Create an Estimate Item

  https://api.constructiononline.com/api/v2/EstimateItems?subcatID= {subcatID} 

This endpoint allows users to create a new estimate item for an existing estimate in their ConstructionOnline company account. The estimate item must be created for a specific estimate subcategory within an existing estimate. If an estimate subcategory ID is not included in the URL of the request, the estimate item will fail to be created. This endpoint will not create a new estimate item if the ConstructionOnline estimate structure is locked.

The new estimate item will be automatically assigned a unique numerical ID called 'ID', which will be used for any future references. The only required property for creation is NAME; all other properties are optional and can be entered during item creation or updated at a later time. If successful, the endpoint will return a record of the newly created estimate item with the included properties. 

• Requests
• Responses

Requests

subcatID: integer

• Unique identifier for the estimate subcategory. This is required for creation.

Subcategory Info: JSON 

• Properties to be added to the estimate item.

• Allowed properties: NAME (required), DESCRIPTION, COST_CODE, COST_CODE_ID, TRAFFIC_COLOR, BID_NOTES, NOTES_TEAMLINK, NOTES_BID, FIELD_NOTES, NOTES_CLIENTLINK, NOTES_FIELD, GENERAL_NOTES, NOTES_GENERAL, CLASSIFICATION, STATUS, UNIT, QTY, RATE_QTY, UNIT_COST, RATE, FIVE_COLUMN_MATERIAL, FIVE_COLUMN_LABOR, FIVE_COLUMN_EQUIPMENT, FIVE_COLUMN_SUB, FIVE_COLUMN_OTHER, LINE_ITEM_MARKUP, LINE_ITEM_MARKUP_TYPE, ADJUSTMENT, ACTUAL, COMMITTED_COSTS, INVOICED_AMOUNTS

Individual properties for creation should be entered as JSON key-value pairs, as seen below:

{
   "NAME": "Slab concrete - place",
   "COST_CODE_ID": 12000,
   "CLASSIFICATION": 3,
   "UNIT_NAME": "CY",
   "QTY": 120,
   "UNIT_COST": 85,
   "GENERAL_NOTES": "120 CY placed"
}

C#

/* replace {username} with the email address for your ConstructionOnline account
           {password} with your ConstructionOnline password
           {apikey} with your provided API key 
           {subcatID} with the associated estimate category's ID */
        

public string MakeRequest(string endpoint, string payload) {
     string username = {username};
     string password = {password};
     string apiKey = {apikey};
     string response = "";
      var handler = new HttpClientHandler() { AutomaticDecompression = System.Net.DecompressionMethods.GZip };
          using (HttpClient client = new HttpClient(handler)) {
           client.BaseAddress = new Uri("http://api.constructiononline.com");
           client.DefaultRequestHeaders.Accept.Clear();
           client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
           client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", System.Convert.ToBase64String(System.Text.Encoding.GetEncoding("ISO-8859-1").GetBytes(username + ":" + password)));
           client.DefaultRequestHeaders.Add("APIKey", apiKey);
           client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip");
           HttpContent content = new StringContent(payload, System.Text.Encoding.UTF32, "application/json");
           response = client.PostAsync(endpoint, content).Result.ToString();
            }
      return response;
            }

     MakeRequest("api/v2/EstimateItems?subcatID={subcatID}");

Python

#replace {username} with the email address for your ConstructionOnline account
#{password} with your ConstructionOnline password
#{apikey} with your provided API key
#{subcatID} with the associated estimate category's ID 

import base64, requests, json
#Global Variables
  apikey = {apikey}
  username = {username}
  password = {password}

#Functions
  def makeRequest(endpoint, payload):
       url = "https://api.constructiononline.com/" + endpoint
       userPass = username + ":" + password    
       headers = {
                    "APIKey": apikey,
                    "Accept-Encoding": "gzip, deflate, br",
                    "Authorization": "Basic " + base64.b64encode(userPass.encode()).decode(),
                }
       response = requests.request("POST", url, headers=headers, data=payload)
       return json.dumps(json.loads(response.text), indent=2)   
#Main Program 
print(makeRequest("api/v2/EstimateItems?subcatID={subcatID}"))

JavaScript

/* replace {username} with the email address for your ConstructionOnline account
           {password} with your ConstructionOnline password
           {apikey} with your provided API key 
           {subcatID} with the associated estimate category's ID */
     

 username = '{username}';
 password = '{password}';
 apikey = '{apikey}';

 function makeRequest(endpoint, payload) {
          auth = btoa('${username}:${password}');
          var myHeaders = new Headers();
          myHeaders.append("APIKey", apikey);
          myHeaders.append("Accept-Encoding", "gzip, deflate, br");
          myHeaders.append("Authorization", "Basic ${auth}");

                var requestOptions = {
                    method: 'POST',
                    body: '',
                    headers: myHeaders,
                    redirect: 'follow'
                };
                fetch("https://api.constructiononline.com/" + endpoint, requestOptions)
                    .then(response => response.text())
                    .then(result => console.log(result))
                    .catch(error => console.log('error', error));
                return response;
            };
 makeRequest("api/v2/EstimateItems?subcatID={subcatID}");

Responses

 200: Success

A successful request will return a 200 response with a record of the newly created estimate item in the body.

A sample response and property definitions can be found here.

 404: Error

The server was not able to locate the resource specified in the request.

 429: Error

The user has surpassed the request rate limit for the hour, day, week, or month.

 500: Error

There was an internal server error and the server was unable to complete the request.

Last updated: Sep 22, 2026