elmah.io

Mocking HttpClient requests for C# unit tests

Learn how to mock requests made through a HttpClient in C#. Unit testing code that makes external requests is easy using this simple approach.

"Secret" elmah.io features #2 - Correlate messages from apps

In the second post in the series about "secret" elmah.io features I want to present you for correlations. Learn how to batch messages together.

Testing logging code with Microsoft.Extensions.Logging and FakeLogger

This post will introduce you to FakeLogger and how it can be used to test logging code when using Microsoft.Extensions.Logging and ILogger.

"Secret" elmah.io features #1 - Include source code in errors

This new series dives into those not-so-commonly-known elmah.io features. In the first post, you will learn how to include source code on errors.

Validate NuGet packages before publishing from GitHub Actions

Using a couple of available tools you can validate NuGet packages before publishing to nuget.org. Learn how to set it up on GitHub Actions.

Dependency Injection using keyed services is finally in ASP.NET

Learn how to inject dependencies using keys in ASP.NET Core. With keyed services you can finally inject multiple objects of the same type.

Validate JSON files against schema in Azure DevOps build

This post will show how to validate JSON files against a JSON Schema as part of a build on Azure DevOps. Never push invalid JSON files again.

Setting up better logging in Azure Functions

Learn about how to set up logging in Azure Functions. With just a few changes, it is easy to improve on what comes from the new project template.

Conditionally add middleware in ASP.NET Core

Learn how to set up middleware in ASP.NET Core based on one or more conditions. This can help you run custom code for only specific endpoints.

How to force reload cached JSON Schemas in Visual Studio

Visual Studio caches JSON Schema files used for IntelliSense. Learn how to force reload a schema if Visual Studio doesn't pick up the changes.

How to modify response headers in ASP.NET Core middleware

Learn how to modify response headers from ASP.NET Core middleware. You need to use the correct hook to avoid a System.InvalidOperationException.

Creating custom debug visualizers for Visual Studio 2022

Learn how to create a debug visualizer for Visual Studio. In this post, I'll develop a visualizer of email addresses to help you get started.

9 "hidden" features in Visual Studio that you may not know

In this post, I'll share a list of features that some of you may not know. From small gems to large features that you probably haven't seen.

Parsing websites in C# with Html Agility Pack or AngleSharp

Learn how to parse a website from .NET/C# using the two most popular NuGet packages for the job: Html Agility Pack and AngleSharp.

Building and deploying AWS email templates with Azure DevOps

Learn how to build MJML/Handlebars.js email templates with Gulp on Azure DevOps. Prepare the templates for uploading om AWS Simple Email Service.

Building MJML email templates with Gulp

Learn how to build MJML email templates with Gulp. In this post, we'll prepare an email template ready to upload on AWS Simple Email Service.

Creating AWS email templates with Handlebars.js and MJML

Learn how to create email templates with Handlebars.js and MJML. Handlebars is used to insert dynamic content while MJML is for building HTML.

Normalize and compare URLs with C#

This post will show you how to simplify URLs to better compare them and to implement uniqueness checks across URLs with multiple parameters.

How to get the client IP in ASP.NET Core even behind a proxy

This post will explain how to get the IP of the requesting client in a proxied ASP.NET Core website. Learn all about custom headers and more.

Turn a Hue light red when website is down with IFTTT & elmah.io

Learn how to use IFTTT and elmah.io to turn your Philips Hue light red when your website is down, ensuring you never miss a critical alert!

Deploy Access Restricted Azure website from DevOps Pipelines

Deploy access restricted Azure websites from DevOps pipelines easily with this step-by-step guide to enhance your website's security.

Creating Visual Studio extensions using Roslyn analyzers

Learn how to develop Visual Studio extensions with ease using Roslyn analyzers. This step-by-step guide will help you get started in no time!

Creating and downloading zip files with ASP.NET Core

Learn how to zip a list of files and download it from an ASP.NET Core website. The post also digs down into a couple of best practices.

Logging and global error handling in .NET 7 WPF applications

Set up logging with Microsoft.Extensions.Logging in WPF applications running on .NET 7. Learn how to configure global error handling and logging.

Build and publish Visual Studio extensions with GitHub Actions

Set up automated builds of Visual Studio extensions. Read through, to learn how to use GitHub Actions to pick up commits and publish extensions.

Polling asynchronous APIs with Azure Durable Functions

Learn about polling an asynchronous API with Azure Durable Functions. Easily integrate with async REST APIs using an initial request and retries.

Best Chrome extensions for web developers

A list of the best Chrome extensions for web developers. Read on to see all of the extensions we use while developing the websites for elmah.io.

How to generate header images for blogs and ASP.NET Core

Learn how to generate header images using Bannerbear. The post also highlights how images can be generated using ASP.NET Core middleware.

Built-in rate limiting in ASP.NET Core vs AspNetCoreRateLimit

Learn about the built-in rate-limiting middleware in ASP.NET Core. The post uses limiting on an API key and compares it to AspNetCoreRateLimit.

How to download files from ASP.NET Core MVC

A blog post about how to implement file download in ASP.NET Core (MVC). Learn about the built-in result object types and when to use which type.

How to get base URL in ASP.NET Core

Learn how to get the base path (schema, domain, and port) in an ASP.NET Core application. Examples for both MVC and Razor Pages are included.

Three NuGet packages to improve exceptions in .NET/C#

In this post, I'll introduce you to three different NuGet packages that will help you when dealing with exceptions in .NET/C#.

elmah.io launches two GitHub Actions in the GitHub Marketplace

Announcing elmah.io as a GitHub Technology Partner. Learn about the GitHub app as well as two build steps that integrate Actions with elmah.io.

Building a quick Reddit Blazor client without Reddit's API

Learn how to build a simple Reddit client with Blazor and the pushshift.io API. Pull conversations and statistics from Reddit with a few lines.

The Repository Pattern is simple yet misunderstood

This post revisits the Repository Pattern, addresses the implementation pitfalls in .NET, and reviews proposed solutions to reduce complexity.

Deploying a MkDocs documentation site with GitHub Actions

Automatically deploy a documentation site, built with MkDocs, using GitHub Actions. Also, learn how to automate tasks like minifying JS and CSS.

Hosting a MkDocs-driven documentation site on GitHub Pages

Learn about how to host a documentation site implemented with MkDocs and Markdown on GitHub Pages. Easily deploy the static website for free.

Creating a documentation site with MkDocs

Learn how to create a documentation site for your product using MkDocs. MkDocs is a static website generator running on Python and Markdown.

Building a Stack Overflow browser as a VS extension

Learn how to integrate with the Stack Overflow API from C#. In this post, I'll build a Visual Studio extension that shows SO results within VS.

ASP.NET Core 7 has built-in dark mode for error pages

ASP.NET Core 7 comes with dark mode for the developer exception page built-in. Learn about how it works and how to enable it on Windows here.

Search videos through the YouTube Data API from C#

Integrating with YouTube from C# is easy using the Google.Apis.YouTube.v3 NuGet package and a little help. Learn how we have integrated here.

How to integrate with the Trello API from .NET/C#

There are no Trello NuGet packages and Trello's documentation lacks .NET examples. In this post, I'll show you what I learned while integrating.

Collect and track Lighthouse results with elmah.io

Automatically collect Lighthouse results with elmah.io Uptime Monitoring. Get a history of scores like SEO, performance, and best practices.

Download, parse, and store SSL certificates in C#

Learn about how to download, parse, and store SSL certificates in C#. Parse common names and present detailed certificate information like a pro.

Introducing the Dark Screen of Death

Ever experienced being blinded during late-hour work by the developer exception page in ASP.NET Core? Install the Dark Screen of Death extension.

Bulk download from Azure Blob Storage with C#

A quick example of how to easily download multiple blobs in bulk from Azure Blob Storage using the Azure.Storage.Blobs NuGet package.

Added 5 new sponsorships to the batch

We are fans of sponsoring people working on open-source libraries we use on elmah.io. Here's a quick update on the recent 5 members in the batch.

Test run of HTTP Logging in ASP.NET Core 6

In this post, I'll introduce you to the new HTTP Logging middleware available in ASP.NET Core 6. Learn how to set it up and how to configure it.

Server-side source map support on elmah.io

With elmah.io's server-side source map support, we automatically try to de-minify JavaScript stack traces. Get a quick introduction in this post.

3 new free tools for .NET developers

We have developed three new free tools for .NET developers: Appsettings.json Transform Tester, Base64 Image Encoder, and MD5 Encoder.

Updating NuGet packages from command-line - deep dive

I set out to find a better way to update NuGet packages across multiple projects and solutions. This post is a summary of the things I learned.

Ahead-Of-Time Compilation for Blazor Wasm

In this article, we will look at how you can compile your code directly to Wasm Ahead-Of-Time (AOT) and what pros and cons this brings.

Async processing of long-running tasks in ASP.NET Core

In this post, I'll show you how to implement async processing in ASP.NET Core, using a queue and the Background Worker feature.

Debugging System.FormatException when launching ASP.NET Core

This post contains a list of possible causes of a System.FormatException being thrown while launching an ASP.NET Core website and how to fix it.

Stream large content from ASP.NET Core to avoid OutOfMemoryException

Learn how to stream a large response from an ASP .NET Core web application to the browser without the risk of throwing an OutOfMemoryException.

Embedding source code on errors logged to elmah.io

Learn about the Embedded source code feature. Bundle the failing source code as part of errors to avoid checking out code and launching the IDE.

HTTP Error 500.30 - ASP.NET Core app failed to start help

In this article, I'll guide you through problems during the startup of an ASP.NET Core project. Get help where to look and possible solutions.

Logging in Unity

In this article, we will see how you can enable logging for unhandled exceptions and debug messages in a Unity application.

How to authorize and post Slack messages from ASP.NET Core 💬

This post will show you how to let a user authorize their Slack workspace, select a channel, and post messages to that channel from ASP.NET Core.

Upload and resize an image natively with ASP.NET Core 🖼️

With this post, I want to show a simple approach for uploading and resizing images with ASP.NET Core that doesn't require any external libraries.

Show a name and profile photo with .NET and Gravatar 🤵

Don't have a user profile photo or do you want a fallback before one is uploaded? In this post I'll show you how to use Gravatar to achieve both.

Introducing Breadcrumbs

We're happy to announce the introduction of Breadcrumbs on elmah.io. This post will introduce you to Breadcrumbs and how to implement it.

New LINQ extensions in .NET 6 and benchmarks

This post will go through the new LINQ extensions made available in .NET 6. Learn about MaxBy, DistinctBy, FirstOrDefault with default values, and more.

Create a colored CLI with System.CommandLine and Spectre 🎨

This post will introduce the System.CommandLine and Spectre.Console packages. Follow the tutorial to learn how to build a CLI with commands and colors.

Using the new PriorityQueue from .NET 6

.NET 6 has brought along a lot of new features. This post will show how to use a PriorityQueue in practice by solving a problem from open.Kattis.com.

Adding CAPTCHA on form posts with ASP.NET Core 🚦

We all tried to solve CAPTCHASs. In this post, I'll introduce you to CAPTCHAs and show you how to add one in ASP.NET Core using the reCAPTCHA service.

Pretty print/syntax highlight .NET stack traces in a browser ✨

Want to print stack traces on your website? In this post, I'll show you how to pretty print and syntax highlight .NET stack traces directly in the browser.

Rendering dynamic content in Blazor Wasm using DynamicComponent

In this article, we'll see how to use the new DynamicComponent from .NET 6 to render dynamic content and to avoid tight coupling between page and component.

Subscribe users to a Mailchimp newsletter from .NET/C# 📧🐵

Learn how to subscribe emails to a Mailchimp newsletter from C#. This post will demonstrate how to do it using a signup form on an ASP.NET Core website.

Blazor WASM 404 error and fix for GitHub Pages

In this article we will look at the 404 error that often occurs when accessing a route directly on a GitHub Pages hosted Blazor WASM page and how to fix it.

Easy generation of fake/dummy data in C# with Faker.Net

Faker.Net can help to generate a lot of random names, addresses, emails, etc. In this article, we will show the range of possible values it can create.

We are looking into GitHub Sponsors (and you should too)

With GitHub Sponsors, we now have a great way to gather all sponsorships in one place. Here's a list of the first five people we decided to sponsor and why.

Avoid password reuse with Pwned Passwords and ASP.NET Core

In this post, I'll show you how we are avoiding people to re-use pwned passwords on elmah.io in our ASP.NET Core web app using the Pwned.Passwords package.

6 free tools for .NET developers

elmah.io provides several free tools for .NET developers. From the web.config validator to a JSON formatted, we are here to help you with your daily tasks.

How to map IPs to country for free with .NET and IP2Location

In this post, we will show you how to map IP addresses to locations for free using .NET and IP2Location. Enrich your data with country information and more.

Introducing support for Xamarin

Logging errors from mobile applications developed in Xamarin and Xamarin.Forms are now as easy as you know it from the web world.

Generate iCal calendar with .NET using iCAL.NET

In this article, we will show how you can serve an endpoint in the iCal format for .NET with ease using the package iCal.NET.

How to implement two-factor authentication in ASP.NET Core

Supporting two-factor authentication (2FA) in your web app is important in most cases. In this post, I'll show you how we did it on elmah.io.

Export data from Google Analytics with .NET

Learn how to export data from Google Analytics using Google's official Google.Apis.AnalyticsReporting.V4 NuGet package.

Rate limiting API requests with ASP.NET Core and AspNetCoreRateLimit

In this post, I'll teach you how to handle a large number of requests to an ASP.NET Core application by rate-limiting with the AspNetCoreRateLimit package.

Using JS Object References in Blazor WASM to wrap JS libraries

In this article, we will show what IJSObjectReference is and how it can be used for so much more than just JavaScript isolation.

The NuGet packages we use to build elmah.io

Get inspired by this list of NuGet packages we use to build elmah.io. Learn about each package, how we use it, and what we like about it.

How to fix Blazor WASM base path problems

This post will show you how to fix a common problem when setting the application base path with Blazor WebAssembly.

Building and testing on multiple .NET versions with GitHub Actions

Learn how to build and test a .NET (Core) application on multiple versions of .NET with GitHub Actions.

Major updates to elmah.io Uptime Monitoring

While we usually describe all noticeable changes on the elmah.io Changelog, I want to dedicate a blog post for some major updates that we just released to elmah.io Uptime Monitoring. Configurable regionsA request that we often get is the possibility of configuring which regions that should ping your

HTTP Error 500.19 - The requested page cannot be accessed

The HTTP Error 500.19 can be a frustrating error to resolve when hosting on IIS. In this post, I'll show you the most common causes of the error.

How to add User-Agent header to HttpClient in .NET

This article will introduce you to the format for the User-Agent HTTP header as well as how to add it in various ways when using HttpClient in .NET/C#.

Predicting Die Hard fans with ML.NET and C#

This post will teach you how to predict the value of a boolean using ML.NET and a binary classification trainer. The code uses movie scores as an example.

Monitoring Windows Services implemented in .NET

Learn to monitor Windows Services. Windows comes with a set of tools that help monitor services. The post also introduce Perfmon for performance.

Managing bounced emails with AWS SES and Azure Functions

This post will show you how to implement a local list of bounced emails with AWS Simple Email Service (SES) and Azure Functions.

Monitoring .NET scheduled tasks - Tools and alternatives

There's a lot of possibilities when it comes to developing scheduled tasks with .NET. This post is an overall guide to monitoring scheduled tasks.

Call anonymous C# functions from JS in Blazor WASM

In this article, we will look at how we can call C# functions from a JS library in Blazor WASM. This can be useful to integrate with existing JS libraries that react to different events. This article is a continuation of a project made in our other article Wrapping JavaScript

How to send push notifications to a browser in ASP.NET Core

In this article, we will show how you can subscribe to Push Notifications using ASP.NET Core and how you can send Push Notifications from .NET as well.

How we do bundling and minification in ASP.NET Core

Learn about how we have implemented bundling and minification in ASP.NET Core with the help of bundleconfig.json, the BundlerMinifier package, and gulp.

Error monitoring and detailed logging of an ASP.NET Core application with PostSharp and elmah.io

In this article, we show how to add error monitoring and detailed logging to an ASP.NET Core application with PostSharp Logging, Serilog, and elmah.io.

Audit .NET/.NET Core Apps with Audit.NET and AWS QLDB

Get an introduction to monitoring .NET and .NET Core applications with the auditing framework Audit.NET and AWS Quantum Ledger Database (QLDB).

Moq vs NSubstitute vs FakeItEasy - Which one to choose?

This article will introduce you to the three major mocking frameworks for .NET: NSubstitute, Moq, and FakeItEasy. Get help deciding which one to choose.

Wrapping JavaScript libraries in Blazor WebAssembly/WASM

In this article, we will show how you can wrap a JavaScript library in Blazor and thereby getting that one feature into Blazor WebAssembly.

Facebook and LinkedIn groups for .NET developers

Get an overview of the best Facebook and LinkedIn groups to be a part of. Stay updated on new blog posts and ask questions or help other .NET developers.

Lessons learned after migrating 25+ projects to .NET Core

In this post I'll share some of the lessons learned migrating elmah.io's 25 Azure Function apps and 5 web apps to ASP.NET Core.

Add Razor runtime compilation when developing ASP.NET Core

Learn how to update Razor files with ASP.NET Core without having to compile and restart the project. This post will go through the multiple ways possible.

How to secure ASP.NET Core with OAuth and JSON Web Tokens

Learn about how to secure your ASP.NET Core APIs with OAuth 2.0 and JSON Web Tokens without using third-party services like IdentityServer, Okta, and Auth0.

Split IP and port in JavaScript with regular expressions

Learn how to split a string with both an IP address and a port number in JavaScript using regular expressions. Most scripts out there don't handle ports.

Get a 40% discount on Manning books and other good deals

I just want to quickly mention an offering we have called the elmah.io Goodiebag. The goodiebag is a range of discounts for popular software products, books, conferences, and other development related items. The discounts are available for elmah.io users on the Business plan and up. Recently, new deals

.NET/C# newsletters to subscribe to - Keep up with the news

Get news about .NET, C#, ASP.NET Core, and much more directly in your inbox. With this list of the ultimate newsletters you will never miss important news.

New Zapier integration

We have re-built our integration with Zapier. In case you don't know Zapier it's an awesome product connecting more than 2,000 online services with a few clicks of a mouse. If you have used the old app, you will know that it didn't exactly follow the high quality of

Implementing always signed in with ASP.NET Core and Azure

Learn about how to implement an always signed in/never sign out feature with ASP.NET Core. Also covers enabling data protection when hosting on Azure.

Save money on Azure with cost analysis and free tools

Learn about how to reduce your Azure costs by analyzing and optimizing how to use resources. Get best practices and introduction to the available programs.

Top 10 books every .NET/C# developer should read

Check out my top 10 list of books that I have either enjoyed reading myself or got recommended by developers friends and plan to read.

Access ASP.NET Core website hosted on IIS Express from a phone

Learn about how to access an ASP.NET Core website, hosted in IIS Express on localhost, from a phone or other device on your local network.

Cookie authentication with social providers in ASP.NET Core

Show you how to create an authenticated website with ASP.NET Core based on a secure cookie, supporting username/password as well as social providers.

Introducing Heartbeats

Time for some exciting news from your friends at elmah.io. Introducing elmah.io Heartbeats. We don't just want to be your go-to tool when needing to monitor web applications. All companies use a combination of tools and frameworks to create business value for their customers. Windows services, Scheduled tasks,

Export data to Excel with ASP.NET Core

In this post I'm sharing my experiences with generating Excel files from ASP.NET Core. The post includes examples of generating both CSV and XLSX files.

Extending the date for removing the v2 API

Due to the current health situation, we have decided to extend the period where the old v2 API will be supported. The v2 API will be removed on June 1th 2020. We have created this guide for upgrading from v2 to v3: https://docs.elmah.io/upgrade-elmah-io-from-v2-to-v3/ To make it

NLog Tutorial - The essential guide for logging from C#

The ultimate tutorial for NLog. Learn about everything from logging and structured log messages to layout renderers and configuration of common targets.

Cross-site request forgery (CSRF) with ASP.NET Core and AJAX

Learn how to configure Cross-site request forgery (CSRF) checks when using AJAX with jQuery or similar in an ASP.NET Core web application.

Upload and resize an image with ASP.NET Core and ImageSharp

Learn how to use ImageSharp and ASP.NET Core to let users upload images and resize them. ImageSharp is a great replacement for the WebImage class in ASP.NET

The ASP.NET Core security headers guide

The ultimate guide to adding security headers in ASP.NET Core. Some features are built-in to core using middleware while others require manual work.

ASP.NET Core middleware with Roslyn Analyzers - Part 2

Learn how to create a Roslyn analyzer that helps your users insert middleware in the Configure method of the Startup.cs file and in the right order.

Generate a PDF from ASP.NET Core for free

Show you how to generate a PDF file from ASP.NET for free. There are a lot of paid components out there, but it doesn't have to cost you anything.

ASP.NET Core middleware with Roslyn Analyzers - Part 1

Learn how to create Roslyn Analyzers to help add ASP.NET Core middleware and in the right order.

How to send emails from C#/.NET - The definitive tutorial

The ultimate guide to sending emails from C# based on our experiences with the built-in SMTP library in .NET, AWS Simple Email Service, Mandrill, and Azure.

C# how to convert a string to int

Get all the details about how to convert a string to int with C#. Learn how to handle exceptions and all of the worst practices that everyone is doing.

Publish a self-contained .NET Core 3.1 app on Azure DevOps

Tutorial to build and publish a console application including the .NET Core framework from Azure DevOps Pipelines.

Paid subscriptions with ASP.NET Core and Stripe Billing

Setting up reccurring payments from ASP.NET Core is easy with Stripe Billing. Read about how to use Stripe.js and the .NET client to create subscriptions.

ASP.NET Core request logging middleware

Simple example of how to implement request logging using Microsoft.Extensions.Logging and ASP.NET Core middleware. Plus things to be aware of during config.

Effective Error Logging in Windows Forms Applications with C#

Error logging is an essential part of any application. Learn how to implement effective error logging in C#-based Windows Forms applications.

The ultimate guide to secure cookies with web.config in .NET

How to secure your cookies in ASP.NET and MVC, using Secure and HttpOnly attributes. Also learn about Cross-site tracing and Cross-site request forgery.

Find anomalies with spike detection and ML.NET

A real-life example of how to find anomalies in time-series data using spike detection available in ML.NET. Learn how to utilize the Microsoft.ML package.

Debugging System.NullReferenceException - Object reference not set to an instance of an object

Get help debugging System.NullReferenceException. The post will teach common solutions for both identifying and fixing causes of a NullReferenceException.

Common exceptions and fixes in Entity Framework and SQL Server

In this article, we will go through some of the most common errors and some of the possible ways these errors could be fixed.

How to write to a file with C# in 2019 - StackOverflow doesn't get it right

.NET offers an extended set of APIs to write content to a file. In this post I will list and compare the possibilities, showing you the best ways in 2019.

How to write to a file with C# - StackOverflow doesn't get it right

.NET offers an extended set of APIs to write content to a file. In this post I will list and compare the possibilities, showing you the best ways in 2019.

C# exception handling best practices

Five best practices that will make you an absolute pro when working with exceptions. Make sure not to make these common mistakes when writing C#.

Fix max URL and query string length with web.config and IIS

Learn how to configure IIS to allow both long URLs as well as long query strings. Without it, your web server may return 404s to your users.

OAuth authentication with Facebook and ASP.NET Core

The aim of this post is to teach you how to implement Identity Authentication & Authorization with OAuth, Facebook and ASP.NET Core 3.0.

OAuth authentication with Facebook and ASP.NET Core 3.0

The aim of this post is to teach you how to implement Identity Authentication & Authorization with OAuth, Facebook and ASP.NET Core 3.0.

Convert images to WebP with ASP.NET Core - Better than png/jpg files?

In this article, you will learn how to save bandwidth and convert png and jpg images to Google's WebP format using ImageProcessor and ASP.NET Core.

Partner with BrowserStack to support real-device debugging

we have partnered with BrowserStack to help you debug client-side errors on devices, browsers and operating systems that you don't currently own.

Migrating the elmah.io API to ASP.NET Core

We just launched a brand new version of our API. The big difference is that the API is now running on ASP.NET Core (instead of ASP.NET Web API).

Structured logging vNext

With the next level of support for structured logging, elmah.io now support searches for templated messages. You can even define rules based on templates.

Web.config location element demystified

Learn every detail about multiple Web.config files in the same project and how to utilize the location element to support per file/directory configuration.

The best Twitch and YouTube channels for .NET developers

A great way to learn the newest technology available in .NET is through live coding sessions. You can find a lot of streams on both Twitch and YouTube.

Web.config redirects with rewrite rules - https, www, and more

IIS rewrite rules is a powerful feature that enables redirect www to non-www, non-www to www, force HTTPS, and much more. This post will teach you how.

Instant errors on SMS from ASP.NET Core with Twilio and elmah.io

Learn how to obtain real-time SMS error messages using C#, ASP.NET and elmah.io.

Web.config transformations - The definitive syntax guide

The best tutorial for web.config/app.config transformations. Learn the syntax and how to test it. Included are also examples like replacing appSettings.

Debugging System.AccessViolationException - DllImport hell

Learn how to debug System.AccessViolationException when calling C++ code from C#, with unhandled errors in IIS modules and from the WebBrowser control.

Debugging System.AggregateException - even in async code

Learn everything about how to debug async errors in C# like: Exception thrown System.AggregateException in mscorlib.dll - a task was canceled.

The ultimate guide to connection strings in web.config

Learn everything there is to know about connection strings in web.config. From setting up SQL Server using Windows Authentication to password encryption.

log4net Tutorial - The Complete Guide for beginners and pros

In this tutorial I will tell you about logging in C#, how to create log4net configuration, explaining log levels, and examples with different appenders.

Debugging System.UnauthorizedAccessException (often followed by: Access to the path is denied)

Possible causes and fixes of the System.UnauthorizedAccessException. Continue reading to learn about IO errors when dealing with files or setting up IIS.

Web.config customErrors element with ASP.NET explained

Learn everything you need to know about showing custom error pages in ASP.NET and MVC using the customErrors element in your web.config file.

Issue Tracking 2.0

You may remember our quest to introduce light-weight issue tracking capabilities in elmah.io. If not, check out Mark errors as fixed, dashboards and more. Last week we silently launched the next chapter. Before I go into details about the new features, I want to put a few words on

Serilog vs log4net

Serilog and log4net are popular choices when choosing a logging framework in .NET. Read this guide to learn all about each framework and what to pick.

Accepting payments with Stripe and ASP.NET Core

Accepting payments through Stripe using ASP.NET Core is a perfect choice. Read through this post to get started fast and to learn about the pitfalls.

Debugging System.IO.FileNotFoundException - Cause and fix

FileNotFoundException isn't always as simple as it seems. Learn about the causes and fixes, including problems loading assemblies and IIS security issues.

Country support

Search errors by country, ignore 404s from a specific country and much more using country support on elmah.io.

Serilog vs NLog

It's hard picking between Serilog and NLog. Both awesome .NET logging frameworks with a rich feature set. Read through this post to make the decision.

elmah.io for Startups

Some of you may remember that we had a special program for Microsoft BizSpark members. Since Microsoft pulled the plug on that, we took some time reevaluating what to offer going forward. Today, we are ready to reveal our new program simply called elmah.io for Startups. As a member

ASP.NET Core (not that secret) User Secrets Explained

The best guide to using ASP.NET Core User Secrets. Helps you keep those connection strings out of course control and enables per-developer settings.

Debugging System.OutOfMemoryException using .NET tools

The complete guide to debugging System.OutOfMemoryException. In this post, I will show you how to use Perfmon and a profiler to track down slow methods.

Individual developer settings in ASP.NET Core

This post will show you how to utilize ASP.NET Core to specify individual settings per developer in your team, using appsettings and environment variables.

Comparing the top 6 .NET continuous integration build servers

A comparison between the top 6 most used continuous integration servers for building .NET projects. See the strengths and weaknesses of each product.

New Advisor at elmah.io: Kenneth Auchenberg

It's time for a new face here at elmah.io. We are continuously improving our advisory board (remember Simon and Peter?). Today, I want to introduce you to the recent addition: Meet Kenneth Auchenberg. Kenneth doesn't need much introduction since he is already a familiar face in the .NET community.

elmah.io User Survey 2018

The results from our 2018 user survey are in. Check out what our users think of elmah.io and where we can improve.

Publishing ASP.NET Core 2.2 health check results to elmah.io

By integrating ASPNET Core 2.2 health checks and elmah.io, you will be able to monitor when and why your website starts failings. Stop looking in log files.

9 awesome .NET conference talks you don't want to miss

Most conferences tape sessions and make them publicly available after the conference. This is a list of my favorite .NET, C# or Azure related talks.

Taking structured logging and elmah.io to the next level

Using structured data in modern logging frameworks, all fields on elmah.io can be filled. Supported by Serilog, NLog and Microsoft.Extensions.Logging.

ASP.NET Core Health Checks Explained

Get the full overview of how to implement health checks with ASP.NET Core 2.2. Health checks can help you monitor your websites and their dependencies.

Retry failed requests

Retry failed request lets you check if a failing endpoint has been fixed. By clicking a simple button, elmah.io recreates the request as when it failed.

Our favourite .NET, Azure and C# podcasts

A list of podcasts containing information about .NET, Azure, C# and related Microsoft technologies. Get introduced to the 8 podcasts we are listening to.

Introducing Client-side logging to elmah.io

We are ready to cover more platforms, by introducing client-side logging. Log all JavaScript errors happening in the user's browser to your elmah.io logs.

Continuous deployment to Azure from Azure DevOps

Tutorial on setting up continuous deployment from Azure DevOps to an Azure website. The post shows how to utilize DevOps Pipelines (release management).

The Daily Digest Email Reloaded

With the new Daily Digest Email, you'll get a much better overview of what happened. Progress indicators, and batch actions are among the new features.

API Key Permissions

API key permissions make sure that no one is able to call endpoints on the elmah.io API, that they aren't allowed to. Control both entities and methods.

JavaScript Error Handling

JavaScript error handling can be helpful to help debug code. Although we think we are good enough at programming sometimes we still face errors. These errors can occur due to inattention, not necessarily due to lack of knowledge, because of an erroneous server response or many other reasons for which

17+ Must Have .NET Developer Tools - The Essential List

Check out our list of favourite .NET development tools. You already know Visual Studio, but there's a range of good tools to help you be a better developer.

Deprecating the v2 API and what that means for you

The elmah.io API has seen three major iterations so far. Two years ago, we launched v3 in beta and last year, we moved the new version as well as all client integrations to stable. Time has come to deprecate the old v2 API. So what does that mean for

Debugging: System.Net.WebException - The remote name could not be resolved

The ultimate guide to handling System.Net.WebException: The remote name could not be resolved in C# and how to debug the exception using Ping and Nslookup.

Building a cloud editor with SignalR and ASP.NET Core

With the release of 2.1, we now have support for SignalR in ASP.NET Core. In this tutorial, we show you how to build a collaborative editor using SignalR.

New Advisor at elmah.io: Peter Terkildsen

We are currently building an advisory board (remember Simon?). Getting feedback from people longer down the path, is a great way to improve your product/business and enable some shortcuts. Today, I'm happy to introduce you to: Peter Terkildsen. Here's a few words from Peter: "Hi, I'm Peter. I

NLog vs log4net

NLog and log4net are popular logging frameworks for .NET. Both are implemented in C#, but there is a range of differences, shown to you in this post.

Web.config Validator

It's interesting how you sometimes build a feature, launch it, and people use it for something you didn't anticipated. This turned out to be the case with the ELMAH configuration validator that we launched two years ago. The idea was to be able to upload a Web.config file and

.NET Web Application Logging Essentials ebook

If you are a elmah.io newsletter subscriber, you may have heard about an ebook we are writing named .NET Web Application Logging Essentials. You know, the one with the Log Lady on the cover: I'm happy to report, that the ebook is now available. To get your hands on

Best Visual Studio Code Extensions

Visual Studio Code is a great free editor from Microsoft. This post will present you with our list of essential extensions for Visual Studio Code (vscode).

New Video Tutorials Published

Recording and publishing video, is something that we have done from time to time. We never really had a good series of videos, explaining the different features available on elmah.io. Until today! We've published 8 short tutorials on the elmah.io YouTube channel. Each explain one of the overall

Make your elmah.io dashboard ubiquitous

This is a guest post by J. Pablo Fernández, the founder of Dashman. Dashman is an online service that helps you control what to put on your wall-mounted big screen tv's. There are two ways of knowing the health of your .NET application: Receiving alerts when something goes wrong Looking

New Hire at elmah.io: Eduard-Dan Stanescu

Time for another new face here at elmah.io. Since loosing one of the co-founders, we have been in serious need for a frontender. We finally managed to find the perfect fit for the job: Eduard-Dan Stanescu. Eduard is a versatile developer from Romania, with an very impressive history. In

Tuning performance on Azure websites using remote profiling

We all introduce performance problems from time to time. Using this post, you will learn how to use the built-in performance profiler on Microsoft Azure. Using nothing more than Visual Studio, I'll show you how to dig into your call stack to locate bottlenecks.

Supporting NLog 4.5 and structured logging

NLog 4.5 were published a little over a week ago and we want to show our support with a compatible version too. As of today, our integration (Elmah.Io.NLog) runs on NLog 4.5 and also supports the new structured logging feature available in 4.5. All samples

GDPR changes

We are actively working with GDPR compliance, which will result in a series of minor adjustments to the UI and new features. We won't inform you about every little change, but here's an overview of recent changes. When signing up, you will now be prompted to accept both terms and

Domain name expires check

Ever wondered what will happen if you forget to renew your domain name? This actually happened to me (with another domain than elmah.io). I'd moved address and when the registrar failed creating a transaction on my credit card, they tried contacting me on the last known address. Domain lost.

Filters help you stay within your message limit

Since launching this feature, all of the integrations with elmah.io now have local filtering options. We recommend you filter unwanted log messages on your side to avoid you hitting API request limits, reducing outbound network traffic, etc. For instructions on how to create client-side filtering, look up the documentation

Search Filters to the Rescue

Searching your logs has been a key feature since we launched elmah.io. In fact, missing search capabilities in files and ELMAH (the open source project), was the main driver for me to start coding elmah.io back in 2013. elmah.io is built on top of Elasticsearch, which makes

How to read a file with C#/.NET - Avoid the common mistakes

Learn how to correctly read files with C#/.NET and avoid common errors with our beginner's guide. Enhance your programming skills today!

Turning a ASP.NET Core website into a Progressive Web App (PWA)

Progressive Web Apps (PWA) is a principle covering quite a lot of different web requirements, but what they all have in common are that they better the user's experience. In this post, we'll explain what a PWA is and show you how to turn your ASP.NET Core app into a PWA, using only a few lines of code.

New Advisor at elmah.io: Simon Langli

Time for a new face here at elmah.io. This time I want to introduce you to a person, that you probably never will get a chance to meet: Simon Langli. We are nerds at elmah.io and don't know a lot about sales and marketing (why we are partnering

List of the Best Free Visual Studio Extensions

Visual Studio is a great development environment. But with a few extensions, it will be even better. There's a lot of free extensions out there, that will improve the experience of writing code and even help you reduce bugs too. We have collected a list of the best free extensions for Visual Studio.

SSL certificate checks and new Uptime Monitoring emails

If you feel like we've given you the silent treatment over the last couple of weeks, it's simply because we have been coding all day long. Today, we are ready to introduce the next chapter in elmah.io Uptime Monitoring. Actually we want to introduce two new features, which are

Building a command-line tool with progress bar in .NET Core

Tutorial on building a command line tool with progress bar in .NET, using the Microsoft.Extensions.CommandLineUtils and ShellProgressBar NuGet packages. Building a command line tool using .NET Core makes it possible to execute it on both Windows, Linux and Mac.

Migrating to the options pattern in the client for ASP.NET Core

We just released a new version of our integration for ASP.NET Core. The new package follow the pattern around configuring other pieces of middleware more closely. The old method is still available, but marked as obsolete. By switching to the new API, you will get an improved configuration flow

Increasing storage at same low cost

We are proud to be able to constantly add new features to elmah.io, without making the product more expensive. While we have kept our prices steady over the last 4 years, elmah.io changed a lot during that time. Once again, we are happy to announce even more free

Delete messages in bulk

The most sought after feature on elmah.io has been deleting messages in bulk. Although we would've liked to offer this feature in the past, it has not been possible. So far, we have counted logged messages by looking at how many errors that are actually stored. To make sure

Exporting data from elmah.io

A common request through the elmah.io support is: how do I export my data? The reasons for exporting data may be: Import into Excel or similar for custom processing and graphing. Backup of old data. Switch to another error management system. Let's make one thing clear. The log messages

CryptographicException: The key ... was not found in the key ring (IIS)

CryptographicException: The key was not found in the key ring is a common error happening when hosting .NET code on IIS. Learn how to fix it.

Working towards GDPR compliance

You may have heard about GDPR or the General Data Protection Regulation. It's a new set of directives that every company dealing with EU citizens needs to follow. We are working with an external law firm to make sure that we comply with the new set of rules and guidelines.

Introducing Uptime Monitoring

Something struck me back in December. We've written a lot about the new Uptime Monitoring feature on the blog, our newsletter and more. But we never actually introduced the new system as a whole (which probably just shows that we are more nerds than business men :). So, either forget everything

elmah.io User Survey 2017

Back in December, we decided to try out something new. Some of the tool vendors we look up to, send out a yearly user survey. We talk with a lot of our users through the support, but when thinking about it, a survey seemed like a good idea to measure

New Hire at elmah.io: Kristoffer Strube

Everyone, please welcome Kristoffer Strube to the elmah.io team. Kristoffer is a young up-and-coming star, hired as a student programmer on elmah.io. I'll let Kristoffer introduce himself: "Hi, I'm Kristoffer. I’m originally from Horsens, Denmark, but right now I live in Aarhus where I have started

Follow all changes on elmah.io

If you are a recurring reader of this blog, you know that we announce major new features here once in a while. Major new features are not the only priority of the elmah.io development team. We constantly make adjustments, fix bugs, create minor features not worth mentioning on the

Great .NET Conferences to Attend

Ever googled .NET conferences and found the search result to center around the big Microsoft conferences only? Search no more. This is the ultimate list of conferences to attend as a .NET developer.

Continuous Deployment of Azure Functions with Slots

Tutorial for setting up Continuous Deployment of Azure Functions using deployment slots and auto swapping features on Microsoft Azure.

Mark errors as fixed, dashboards and more

With the new issue tracking feature on elmah.io, you will get a much better overview of which errors to fix.

.NET Blogs to Follow - The Ultimate List

The ultimate list of .NET bloggers, will help you become a better developer. Whether you code WinForms or like living on the edge, here is something for you.

Supporting Azure Functions and WebJobs

Introducing native support for logging uncaught errors from Azure Functions and WebJobs. Monitor your serverless code with ease.

Root cause analysis to the rescue

With Root Cause Analysis, you get a particular set of skills. By combining the client and server perspective, fixing uptime errors have never been faster.

Stable v3 API and client integrations

We've just published stable versions of all client integrations utilizing API version 3. Swagger endpoint, request throttling and more now built in.

elmah.io NuGet packages revisited

An updated overview of the client integrations available for elmah.io.

Enforcing message limits

Today, I want to share some future plans with you. We have been planning changes to the message limit on elmah.io for some months now. elmah.io always had a maximum number of messages available on each plan (like 5,000 messages per month on Small Business, 100,000

Extending the usage graph

Since we launched Usage Monitoring last year, we almost get no questions about how much space you guys use on your subscription. The difference between plans on elmah.io are primarily based on the included storage. Some features vary from plan to plan as well, like the allowed number of

Deployment Tracking and Uptime Monitoring included in plans

I'm pleased to announce, that we are now able to offer both Deployment Tracking and Uptime Monitoring to all of our users. Previously, Deployment Tracking were a paid add-on and we had similar plans for Uptime Monitoring. As of today, all users on the Business plan and up, will be

What is DevOps - A development process or a set of tools

Confused about DevOps? This article will teach you about the history of DevOps, the basic principles and how to implement DevOps in your organization.

Microsoft Azure Functions problems and troubleshooting

A compiled list of common questions and answers we've used when troubleshooting Azure Function problems.

Monitoring Azure Functions with the Portal and elmah.io

A guide to monitoring execution of Azure Functions, using the built-in tools provided by Microsoft. As a better alternative, you can use the power of elmah.io.

New features and improvements using a new chart control

Using Chart.js, we have improved existing graphs as well as created entirely new visualization on the various dashboards on elmah.io

Configure and deploy Azure Functions with Kudu

A guide to configuring and deploying Azure Functions with Kudu.

Migrating a Topshelf consumer to a Function running on Azure

Show you how to migrate an existing .NET Windows Service reading messages from Service Bus to a Function running on Azure.

An introduction to Azure Functions and why we migrate

An introduction to Azure Functions and the rationale behind porting parts of elmah.io from Windows Services to Functions.

Storing Content-Security-Policy reports in elmah.io

Utilize elmah.io to store actual Content-Security-Policy errors happening in your users browsers. We've developed a simple proxy to make it easy.

Content-Security-Policy in ASP.NET MVC

In this post, I'll explain the Content-Security-Policy header and how to set it up in an ASP.NET, MVC or Web API application. For existing websites, I'll show you how to add all the required bits gradually, by utilizing tools built into most modern browsers and elmah.io. Make sure no-one injects code on your website.

New error impact email highlights repeating errors

The Error Impact Increased Email notifies you when one or more errors happen more frequently than usual.

Improving security in ASP.NET MVC using custom headers

Improving the security in your ASP.NET MVC and Web API app is easy using custom headers and a bit of C#. Using this guide, you will learn about the entire list of headers needed to make it hard for hackers to exploit your website. No need to browse through outdated blog posts or MSDN articles. This is all you need.

ASP.NET MVC Interview Questions

A friend of mine had to hire a developer to implement a web based system in ASP.NET MVC. Since my friend know that I use both ASP.NET MVC, ASP.NET Web API and ASP.NET Core, he asked me about which questions to ask during the interview. Let

Enrich ELMAH errors using error filtering hook

In this post, I will show you how to enrich an error using error filtering with custom data before sending it off to the configured ELMAH store.