Label Studio Task Format

Label Studio JSON format of annotated tasks

When you annotate data, Label Studio stores the output in JSON format. The raw JSON structure of each completed task uses the following example: 

{
    "id": 1,
    "created_at":"2021-03-09T21:52:49.513742Z",
    "updated_at":"2021-03-09T22:16:08.746926Z",
    "project":83,

    "data": {
        "image": "https://example.com/opensource/label-studio/1.jpg"
    },

    "annotations": [
        {
            "id": "1001",
            "result": [
                {
                    "from_name": "tag",
                    "id": "Dx_aB91ISN",
                    "source": "$image",
                    "to_name": "img",
                    "type": "rectanglelabels",
                    "value": {
                        "height": 10.458911419423693,
                        "rectanglelabels": [
                            "Moonwalker"
                        ],
                        "rotation": 0,
                        "width": 12.4,
                        "x": 50.8,
                        "y": 5.869797225186766
                    }
                }
            ],
            "was_cancelled":false,
            "ground_truth":false,
            "created_at":"2021-03-09T22:16:08.728353Z",
            "updated_at":"2021-03-09T22:16:08.728378Z",
            "lead_time":4.288,
            "result_count":0,
            "task":1,
            "completed_by":10
        }
    ],

    "predictions": [
        {
            "created_ago": "3 hours",
            "model_version": "model 1",
            "result": [
                {
                    "from_name": "tag",
                    "id": "t5sp3TyXPo",
                    "source": "$image",
                    "to_name": "img",
                    "type": "rectanglelabels",
                    "value": {
                        "height": 11.612284069097889,
                        "rectanglelabels": [
                            "Moonwalker"
                        ],
                        "rotation": 0,
                        "width": 39.6,
                        "x": 13.2,
                        "y": 34.702495201535505
                    }
                }
            ]
        },
        {
            "created_ago": "4 hours",
            "model_version": "model 2",
            "result": [
                {
                    "from_name": "tag",
                    "id": "t5sp3TyXPo",
                    "source": "$image",
                    "to_name": "img",
                    "type": "rectanglelabels",
                    "value": {
                        "height": 33.61228406909789,
                        "rectanglelabels": [
                            "Moonwalker"
                        ],
                        "rotation": 0,
                        "width": 39.6,
                        "x": 13.2,
                        "y": 54.702495201535505
                    }
                }
            ]
        }
    ]
}

Relevant JSON property descriptions

Review the full list of JSON properties in the API documentation.

JSON property name Description
id Identifier for the labeling task from the dataset.
data Data copied from the input data task format. See the documentation for Task Format.
project Identifier for a specific project in Label Studio.
annotations Array containing the labeling results for the task.
annotations.id Identifier for the completed task.
annotations.lead_time Time in seconds to label the task.
annotations.result Array containing the results of the labeling or annotation task.
result.id Identifier for the specific annotation result for this task.
result.from_name Name of the tag used to label the region. See control tags.
result.to_name Name of the object tag that provided the region to be labeled. See object tags.
result.type Type of tag used to annotate the task.
result.value Tag-specific value that includes details of the result of labeling the task. The value structure depends on the tag for the label. For more information, see Explore each tag.
annotations.completed_by User ID of the user that created the annotation. Matches the list order of users on the People page on the Label Studio UI.
annotations.was_cancelled Boolean. Details about whether or not the annotation was skipped, or cancelled.
drafts Array of draft annotations. Follows similar format as the annotations array. Included only for tasks exported as a snapshot from the UI or using the API.
predictions Array of machine learning predictions. Follows the same format as the annotations array, with one additional parameter.
predictions.score The overall score of the result, based on the probabilistic output, confidence level, or other.

In this article

  1. Label Studio JSON format of annotated tasks