https://api.constructiononline.com/api/Invoices?id={id}&Info={invoiceInfo}
This endpoint allows users to edit an existing invoice within their ConstructionOnline company account. To update an invoice, users need the unique numerical ID associated with it, stored in the "ID" property. Updated properties should be specified in the request's "invoiceInfo" parameter; only the properties listed here will be modified, while all others remain unchanged.
To update an invoice item, users also need the unique numerical ID assigned to that specific item.
Requests
id: integer
- Unique identifier for the invoice.
Info: JSON
- Updated properties for the invoice.
- Allowed properties for the invoice: TITLE, INV_DATE, STATUS, COM_PRORATED, PAID_AMOUNT, NOTES, DUE_DATE, CLIENT_ID, TERM_ID, ITEMS
- Allowed properties for the purchase order ITEMS: NAME, DESCRIPTION, TOTAL, RETAINAGE, MARGIN, QTY, RATE, TAX_TYPE, TAX_PERCENT, MARKUP_TYPE, MARKUP
Sample request URL:
- https://api.constructiononline.com/api/Invoices?id=67540&info={"TITLE" : "Mechanical Sub Invoice", INV_DATE" : "2026-07-20T00:00:00", "ITEMS" : [{"ID" : 461592, "NAME" : "LABOR", "QTY" : 50.0}]}
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
# {id} with the purchase order's ID
# {invoiceInfo} with the updated properties
curl -X PUT https://api.constructiononline.com/api/Invoices?id={id}&Info={invoiceInfo} -u {email}:{password} -H 'APIKey:{apikey}'
C#
/* replace {username} with the email address for your ConstructionOnline account
{password} with your ConstructionOnline password
{apikey} with your provided API key
{id} with the purchase order's ID
{invoiceInfo} with the updated properties */
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.PutAsync(endpoint, content).Result.ToString();
}
return response;
}
MakeRequest("api/Invoices?id={id}&Info={invoiceInfo}");
Python
#replace {username} with the email address for your ConstructionOnline account
#{password} with your ConstructionOnline password
#{apikey} with your provided API key
#{id} with the purchase order's ID
#{invoiceInfo} with the updated properties
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("PUT", url, headers=headers, data=payload)
return json.dumps(json.loads(response.text), indent=2)
#Main Program
print(makeRequest("api/Invoices?id={id}&Info={invoiceInfo}"))
JavaScript
/* replace {username} with the email address for your ConstructionOnline account
{password} with your ConstructionOnline password
{apikey} with your provided API key
{id} with the purchase order's ID
{invoiceInfo} with the updated properties */
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: 'PUT',
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/Invoices?id={id}&Info={invoiceInfo}");
Responses
200: Success
A successful request will return a 200 response with a record of the edited invoice 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. The ID may have been entered incorrectly or an invoice with the entered ID does not exist.
409: Error
The invoice was unable to be edited since there are existing payments that have been recorded against the original invoice.
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: July 22, 2026