ErrLog.IO API

Webhook API

ErrLog.IO supports manual submission of errors via a Webhook. This can be used from a variety of languages, with example usage below.

Overview

To use this API, simply create a JSON object and send it via a POST to our our Webhook endpoint.

All objects (apart from your apikey) are dynamically typed, meaning you can include objects of any type, and from any language or platform, without having to specifically provide a strongly typed value.

Webhook Endpoint:

https://relay.errlog.io/api/v1/log

Examples

Note: In the example below we've used Newtonsoft.Json to serialize an object into a JSON string.

try {
    Console.WriteLine("We're going to throw an exception.");

    string result = null;
    string upper = result.ToUpper();
} catch (Exception ex) {
    StackTrace st = new StackTrace(ex, true);

    var obj = new {
        message = "This is a test message",
        apikey = "[Your-api-key]",
        applicationname = "Test Application",
        type = ex.GetType().ToString(),
        environment = Environment.GetEnvironmentVariables(),
        errordate = DateTime.Now,
        trace = ex.StackTrace,
        filename = st.GetFrame(0).GetFileName(),
        method = st.GetFrame(0).GetMethod().Name,
        lineno = st.GetFrame(0).GetFileLineNumber(),
        colno = st.GetFrame(0).GetFileColumnNumber(),
    };

    StringContent content = new StringContent(JsonConvert.SerializeObject(obj), 
                            Encoding.UTF8, "application/json");

    HttpClient client = new HttpClient();

    // You can capture the response if you are expecting a result. 
    // Most of the time this will be "OK" but could also be "Missing API Key", etc.
    string apiUrl = "https://relay.errlog.io/api/v1/log";
    HttpContent response = client.PostAsync(apiUrl, content).Result.Content;
    string result = response.ReadAsStringAsync().Result;
}

Note: In the example below we've used Newtonsoft.Json to serialize an object into a JSON string.

Try
    Console.WriteLine("We're going to throw an exceptiont.")

    Dim result As String = Nothing
    Dim upper As String = result.ToUpper()
Catch ex As Exception
    Dim st As New StackTrace(ex, True)

    Dim obj = New With { _
        Key .message = "This is a test message", _
        Key .apikey = "[Your-api-key]", _
        Key .applicationname = "Test Application", _
        Key .type = ex.[GetType]().ToString(), _
        Key .environment = Environment.GetEnvironmentVariables(), _
        Key .errordate = DateTime.Now, _
        Key .trace = ex.StackTrace, _
        Key .filename = st.GetFrame(0).GetFileName(), _
        Key .method = st.GetFrame(0).GetMethod().Name, _
        Key .lineno = st.GetFrame(0).GetFileLineNumber(), _
        Key .colno = st.GetFrame(0).GetFileColumnNumber() _
    }

    Dim content As New StringContent(JsonConvert.SerializeObject(obj), Encoding.UTF8, "application/json")

    Dim client As New HttpClient()

    ' You can capture the response if you are expecting a result. 
    ' Most of the time this will be "OK" but could also be "Missing API Key", etc.
    Dim apiUrl as string = "https://relay.errlog.io/api/v1/log";
    Dim response As HttpContent = client.PostAsync(apiUrl, content).Result.Content
    Dim result As String = response.ReadAsStringAsync().Result
End Try

curl -H "Content-Type: application/json" http://relay.errlog.io/api/v1/log 
-d '{ "message": "This is a test message from a Sample Project", 
"apikey": "[Your-api-key]", "applicationname": "SampleProject", 
"type": "System.NullReferenceException", "errordate": "2018-10-23 10:47:17 "}'

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.net.ssl.HttpsURLConnection;

public class ErrLogSample {
    public static void main(String[] args) throws Exception {
        System.out.println("About to create an exception that will be sent to ErrLog.IO..");

        try {
            String str = null;

            System.out.println(str.toUpperCase());
        } catch (Exception ex) {
            // Set up some variables
            Date now = new Date();
            String message = ex.getMessage();
            String stackTrace = ex.toString();
            StackTraceElement ste = ex.getStackTrace()[0];
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String formattedDate = df.format(now);
            String apikey = "[Your-api-key]";

            String postString =  
            "{" + 
                "\"apikey\": \"" + apikey + "\",\n" +
                "\"message\": \"" + message + "\",\n" +
                "\"errordate\": \"" + formattedDate + "\",\n" +
                "\"applicationname\": \"Java Sample\",\n" + 
                "\"trace\": \"" + stackTrace + "\",\n"                        +
                "\"method\": \"" + ste.getMethodName() + "\",\n" + 
                "\"lineno\":  "+ ste.getLineNumber() + "\n" + 
            "}";

            System.out.println(postString);
            URL url = new URL("https://relay.errlog.io/api/v1/log");

            byte[] postData = postString.getBytes(StandardCharsets.UTF_8);
            int postDataLength = postData.length;

            HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();

            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("User-Agent", "Java Test Application");
            conn.setRequestProperty("Content-Length", Integer.toString(postDataLength));

            DataOutputStream os = new DataOutputStream(conn.getOutputStream());

            os.write(postData);

            int responseCode = conn.getResponseCode();
            String responseMessage = conn.getResponseMessage();

            System.out.println("");
            System.out.println("ResponseCode: " + responseCode);
            System.out.println("Message: " + responseMessage);

            os.flush();
            os.close();
        }
    }
}

Note: This code relies on having the LWP modules installed. See http://search.cpan.org/dist/libwww-perl/lib/LWP.pm for more info.

use LWP::UserAgent;
my $ua = LWP::UserAgent->new;
my $server_endpoint = "https://relay.errlog.io/api/v1/log";

my $req = HTTP::Request->new(POST => $server_endpoint);
$req->header('content-type' => 'application/json');
            
my $post_data = "
    {\"apikey\": "[Your-api-key]\",
    \"message\": \"null\",
    \"errordate\": \"2025-07-12 20:21:23\",
    \"applicationname\": \"Perl Sample\",
    \"trace\": \"The function I'm in\",
    \"method\": \"main\",
    \"lineno\":  19
}";

$req->content($post_data);
            
my $resp = $ua->request($req);
if ($resp->is_success) {
    my $message = $resp->decoded_content;
    print "Received reply: $message\n";
}
else {
    print "HTTP code: ", $resp->code, "\n";
    print "HTTP message: ", $resp->message, "\n";
}

Variable	Type	Required	Description
apikey	string	required	This is your ErrLog.IO apikey.
message	dynamic	required	This is the error message that you want logged.
type	dynamic	recommended	This is the type of event you're logging. In C# it could be "NullReferenceException", "ArgumentException" or just "Exception".
applicationname	dynamic	recommended	This is the name of the application that caused the event. Helpful for distinguishing different applications.
errordate	dynamic	optional	The datetime the event occurred. Should be in the format yyyy-mm-dd hh:mm:ss where specified.
querystring	dynamic	optional	The querystring of the request which caused the event.
trace	dynamic	optional	This is the stacktrace of the exception.
page	dynamic	optional	This is the page in which the event occurred
method	dynamic	optional	This is the method in which the event occurred
lineno	int	optional	The line number of the code which caused the event.
colno	int	optional	The column number of the code which caused the event.
filename	dynamic	optional	The filename of the code which caused the event.
useragent	dynamic	optional	This is the useragent string for the client's browser
browsername	dynamic	optional	This is the browser the client was using when the event occurred.
servername	dynamic	optional	This is an identifier for the server/device on which the event occurred.
browser_capabilities	dynamic	optional	This is identifies the capabilities of the client's browser
ipaddress	dynamic	optional	This is the IP address of the client device.
custom	dynamic	optional	This can be used to store any additional data you want.
language	dynamic	optional	This is the programming language the code was written in.
session_data	dynamic	optional	Represents a HttpSessionState object.
assemblyversion	dynamic	optional	You can use this to represent the version of your application/library.
application_data	dynamic	optional	Used to store name/value data from your Application state.
request_header	dynamic	optional	This is used to store the HTTP Request Headers as name/value pairs.
request_formdata	dynamic	optional	This is used to store the HTTP Request Form Data as name/value pairs.
request_cookies	dynamic	optional	This is used to store the HTTP Cookies as name/value pairs.
environment	dynamic	optional	This is used to store general environment metrics as name/value pairs.

The Webhook API will return a plain-english error message describing any issues it encounters when you POST an error to it.

Missing API Key	The API key is a mandatory field and required for the API to correctly function.
Incorrect usage of Webhook	A HTTP POST is the method used to send data to the Webhook. GET and other HTTP methods are not supported.

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