---
title: Resource mapping
description: A synchronization mapping specifies a relationship between objects and their attributes in two data stores. The following example shows a typical attribute mapping, between objects in an external LDAP directory and an IDM managed user data store:
component: pingidm
version: 7.2
page_id: pingidm:synchronization-guide:mappings
canonical_url: https://docs.pingidentity.com/pingidm/8.1/synchronization-guide/mappings.html
llms_txt: https://docs.pingidentity.com/pingidm/llms.txt
docs_for_agents: https://developer.pingidentity.com/build-with-ai/docs-for-agents.md
superseded_by: https://docs.pingidentity.com/pingidm/8.1/synchronization-guide/mappings.html
---

# Resource mapping

A synchronization mapping specifies a relationship between objects and their attributes in two data stores. The following example shows a typical attribute mapping, between objects in an external LDAP directory and an IDM managed user data store:

```
"source": "lastName",
"target": "sn"
```

In this case, the `lastName` source attribute is mapped to the `sn` (surname) attribute in the target LDAP directory.

The core synchronization configuration is defined in the mapping configuration *(tooltip: You can manage the mapping configuration over REST at the config/sync endpoint, directly in the conf/sync.json file, or in individual conf/mapping-\<mappingName>.json files.)*.

You can define a single file with all your mappings (`conf/sync.json`), or a separate file per mapping. Individual mapping files are named `mapping-mappingName.json`; for example, `mapping-managedUser_systemCsvfileAccounts.json`. Individual mapping files can be useful if your deployment includes many mappings that are difficult to manage in a single file. You can also use a combination of individual mapping files and a monolithic `sync.json` file, particularly if you are adding mappings to an existing deployment.

If you use a single `sync.json` file, mappings are processed in the order in which they appear within that file. If you use multiple mapping files, mappings are processed according to the `syncAfter` property in the mapping. The following example indicates that this particular mapping must be processed after the `managedUser_systemCsvfileAccount` mapping:

```json
  "source" : "managed/user",
  "target" : "system/csvfile/account",
  "syncAfter" : [ "managedUser_systemCsvfileAccount" ],
```

If you use a combination of `sync.json` and individual mapping files, the synchronization engine processes the mappings in `sync.json` first (in order), and then any mappings specified in the individual mapping files, according to the `syncAfter` property in each mapping.

For a list of *all* mappings, use the following request:

```
curl \
--header "X-OpenIDM-Username: openidm-admin" \
--header "X-OpenIDM-Password: openidm-admin" \
--header "Accept-API-Version: resource=1.0" \
--request GET \
"http://localhost:8080/openidm/sync/mappings?_queryFilter=true"
```

This call returns the mappings in the order in which they will be processed.

|   |                                                                                                                                                         |
| - | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
|   | The admin UI only shows the mappings configured in the `sync.json` file. Do not use the admin UI to add or change mappings in individual mapping files. |

Mappings are always defined from a *source* resource to a *target* resource. To configure bidirectional synchronization, you must define two mappings. For example, to configure bidirectional synchronization between an LDAP server and an IDM repository, you would define the following two mappings:

* LDAP Server > IDM Repository

* IDM Repository > LDAP Server

Bidirectional mappings can include a `links` property that lets you reuse the links established between objects, for both mappings. For more information, see [Reuse Links Between Mappings](reusing-links.html).

You can update a mapping while the server is running. To avoid inconsistencies between data stores, do not update a mapping while a reconciliation is in progress *for that mapping*.