Create an Estimate Category

https://api.constructiononline.com/api/EstimateCategories?estimateID={estimateID}

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

The new estimate category 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 subcategory creation or updated at a later time. If successful, the endpoint will return a record of the newly created estimate category with the included properties.

Requests
Responses

Requests

estimateID: integer

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

Category Info: JSON

Properties to be added to the estimate category.

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, SUBCATS
- SUBCATS: array
  - Allowed properties: NAME (required), DESCRIPTION, COST_CODE, COST_CODE_ID, TRAFFIC_COLOR, CLASSIFICATION, STATUS, COST_ESTIMATE, LINE_ITEM_MARKUP, COMMITTED_COSTS, INVOICED_AMOUNTS, ACTUAL, RATE, RATE_QTY, LINE_ITEM_MARKUP_TYPE, FIVE_COLUMN_EQUIPMENT, FIVE_COLUMN_LABOR, FIVE_COLUMN_MATERIAL, FIVE_COLUMN_OTHER, FIVE_COLUMN_SUB, UNIT_NAME, UNIT, ADJUSTMENT, BID_NOTES, NOTES_TEAMLINK, NOTES_BID, FIELD_NOTES, NOTES_CLIENTLINK, NOTES_FIELD, GENERAL_NOTES, NOTES_GENERAL, ITEMS
    - ITEMS: array
      - 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": "03 - Concrete",
   "COST_CODE_ID": 10,
   "DESCRIPTION": "Cast in place concrete",
   "BID_NOTES": "Excludes rebar supply",
   "GENERAL_NOTES": "Pump truck required",
   "SUBCATS": [
       {
           "NAME": "Footings",
           "COST_CODE_ID": 10,
           "UNIT_NAME": "CY",
           "QTY": 160,
           "UNIT_COST": 87.5,
           "ITEMS": [
           {
             "NAME": "Footing concrete - place",
             "COST_CODE": 3011,
             "CLASSIFICATION": 3,
             "QTY": 120,
             "UNIT_COST": 85,
             "GENERAL_NOTES": "120 CY placed"
           }
         ]
       }
   ]
}

Example requests in cURL, C#, Python, and JavaScript can be found below:

cURL

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

curl -X POST https://api.constructiononline.com/api/EstimateCategories?estimateID={estimateID} -u {email}:{password} -H 'APIKey:{apikey}'

/* replace {username} with the email address for your ConstructionOnline account
           {password} with your ConstructionOnline password
           {apikey} with your provided API key 
           {estimateID} with the associated estimate'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/EstimateCategories?estimateID={estimateID}");

Python

#replace {username} with the email address for your ConstructionOnline account
#{password} with your ConstructionOnline password
#{apikey} with your provided API key
#{estimateID} with the associated estimate'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/EstimateCategories?estimateID={estimateID}"))

JavaScript

/* replace {username} with the email address for your ConstructionOnline account
           {password} with your ConstructionOnline password
           {apikey} with your provided API key 
           {estimateID} with the associated estimate'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/EstimateCategories?estimateID={estimateID}");

Responses

200: Success

A successful request will return a 200 response with a record of the newly created estimate category 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

Create an Estimate Category

Add a new estimate category to an existing project estimate in your ConstructionOnline company account

Requests

Responses