> For the complete documentation index, see [llms.txt](https://docs.mediarithmics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mediarithmics.io/setup-and-monitor/collect-and-manage-your-data/import-data-in-batch/data-loader/load-identifiers.md).

# Load identifiers

Associate several identifiers from a CSV file with a single user.

## Your goal

Declare, from a CSV file, that several identifiers on the same row belong to the same person - so their UserPoints become one.

## Expected outcome

One user per row, carrying all the identifiers on that row.

{% hint style="danger" %}
This operation merges UserPoints, and a merge cannot be undone. Check the file before uploading: a row that wrongly pairs two people permanently joins their histories.
{% endhint %}

## Prerequisites

* A CSV file meeting the [file requirements](/setup-and-monitor/collect-and-manage-your-data/import-data-in-batch/data-loader.md#file-requirements), with **at least two identifier columns**.
* The compartments and registries the identifiers belong to.

## Configure the import

You must configure **at least two properties** from the CSV that you want to bind together. For each of them:

* Select the **CSV property** to use as the identifier.
* Choose the **identifier type**: `USER_ACCOUNT`, `USER_EMAIL`, or `USER_DEVICE_TECHNICAL_ID` - and specify the related **compartment** for an account, or **registry** for a device technical ID.
* Optionally select a **hashing** method. Hashing is the only transformation available on identifiers, and only one method per field.

## What happens per row

Every identifier provided is used to match an existing user:

| Situation                                | Result                                                               |
| ---------------------------------------- | -------------------------------------------------------------------- |
| A user is found with a single identifier | The other identifiers are attached to that user.                     |
| Several users are found                  | They **merge** into a single user with all the identifiers attached. |
| No user is found                         | A **new** user is created, with all the identifiers attached.        |

## Example file

```csv
Email_sha256,Email_md5,user_account,aaid
ce5bfa8406dd062b059a4b841bf36de186977fe515dc5a704a58e973cab1a5d5,0859e624f8a3eae16afd07a516d21259,X1234,a5ac7016-f329-4ef9-9208-1263aaf12dae
9980f7e8331dce3bfa2e3b3ab6b69dcb960658bcb400801cece7873afeb5a905,be61735432bd1fb5a84de127e3423e35,Y12,dec1c0b2-d7ed-4c21-8b01-3cad93a919c5
```

Four identifier columns on one row: two email hashes with different functions, an account ID, and a mobile advertising ID. Each is mapped to its type, and the row declares that all four are the same person.

{% hint style="info" %}
Two hashes of the same address are two distinct identifiers in the platform, so declaring both is meaningful when your partners use different functions.
{% endhint %}

## Verify

* The transformation report shows no errors before upload.
* The execution succeeds with the expected success count.
* A test user that had several UserPoints now has one, carrying all the identifiers.
* The UserPoint total does not fall much further than the number of merges you expected. See [Monitor collection volume](/setup-and-monitor/operate-and-monitor/monitor-collection-volume.md).
* No ordinary user becomes a [hyper point](/setup-and-monitor/collect-and-manage-your-data/design-your-data-model-and-schema/user-identity/userpoint-and-identity-graph.md#hyper-point).

## Related pages

<table data-view="cards" data-search="false"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Enrich users with identifiers</strong></td><td>The same job through the API.</td><td><a href="/setup-and-monitor/collect-and-manage-your-data/import-data-in-batch/enrich-users-with-identifiers.md">Enrich users with identifiers</a></td></tr><tr><td><strong>Resolve identities</strong></td><td>The strategy behind these declarations.</td><td><a href="/setup-and-monitor/collect-and-manage-your-data/design-your-data-model-and-schema/user-identity/resolve-identities.md">Resolve identities</a></td></tr><tr><td><strong>Data loader</strong></td><td>The upload flow and file requirements.</td><td><a href="/setup-and-monitor/collect-and-manage-your-data/import-data-in-batch/data-loader.md">Data loader</a></td></tr></tbody></table>


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