) and our [sub-processors](https://neondeerdata.com/sub-processors/).

## Older versions of the Attio app

Older versions of the Attio app found duplicates inside Attio and added them to Attio lists. They are described in the [legacy version documentation](https://neondeerdata.com/docs/integrations/duplicate-detection-for-attio/). The current app keeps those lists but no longer updates them.