Update Checklist Item with task.checklistitem.update

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Scope: task

Who can execute the method:

  • any user with edit access to the task
  • Creator, Performer, and Participants of the task

The method task.checklistitem.update modifies an existing checklist item.

You can check the permissions to modify the item using the method task.checklistitem.isactionallowed.

Method Parameters

Pass parameters in the request according to the order in the table. If the order is violated, the request will return an error or update a different item.

Required parameters are marked with *

Name
type

Description

TASKID*
integer

Task identifier.

The task identifier can be obtained when creating a new task or using the get task list method.

ITEMID*
integer

Checklist item identifier.

The item identifier can be obtained when adding a new item or using the get checklist item list method.

FIELDS*
object

Object with checklist item fields. Pass only the fields you want to change

FIELDS Parameter

Name
type

Description

TITLE
string

Text of the checklist item.

If PARENT_ID is passed with a value of 0, then TITLE is the name of the checklist.

SORT_INDEX
integer

Sort index. The lower the value, the higher the item in the list or sublist.

IS_COMPLETE
string

Status of the item. Possible values:

  • Y — completed
  • N — not completed

Also accepts true and false. When the status changes, the system fills in the TOGGLED_BY and TOGGLED_DATE fields.

IS_IMPORTANT
string

Mark indicating that the item is important. Possible values:

  • Y — important
  • N — regular

Also accepts true and false.

MEMBERS
object

Object describing the participants of the checklist item. Key — user identifier, value — object with the participant type parameter TYPE. Possible participant type values:

  • 'TYPE': 'A' — participant
  • 'TYPE': 'U' — observer

The MEMBERS field is completely replaced. To retain current participants, pass them along with new values. If a participant has any other TYPE, the method skips the entire MEMBERS without an error.

The system will add checklist item participants to the task in the same roles.

PARENT_ID
integer

Identifier of the parent item. Use for nested checklists.

  • If PARENT_ID is passed with a value of 0, the system will create a new checklist in the task.
  • If there is no item with the specified PARENT_ID, the item is saved with this PARENT_ID and does not belong to any checklist. Pass only identifiers of existing items in the task.
  • If the root checklist item is moved under another checklist item, it will move along with its sub-items while maintaining the hierarchy. The checklists will merge into one.

Code Examples

How to Use Examples in Documentation

curl -X POST \
        -H "Content-Type: application/json" \
        -H "Accept: application/json" \
        -d '{"TASKID":13,"ITEMID":475,"FIELDS":{"TITLE":"Prepare report","PARENT_ID":447,"SORT_INDEX":100,"IS_COMPLETE":"N","IS_IMPORTANT":"N","MEMBERS":{"547":{"TYPE":"A"},"125":{"TYPE":"U"}}}}' \
        https://**put_your_bitrix24_address**/rest/**put_your_user_id_here**/**put_your_webhook_here**/task.checklistitem.update
        
curl -X POST \
        -H "Content-Type: application/json" \
        -H "Accept: application/json" \
        -d '{"TASKID":13,"ITEMID":475,"FIELDS":{"TITLE":"Prepare report","PARENT_ID":447,"SORT_INDEX":100,"IS_COMPLETE":"N","IS_IMPORTANT":"N","MEMBERS":{"547":{"TYPE":"A"},"125":{"TYPE":"U"}}},"auth":"**put_access_token_here**"}' \
        https://**put_your_bitrix24_address**/rest/task.checklistitem.update
        
// This snippet is an ES module: top-level await requires type="module" or a bundler.
        // $b24 is an already-initialized SDK instance (see the SDK "Get started" guide).
        import { Text } from '@bitrix24/b24jssdk'
        import type { B24Frame } from '@bitrix24/b24jssdk'
        
        declare const $b24: B24Frame
        
        // Shape of the payload returned in result (match the "response handling" section of the page)
        type ChecklistItemUpdateResult = null
        
        try {
          const response = await $b24.actions.v2.call.make<ChecklistItemUpdateResult>({
            method: 'task.checklistitem.update',
            params: {
              TASKID: 13,
              ITEMID: 475,
              FIELDS: {
                TITLE: 'Prepare report',
                PARENT_ID: 447,
                SORT_INDEX: 100,
                IS_COMPLETE: 'N',
                IS_IMPORTANT: 'N',
                MEMBERS: {
                  547: { TYPE: 'A' },
                  125: { TYPE: 'U' },
                },
              },
            },
            requestId: Text.getUuidRfc4122()
          })
        
          // The payload is available only on a successful response
          if (!response.isSuccess) {
            console.error(response.getErrorMessages().join('; '))
          } else {
            const result = response.getData()!.result
            console.info('Checklist item updated successfully, result:', result)
          }
        } catch (error) {
          // Thrown on transport or SDK failures (AjaxError, SdkError, etc.)
          console.error(error)
        }
        
<!-- Load the SDK (UMD build); it is exposed as the global B24Js -->
        <script src="https://unpkg.com/@bitrix24/b24jssdk@1/dist/umd/index.min.js"></script>
        <script>
          async function updateChecklistItem() {
            try {
              // Initialize the SDK inside a Bitrix24 frame
              const $b24 = await B24Js.initializeB24Frame()
        
              const response = await $b24.actions.v2.call.make({
                method: 'task.checklistitem.update',
                params: {
                  TASKID: 13,
                  ITEMID: 475,
                  FIELDS: {
                    TITLE: 'Prepare report',
                    PARENT_ID: 447,
                    SORT_INDEX: 100,
                    IS_COMPLETE: 'N',
                    IS_IMPORTANT: 'N',
                    MEMBERS: {
                      547: { TYPE: 'A' },
                      125: { TYPE: 'U' },
                    },
                  },
                },
                requestId: B24Js.Text.getUuidRfc4122()
              })
        
              // The payload is available only on a successful response
              if (!response.isSuccess) {
                console.error(response.getErrorMessages().join('; '))
                return
              }
        
              const result = response.getData().result
              console.info('Checklist item updated successfully, result:', result)
            } catch (error) {
              // Thrown on transport or SDK failures (AjaxError, SdkError, etc.)
              console.error(error)
            }
          }
        
          document.addEventListener('DOMContentLoaded', updateChecklistItem)
        </script>
        
from b24pysdk.errors import BitrixAPIError, BitrixSDKException
        
        fields = {
            "TITLE": "Prepare the report",
            "PARENT_ID": 447,
            "SORT_INDEX": 100,
            "IS_COMPLETE": "N",
            "IS_IMPORTANT": "N",
            "MEMBERS": {
                "547": {
                    "TYPE": "A",
                },
                "125": {
                    "TYPE": "U",
                },
            },
        }
        
        try:
            bitrix_response = client.task.checklistitem.update(
                task_id=13,
                item_id=475,
                fields=fields,
            ).response
            result = bitrix_response.result
            print(result)
        except BitrixAPIError as error:
            print(
                "Bitrix API error",
                f"error: {error.error}",
                f"error_description: {error.error_description}",
                sep="\n",
            )
        except BitrixSDKException as error:
            print(f"Bitrix SDK error: {error.message}")
        except Exception as error:
            print(f"Unexpected error: {error}")
        
try {
            $response = $b24Service
                ->core
                ->call(
                    'task.checklistitem.update',
                    [
                        'TASKID' => 13,
                        'ITEMID' => 475,
                        'FIELDS' => [
                            'TITLE' => 'Prepare report',
                            'PARENT_ID' => 447,
                            'SORT_INDEX' => 100,
                            'IS_COMPLETE' => 'N',
                            'IS_IMPORTANT' => 'N',
                            'MEMBERS' => [
                                547 => [
                                    'TYPE' => 'A'
                                ],
                                125 => [
                                    'TYPE' => 'U'
                                ]
                            ]
                        ]
                    ]
                );
        
            $result = $response
                ->getResponseData()
                ->getResult();
        
            echo 'Success: ' . print_r($result, true);
            processData($result);
        
        } catch (Throwable $e) {
            error_log($e->getMessage());
            echo 'Error updating checklist item: ' . $e->getMessage();
        }
        
BX24.callMethod(
            'task.checklistitem.update',
            {
                'TASKID': 13,
                'ITEMID': 475,
                'FIELDS': {
                    'TITLE': 'Prepare report',
                    'PARENT_ID': 447,
                    'SORT_INDEX': 100,
                    'IS_COMPLETE': 'N',
                    'IS_IMPORTANT': 'N',
                    'MEMBERS': {
                        547: {
                            'TYPE': 'A'
                        },
                        125: {
                            'TYPE': 'U'
                        }
                    }
                }
            },
            function(result){
                console.info(result.data());
                console.log(result);
            }
        );
        
require_once('crest.php');
        
        $result = CRest::call(
            'task.checklistitem.update',
            [
                'TASKID' => 13,
                'ITEMID' => 475,
                'FIELDS' => [
                    'TITLE' => 'Prepare report',
                    'PARENT_ID' => 447,
                    'SORT_INDEX' => 100,
                    'IS_COMPLETE' => 'N',
                    'IS_IMPORTANT' => 'N',
                    'MEMBERS' => [
                        547 => [
                            'TYPE' => 'A'
                        ],
                        125 => [
                            'TYPE' => 'U'
                        ]
                    ]
                ]
            ]
        );
        
        echo '<PRE>';
        print_r($result);
        echo '</PRE>';
        
// client and ctx are already created — see the Go SDK section
        res, err := client.Core().Call(ctx, "task.checklistitem.update", b24.Params{
        	"TASKID": 13,
        	"ITEMID": 475,
        	"FIELDS": b24.Params{
        		"TITLE":        "Prepare report",
        		"PARENT_ID":    447,
        		"SORT_INDEX":   100,
        		"IS_COMPLETE":  "N",
        		"IS_IMPORTANT": "N",
        		"MEMBERS": b24.Params{
        			"547": b24.Params{
        				"TYPE": "A",
        			},
        			"125": b24.Params{
        				"TYPE": "U",
        			},
        		},
        	},
        })
        if err != nil {
        	return fmt.Errorf("task.checklistitem.update: %w", err)
        }
        
        // On success, result is null
        fmt.Printf("%s\n", res.Result)
        

Response Handling

HTTP Status: 200

{
            "result": null,
            "time": {
                "start": 1762432505,
                "finish": 1762432505.206889,
                "duration": 0.20688891410827637,
                "processing": 0,
                "date_start": "2025-11-06T15:35:05+01:00",
                "date_finish": "2025-11-06T15:35:05+01:00",
                "operating_reset_at": 1762433105,
                "operating": 0.13953208923339844
            }
        }
        

Returned Data

Name
type

Description

result
null

Returns null if the checklist item is successfully updated.

The method also returns null if you pass an empty FIELDS or an empty TITLE: the item does not change in this case. To check the result, retrieve the item using the task.checklistitem.get method.

time
time

Information about the request execution time.

Error Handling

HTTP Status: 400

{
            "error":"ERROR_CORE",
            "error_description":"TASKS_ERROR_EXCEPTION_#4; Cannot edit the task due to insufficient permissions; 4/TE/ACTION_NOT_ALLOWED<br>"
        }
        

Name
type

Description

error
string

String error code. It consists of digits, Latin letters, and underscores. It may arrive empty — in that case only error_description shows the reason

error_description
string

Error message for the developer. Do not show it to the end user without processing

Possible Error Codes

Code

Description

Value

ERROR_CORE

TASKS_ERROR_EXCEPTION_#4; Cannot edit the task due to insufficient permissions; 4/TE/ACTION_NOT_ALLOWED

The item has MEMBERS participants, but the user lacks permission to edit the task to add them to it. The item changes have already been saved.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#8; Incorrect value [] specified for field [ENTITY_ID] in item [, Prepare report]; 8/TE/ACTION_FAILED_TO_BE_PROCESSED

There is no item with the ITEMID identifier, or the parameters are passed out of order.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #0 (taskId) expected by method ctaskchecklistitem::update(), but not given.; 256/TE/WRONG_ARGUMENTS

Required parameter TASKID not provided.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #0 (taskId) for method ctaskchecklistitem::update() expected to be of type "integer", but given something else.; 256/TE/WRONG_ARGUMENTS

Incorrect value type for TASKID.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #1 (itemId) expected by method ctaskchecklistitem::update(), but not given.; 256/TE/WRONG_ARGUMENTS

Required parameter ITEMID not provided.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #1 (itemId) for method ctaskchecklistitem::update() expected to be of type "integer", but given something else.; 256/TE/WRONG_ARGUMENTS

Incorrect value type for ITEMID.

ERROR_CORE

TASKS_ERROR_ASSERT_EXCEPTION

The TASKID or ITEMID value is less than or equal to zero.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #2 (arFields) expected by method ctaskchecklistitem::update(), but not given.; 256/TE/WRONG_ARGUMENTS

Required parameter FIELDS not provided.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#8; Bitrix\Tasks\CheckList\Internals\CheckListTree::canAttach: Cannot create circular reference [261, 267]; 8/TE/ACTION_FAILED_TO_BE_PROCESSED

A subitem of the item being updated is passed in PARENT_ID.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#8; Bitrix\Tasks\CheckList\Internals\CheckListTree::canAttach: Cannot attach node to itself [261, 261]; 8/TE/ACTION_FAILED_TO_BE_PROCESSED

The identifier of the item itself is passed in PARENT_ID.

ERROR_CORE

TASKS_ERROR_EXCEPTION_#256; Param #2 (arFields) for method ctaskchecklistitem::update() must not contain key "ID".; 256/TE/WRONG_ARGUMENTS

FIELDS contains a field that cannot be changed. Only the fields from the FIELDS parameter table can be changed.

Statuses and System Error Codes

HTTP Status: 4xx, 5xx

The errors described below are returned by the REST API itself, not by the logic of a specific method. They can arrive in response to any method.

Status

Code
Error Message

Description

500

INTERNAL_SERVER_ERROR
Internal server error

An internal server error has occurred. Retry the call, and if the error persists, contact the server administrator or Bitrix24 technical support

500

ERROR_UNEXPECTED_ANSWER
Server returned an unexpected response

The server returned an unexpected response. Retry the call, and if the error persists, contact the server administrator or Bitrix24 technical support

503

QUERY_LIMIT_EXCEEDED
Too many requests

The request intensity limit has been exceeded

429

OPERATION_TIME_LIMIT
Method is blocked due to operation time limit

The method is blocked because the request resource intensity limit has been exceeded. The block is lifted automatically once the accumulated execution time of the method no longer exceeds the limit

401

NO_AUTH_FOUND
Wrong authorization data

The request contains no authorization data: neither an access token nor a webhook code was passed

401

INVALID_REQUEST
Https required

Methods are called over the HTTPS protocol only

401

OVERLOAD_LIMIT
REST API is blocked due to overload

The REST API is blocked due to overload. This is a manual individual block. To have it lifted, contact Bitrix24 technical support

401

ACCESS_DENIED
REST is available only on commercial plans

REST API access is not active for this account. In Bitrix24 Cloud, check the current plan or trial status: Vibe+ plans include REST API access, while Essentials plans do not. A webhook receives a different error message — REST is available only by subscription

401

INVALID_CREDENTIALS
Invalid request credentials

No active webhook with the specified user identifier and secret code was found

404

ERROR_METHOD_NOT_FOUND
Method not found!

No method with this name was found. The name is misspelled, the method does not exist in the REST API, or it is unavailable without the required scope

401

insufficient_scope
The request requires higher privileges than provided by the webhook token

The request requires broader permissions than the token has: for a webhook these are the permissions granted to it, for an application it is the scope. For an application, the error message ends with provided by the access token

401

expired_token
The access token provided has expired

The access token has expired

401

user_access_error
The user does not have access to the application

The application is installed, but the Bitrix24 administrator has granted access to it only to specific users

403

PORTAL_DELETED
Portal was deleted

The public part of the site is closed. To open it on an on-premise installation, disable the "Temporary closure of the public part of the site" option. Path to the setting: Desktop > Settings > Product Settings > Module Settings > Main Module > Temporary closure of the public part of the site

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