Add a subtask to a task

Adds an existing task as a subtask to the specified parent task. Subtasks allow you to break down complex tasks into smaller, more manageable units with clear assignments and better tracking. Each subtask works like its own ticket with its own description, assignee, priority, and status. The parent task identifier can be either a UUID or a numeric shortNumber. The subtask must exist and be accessible to the user. Requires Tasks.editAnyTitleAndDescription permission.

POST/tasks/{identifier}/subtasks

Authorization

AuthorizationOAuth2 access token · headerrequired

Scopes:api:write

AuthorizationBearer token (JWT) · headerrequired

Path parameters

identifierstringrequired

Parent task UUID or numeric shortNumber

Query parameters

fieldsToReturnstring

Comma-separated list of top-level response fields to return. Overrides the endpoint compact default unless responseShape=full is used.

responseShapestring

Advanced override. Omit for the endpoint compact default. Use full only when you need the complete endpoint response, including nested fields that are not selectable with fieldsToReturn.

Allowed:compactfull

Header parameters

LT-Response-Shapestring

Advanced override. Set to full only when you need the complete endpoint response, including nested fields that are not selectable with fieldsToReturn.

Allowed:full

Request body

requiredapplication/json

subtaskIdstringrequired

UUID of an existing task to add as a subtask to the parent task. The subtask must exist in the workspace and be accessible to the user. The subtask will be linked to the parent task specified in the URL path.

Responses

200Subtask added successfully

accountableobject

Accountable user details

accountableIdstring

Accountable user ID

assignedToobject

Assigned user details

assignedToIdstring

Assigned user ID

billedbooleanrequired

Whether task is billed

childSpentTimenumberrequired

Child tasks spent time in minutes

commentsany[][]required

Task comments; each `body` is HTML and may contain the same embedded `appImage` / `appFile` / `appVideo` divs with `fileId` as the task description. Fetch binaries via authenticated `/api/public/workspace/files/{fileId}` with the same Public API Bearer token when needed.

componentItemIdobject

Component item ID

createdAtstring<date-time>required

Task creation timestamp

customFieldsobjectrequired

Custom fields values

deadlinestring<date-time>

Task deadline

descriptionstringrequired

Task description in HTML. May include embedded assets as elements such as `<div data-type="appImage" fileId="…" filename="…">` (images), `appFile`, or `appVideo`—binary content is not embedded; use authenticated GET `{appOrigin}/api/public/workspace/files/{fileId}` with the same Public API Bearer token to retrieve it.

emailDetailsobject

Email details

emailSendErrorstring

Email send error message

emailSendErrorCodestring

Email send error code

emailSendFailedAtstring<date-time>

Email send failed timestamp

emailSendFailedToany[][]

Email send failed recipients

enableSupportContingentbooleanrequired

Enable support contingent

estimatedTimenumber

Estimated time in hours

guestAccessbooleanrequired

Guest access enabled for organization members

historyany[][]required

Task history entries

iconobject

Task icon identifier in the format `:icon_name:` (e.g., `:rocket:`, `:bug:`, `:memo:`). Can be null if no custom icon is set.

iconIsGeneratingbooleanrequired

Whether icon is being generated by AI

idstringrequired

Task ID (UUID)

isChangeRequestbooleanrequired

Whether task is a change request

isParticipantbooleanrequired

Whether current user is a participant

notificationSettingsobjectrequired

Notification settings

parentTaskIdobject

Parent task ID for subtasks

participantsCountnumberrequired

Number of participants

participantsListany[][]required

List of participant user IDs

priorityobjectrequired

Task priority (TaskPriority enum)

productsany[][]required

Task products

projectobjectrequired

Project information

projectIdstringrequired

Project ID

quotationsany[][]required

Express quotations

shortNumbernumberrequired

Task short number (workspace-scoped)

skipFromBillingboolean

Skip from billing

spentTimenumberrequired

Total spent time in minutes

statusIdstringrequired

Task status ID

subTasksIdsany[][]required

Child task IDs

summarystring

Task summary

summaryIsGeneratingbooleanrequired

Whether summary is being generated by AI

tagsany[][]required

Task tags

titlestringrequired

Task title

titleIsGeneratingbooleanrequired

Whether title is being generated by AI

typeIdstringrequired

Task type ID

userIdstringrequired

Creator user ID

400Invalid identifier format or validation errors

401Unauthorized - Invalid or missing authentication token

403Access denied: No access to project or task not editable

404Task not found

Request

curl -X POST "https://leadtime.app/api/public/tasks/550e8400-e29b-41d4-a716-446655440000%20or%20123/subtasks" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
  "subtaskId": "550e8400-e29b-41d4-a716-446655440000"
}'

const response = await fetch("https://leadtime.app/api/public/tasks/550e8400-e29b-41d4-a716-446655440000%20or%20123/subtasks", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_ACCESS_TOKEN",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
  "subtaskId": "550e8400-e29b-41d4-a716-446655440000"
})
});

import requests

response = requests.post(
    "https://leadtime.app/api/public/tasks/550e8400-e29b-41d4-a716-446655440000%20or%20123/subtasks",
    headers={
        "Authorization": "Bearer YOUR_ACCESS_TOKEN",
        "Content-Type": "application/json"
    },
    json={
  "subtaskId": "550e8400-e29b-41d4-a716-446655440000"
},
)

Response

{
  "accountable": {},
  "accountableId": "string",
  "assignedTo": {},
  "assignedToId": "string",
  "billed": true,
  "childSpentTime": 0,
  "comments": [
    [
      null
    ]
  ],
  "componentItemId": {},
  "createdAt": "2024-01-01T00:00:00Z",
  "customFields": {},
  "deadline": "2024-01-01T00:00:00Z",
  "description": "string",
  "emailDetails": {},
  "emailSendError": "string",
  "emailSendErrorCode": "string",
  "emailSendFailedAt": "2024-01-01T00:00:00Z",
  "emailSendFailedTo": [
    [
      null
    ]
  ],
  "enableSupportContingent": true,
  "estimatedTime": 0,
  "guestAccess": true,
  "history": [
    [
      null
    ]
  ],
  "icon": {},
  "iconIsGenerating": true,
  "id": "string",
  "isChangeRequest": true,
  "isParticipant": true,
  "notificationSettings": {},
  "parentTaskId": {},
  "participantsCount": 0,
  "participantsList": [
    [
      null
    ]
  ],
  "priority": {},
  "products": [
    [
      null
    ]
  ],
  "project": {},
  "projectId": "string",
  "quotations": [
    [
      null
    ]
  ],
  "shortNumber": 0,
  "skipFromBilling": true,
  "spentTime": 0,
  "statusId": "string",
  "subTasksIds": [
    [
      null
    ]
  ],
  "summary": "string",
  "summaryIsGenerating": true,
  "tags": [
    [
      null
    ]
  ],
  "title": "string",
  "titleIsGenerating": true,
  "typeId": "string",
  "userId": "string"
}