# Get a Value for an Issue Custom Field

Use the YouTrack REST API to retrieve the current value of a specific custom field in an issue.

## Summary

To get the value of a specific custom field in an issue, send a `GET` request to the issue custom field endpoint:

```
/api/issues/{issueID}/customFields/{fieldID}[?fields={list of attributes}]
```

## Additional Information

To form a list of value attributes, refer to the list of supported attributes for a value entity depending on the `$type` of the target custom field in an issue.

For fields where `value` stores a primitive value, for example a `string` field with the `SimpleIssueCustomField` `$type`, request the `value` attribute directly. Use nested attributes like `value(name)` only when the field value is an entity or a collection of entities.

## Step-by-Step

Procedure:

1. Get the list of issues in a target project. Also, let's request the list of available custom fields with their names.

```CURL
curl -X GET 'https://example.youtrack.cloud/api/issues?query=in:SP&fields=id,idReadable,summary,customFields(id,projectCustomField(field(name)))' \
-H 'Accept: application/json' \
-H 'Authorization: Bearer <YouTrack_token>'
```

The `query` request parameter lets us filter the list of issues by the target project, in the sample the projects `shortName` is `SP`.

In the `fields` request parameter, we instruct the server to return the following attributes for each issue found:

* `id` and `idReadable` - both database entity ID and an ID of the issue in the project, respectively.

* `summary` - issue's summary may help to identify the target issue.

* `customFields` - a list of custom fields for each issue. To help us identify the target custom field, we also request the name of each field which is defined through the project custom field and its "prototype" - the generic custom field.

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

```JSON
[
  {
    "summary": "Issue from REST #1",
    "idReadable": "SP-8",
    "customFields": [
      {
        "projectCustomField": {
          "field": {
            "name": "Priority",
            "$type": "CustomField"
          },
          "$type": "EnumProjectCustomField"
        },
        "id": "92-1",
        "$type": "SingleEnumIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Type",
            "$type": "CustomField"
          },
          "$type": "EnumProjectCustomField"
        },
        "id": "92-2",
        "$type": "SingleEnumIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "State",
            "$type": "CustomField"
          },
          "$type": "StateProjectCustomField"
        },
        "id": "92-3",
        "$type": "StateIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Assignee",
            "$type": "CustomField"
          },
          "$type": "UserProjectCustomField"
        },
        "id": "94-0",
        "$type": "SingleUserIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Subsystem",
            "$type": "CustomField"
          },
          "$type": "OwnedProjectCustomField"
        },
        "id": "92-0",
        "$type": "SingleOwnedIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Fix versions",
            "$type": "CustomField"
          },
          "$type": "VersionProjectCustomField"
        },
        "id": "92-4",
        "$type": "MultiVersionIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Affected versions",
            "$type": "CustomField"
          },
          "$type": "VersionProjectCustomField"
        },
        "id": "92-5",
        "$type": "MultiVersionIssueCustomField"
      },
      {
        "projectCustomField": {
          "field": {
            "name": "Fixed in build",
            "$type": "CustomField"
          },
          "$type": "BuildProjectCustomField"
        },
        "id": "92-6",
        "$type": "SingleBuildIssueCustomField"
      }
    ],
    "id": "2-7",
    "$type": "Issue"
  },
  {
    "summary": "Sprint 3. Task 2",
    "idReadable": "SP-38",
    "customFields": [
      ...
    ],
    "id": "2-42",
    "$type": "Issue"
  },
  {
    "summary": "Sprint3. Task 1",
    "idReadable": "SP-37",
    "customFields": [
      ...
    ],
    "id": "2-40",
    "$type": "Issue"
  },
  ...
]
```

2. Locate the ID of the target issue. For the sample, let's take the issue `SP-8` with the entity id `2-7`.

3. Locate the ID of a target custom field. Let's get the current State of the issue. In the sample, the ID of the State field is `92-3`.

4. Form a list of attributes that you want to get for the State field.

A list of supported attributes for a custom field depends entirely on its type.

A State field has `$type` of `StateIssueCustomField`. It binds a project custom field of the type `StateProjectCustomField` and a value. A [StateProjectCustomField](api-entity-StateProjectCustomField.html) uses a bundle of values of the type [StateBundle](api-entity-StateBundle.html). And a `StateBundle` stores values of the type [StateBundleElement](api-entity-StateBundleElement.html). Thus, to form a list of attributes that we want to get for the current value of the State field, we need to check the JSON schema and see what attributes the [StateBundleElement](api-entity-StateBundleElement.html) entity contains.

For the sample, we picked these:

| Attribute | Description |
| --- | --- |
| `name` | The name of the value. It represents the actual State that users see in UI: Open, In Progress, Fixed, and so on. |
| `localizedName` | If the server does not use the default locale, this attribute stores the name of the value in the selected locale. |
| `isResolved` | Indicates if the value - the state - is considered as resolved. |
| `id` | The entity ID of the value. |

To verify that we get the correct field in the sample, we also request the name of the field and its ID.

So, when we put together all the attributes that we want to receive from the server, the request parameter `fields` looks as follows:

```CURL
fields=id,projectCustomField(id,field(name)),value(id,isResolved,localizedName,name)
```

5. Now that we collected all the data that is required for the request, this is the resulting request for the field value:

```CURL
curl -X GET \
'https://example.youtrack.cloud/api/issues/SP-8/customFields/92-3?fields=id,projectCustomField(id,field(id,name)),value(id,isResolved,localizedName,name)' \
-H 'Accept: application/json' \
-H 'Authorization: Bearer <YouTrack_token>'
```

For this request, the server returns the following response body:

```JSON
{
    "projectCustomField": {
        "field": {
            "name": "State",
            "id": "58-3",
            "$type": "CustomField"
        },
        "id": "92-3",
        "$type": "StateProjectCustomField"
    },
    "value": {
        "isResolved": true,
        "localizedName": null,
        "name": "Fixed",
        "id": "69-7",
        "$type": "StateBundleElement"
    },
    "id": "92-3",
    "$type": "StateIssueCustomField"
}
```

6. If the target custom field stores a string value, request `value` without nested attributes. String fields use `SimpleIssueCustomField`, and their `value` is returned as a JSON string.

```CURL
curl -X GET \
'https://example.youtrack.cloud/api/issues/SP-8/customFields/92-7?fields=id,projectCustomField(id,field(id,name)),value' \
-H 'Accept: application/json' \
-H 'Authorization: Bearer <YouTrack_token>'
```

For a string field, the response body looks like this:

```JSON
{
    "projectCustomField": {
        "field": {
            "name": "Requester email",
            "id": "58-7",
            "$type": "CustomField"
        },
        "id": "92-7",
        "$type": "SimpleProjectCustomField"
    },
    "value": "test@example.com",
    "id": "92-7",
    "$type": "SimpleIssueCustomField"
}
```