# Add a Value to a Set

Use the REST API to add a new value to a set of values for a custom field in a specific project. In the REST API, the entity that represents a set of values for a custom field is called a bundle.

## Summary

When you have all necessary entity IDs, you can add a new value to the bundle by sending a POST request to this endpoint:

```
/api/admin/projects/{project_id}/customFields/{field_id}/bundle/values
```

## Step-by-Step

Procedure:

1. Get the ID of the project where you want to add a value to the set. For instructions, see [Get a Project ID](api-usecase-get-project-id.html). This example uses the project `Test Project` with the entity ID `81-0`.

2. Get the [list of all custom fields](resource-api-admin-projects-projectID-customFields.html#get_all-ProjectCustomField-method) attached to the target project using the project ID you retrieved.

```CURL
curl -X GET 'https://example.youtrack.cloud/api/admin/projects/81-0/customFields?fields=id,field(name)' \
-H 'Accept: application/json' \
-H 'Authorization: Bearer <YouTrack_token>' \
-H 'Content-Type: application/json'
```

In the `fields` request parameter, you instruct the server to return the `ID` and `name` attributes of each custom field.

In the response to this request, the server returns the following data:

```JSON
[
    {
        "field": {
            "name": "Subsystem",
            "$type": "CustomField"
        },
        "id": "82-0",
        "$type": "OwnedProjectCustomField"
    },
    {
        "field": {
            "name": "Type",
            "$type": "CustomField"
        },
        "id": "82-2",
        "$type": "EnumProjectCustomField"
    },
    {
        "field": {
            "name": "State",
            "$type": "CustomField"
        },
        "id": "82-3",
        "$type": "StateProjectCustomField"
    },
    {
        "field": {
            "name": "Fix versions",
            "$type": "CustomField"
        },
        "id": "82-4",
        "$type": "VersionProjectCustomField"
    }
]
```

3. Locate the `ID` of the target custom field. This example uses the field `Fix versions` with the entity ID `82-4`.

4. To form the URL for the final POST request, you need to check the attributes of the target field type. You can find the field type in the response with the list of all project custom fields you got earlier.

In this case, the field `Fix versions` is of [VersionProjectCustomField](api-entity-VersionProjectCustomField.html) type. Since you want to update the field bundle, you need the `bundle` attribute.

5. A bundle as an entity has its own attributes which you can check according to the bundle type.

In this case, the bundle of a `VersionProjectCustomField` is a [VersionBundle](api-entity-VersionBundle.html). Since you want to update the set of its values, you need the `values` attribute.

6. Form the full request URL:

```
/api/admin/projects/81-0/customFields/82-4/bundle/values?fields=id,name
```

In the `fields` request parameter, you instruct the server to return the `ID` and the `name` of the value that you add.

7. To form a body for your POST request, you need to check the attributes of the element that you’re adding. In this case, a `VersionBundle` contains an array of `VersionBundleElements` as values, so you need to add one more `VersionBundleElement` to the array. The only attribute that you need to set is the name of the new value:

```JSON
{
    "name": "V.2.0",
    "$type": "VersionBundleElement"
}
```

Notice that you must include the `$type` parameter in each request. For more information about `$type` in POST requests, check the [documentation](api-concept-custom-fields.html#type-issue-custom-fields).

8. Add a new value to the bundle of the target custom field with a POST request:

```CURL
curl -X POST 'https://example.youtrack.cloud/api/admin/projects/81-0/customFields/82-4/bundle/values?fields=id,name' \
-H 'Accept: application/json' \
-H 'Authorization: Bearer <YouTrack_token>' \
-H 'Content-Type: application/json' \
-d '{"name": "V.2.0", "$type": "VersionBundleElement"}'
```

If the request is successful, you’ll get the following response:

```JSON
{
    "name":"V.2.0",
    "id":"103-433",
    "$type":"VersionBundleElement"
}
```

It contains the `ID`, `name`, and `type` of the added value.

As a result, you’ve added a new element to the set of values (bundle) for the `Fix versions` field in the `Test Project` project.

Following similar steps, you can also add new values to the sets of values for other field types: [BuildBundle](api-entity-BuildBundle.html), [EnumBundle](api-entity-EnumBundle.html), [OwnedBundle](api-entity-OwnedBundle.html), [StateBundle](api-entity-StateBundle.html).