Annotation Insights

Roboflow provides statistics on annotations associated with your workspace and projects. You can view annotation insights in the Roboflow dashboard and through the REST API.

On August 1st, 2023, we improved how annotation metrics are tracked. The Annotation Insights v2 endpoint provides annotation data from August 1st, 2023 and later.

REST API

To retrieve annotation insights for a workspace, make a GET request to the following endpoint:

https://api.roboflow.com/${WORKSPACE}/stats

This endpoint accepts the following URL parameters:

Parameter	Description	Required
api_key	API Authentication	Yes
startDate	Start date in YYYY-MM-DD format. Data available from 2023-08-01 onward.	Yes
endDate	End date in YYYY-MM-DD format.	Yes
project	Project slug (dataset URL) to filter results.	Optional
userId	User ID to filter results.	Optional

Example response:

{
    "data": [
        {
            "approved": 73,
            "boxesDrawn": 127,
            "imagesLabeled": 73,
            "projectId": "projectId123",
            "projectName": "My CV Project",
            "markedNull": 8,
            "modelAssisted": 1,
            "rejected": 2,
            "labelerId": "labelerId123",
            "workspaceId": "workspaceId123",
            "approvalRate": 97.26
        },
        {
            "approved": 0,
            "boxesDrawn": 10,
            "imagesLabeled": 5,
            "projectId": "projectId123",
            "projectName": "My CV Project",
            "markedNull": 0,
            "modelAssisted": 0,
            "rejected": 0,
            "labelerId": "labelerId456",
            "workspaceId": "workspaceId123",
            "approvalRate": null
        }
    ],
    "labelers": [
        {
            "displayName": "Lenny",
            "email": "[e-mail]",
            "id": "labelerId123"
        },
        {
            "displayName": "Dana",
            "email": "[e-mail]",
            "id": "labelerId456"
        }
    ],
    "stats": {
        "numImagesLabeled": 78,
        "numBoxesDrawn": 137,
        "numImagesMarkedNull": 8,
        "totalImagesUsingModelAssist": 1,
        "approvalRate": 97.26
    }
}

Annotation Insights Data Structure

This endpoint returns a payload with the following structure:

• data: Per-labeler metrics grouped by project. Each object represents one labeler's activity on a single project.

  • projectId: ID of the project (from session.datasetId).

  • projectName: Project name, resolved via getProjectsByIds.

  • projectType: Type of project (e.g., "object-detection").

  • labelerId: Unique ID of the labeler.

  • workspaceId: ID of the workspace this session belongs to.

  • imagesLabeled: Count of images where the labeler created, edited, deleted annotations, or marked them null.

  • boxesDrawn: Net number of annotations created (equals boxesAdded - boxesRemoved).

  • markedNull: Number of images explicitly marked as null by the labeler.

  • modelAssisted: Count of images where model assist was used.

  • approved: Count of images that were approved.

  • rejected: Count of rejection events for this labeler/project pairing. Each rejection is counted independently, even if the image was later approved.

  • approvalRate: First-pass acceptance rate - the percentage of reviewed images that were approved without ever being rejected. Returns null when no images were reviewed.

  • netBoxesAdded: Total of the number of new boxes created within each session (see note below)

  • netBoxesUpdated: Currently equivalent to boxesUpdated (included for consistency).

  • boxesAdded: Total number of annotations created.

  • boxesRemoved: Total number of annotations deleted.

  • boxesUpdated: Total number of annotations edited.

• labelers: Metadata for each labeler ID present in data.

  • Derived from unique labelerIds.

  • id: Labeler’s user ID.

  • displayName: Name from the user profile.

  • email: Email address.

    • For system labelers (e.g., autolabelservice), returns placeholder values.

• meta: Supplementary metadata.

  • notices: Array of disclaimers.

    • Currently includes a single item noting that metrics are available only after August 1, 2023.

• stats: Aggregated workspace-level totals across all sessions.

  • numImagesLabeled: Total count of unique labeled images.

  • numBoxesDrawn: Net annotations created across all sessions.

  • numImagesMarkedNull: Images marked null at least once.

  • totalImagesUsingModelAssist: Images labeled with model assistance.

  • numBoxesAdded: Total number of annotations created.

  • numBoxesRemoved: Total number of annotations deleted.

  • numBoxesUpdated: Total number of annotations edited.

  • netBoxesAdded: numBoxesAdded - numBoxesRemoved.

  • netBoxesUpdated: numBoxesUpdated (included for naming symmetry).

  • approvalRate: Aggregate first-pass acceptance rate across all labelers and projects - the percentage of reviewed images approved without ever being rejected. Returns null when no images were reviewed.

Because data[].imagesLabeled , in the per-labeler counts, records each session separately, the same image can be counted more than once if it was labeled on multiple days or by multiple labelers. The overall stats.numImagesLabeled field, however, is derived from combinedData and counts each unique image only once across the date range. This difference often explains why the total image count from the API may not exactly match what the UI displays, depending on which metric the UI uses (per-session vs. unique images).

netBoxesAdded: For each session, Roboflow counts boxes added (boxes that are present at the time the session ends; if a box is added, then removed before the session ends, it will not be included in the count) within that one session. The netBoxesAdded stat totals the net box additions (they do not match later deletions). It therefore equals the sum of “Total of the number of new boxes created within each session,” not the dataset’s final box count.