Getting instant notifications when an error happens on a website can mean life and death for a business. The faster developers fix the bug, the fewer users get frustrated with your website. Using elmah.io and Twilio, getting SMS notifications when your ASP.NET Core application starts failing requires nothing more than a few lines of code. In this post, you will learn how.

elmah.io is a cloud-based error logging and uptime monitoring service for .NET web developers. elmah.io monitors your websites for crashes and outages and alerts you in real time when an event happens.

You can receive elmah.io alerts through a variety of channels, including Slack and Microsoft Teams, using integrations provided for those and other products. You can also receive alerts by SMS using the elmah.io integration for Twilio. With a Twilio Phone Number you can receive text notifications about your website wherever ...

Creating mobile apps with Xamarin involves more than just coding and pressing F5. Since your apps will be running on a mobile operating system like Android or iOS, testing and debugging them requires running them on a device running one of those operating systems or a simulation of a device.

The first post in this series showed how to get set up and build your first app in Xamarin with C# .NET. This post will show you how to deploy and run your Xamarin app on an iPhone or Android device. You’ll also learn how to deploy and run on iOS and Android emulators. With these techniques you’ll be able to test and debug a single app on a variety of devices and OS versions without needing a stack of phones.

Prerequisites

Visual Studio 2017/2019 for Windows or Visual Studio for Mac

Mobile development with .NET workload ...

Nearly everyone these days has a mobile phone, and most of these are smartphones. Everyone downloads apps, from social media to games to fitness.

As developers, a lot of you probably think about making an app for your phones. Whether it's just for a laugh, or to solve an actual problem, our curious minds get us thinking.

In this post you will get an introduction to how you can create mobile apps using C# and Visual Studio, taking advantage of the awesome Xamarin mobile tooling built into Visual Studio.

Today you will cover the following set of topics:

• What is Xamarin?
• What tools will I need?
• Getting started with the Visual Studio tools for Xamarin
• Creating a simple counter app
• Learning more

What is Xamarin?

Xamarin is a cross-platform mobile development framework that now ships with Visual Studio 2019 for Windows and Visual Studio for Mac.

It is a thin ...

ASP.NET Core Identity is a membership system that adds user sign in and user management functionality to ASP.NET Core apps. It includes many features out of the box and has basic support for storing a phone number for a user. By default, ASP.NET Core Identity doesn't try to verify ownership of phone numbers, but you can add that functionality yourself by integrating Twilio’s identity verification features into your application.

In this post you'll learn how you can prove ownership of a phone number provided by a user using Twilio Verify in an ASP.NET Core application using Razor Pages. This involves sending a code in an SMS message to the provided phone number. The user enters the code received and Twilio confirms whether it is correct. If so, you can be confident the user has control of the provided phone number.

You typically only confirm phone ...

Using Polly, the resilience framework for .NET, you can gracefully handle the lost packets, thrown exceptions, and failed requests which inevitably make their way into service-to-service communications on the web. A previous post on the Twilio blog introduced Polly, the .NET resilience framework. This post builds on that knowledge to strengthen your application's interaction with API endpoints.

The original .NET HttpClient was a convenient way to send and receive HTTP requests and responses on the web, but unless HttpClient was carefully implemented its use could result in socket exhaustion. The release of .NET Core 2.1 introduced HttpClientFactory, which can be instantiated once and used throughout the life of an application.

This post will show you how to combine HttpClientFactory with Polly to achieve efficient and resilient service-to-service communications. You'll see how you can do it more reliably, conveniently, and with less code than using HttpClient.

Prerequisites

To follow along ...

Over the last month we've climbed out of numerous programming rabbit holes thanks to fellow .NET developers writing public tutorials for the community. We've rounded up some of our favorites in this post.

Each tutorial listed below is easy enough for beginner-level programmers to follow. More experienced developers should be able to breeze through the code while building a useful project or using these tutorials as convenient refreshers.

Enjoy these awesome tutorials!

Making complex authentication easier

Are you excited about authentication? If so, please tweet us, you are a delightfully special breed of developer. Here are a few great authentication tutorials for those folks that aren't  as stoked about the topic and who just want to get the sign in page working.

Updating Microsoft Account Logins in ASP.NET Core With OpenID Connect And Azure Active Directory by Damien Bod

Add Authentication to Angular 7 App using ASP.NET Core ...

ASP.NET Core Identity is a membership system that adds user sign in and user management functionality to ASP.NET Core apps. It includes many features out of the box and has basic support for storing a phone number for a user. By default, ASP.NET Core Identity doesn't try to verify ownership of phone numbers, but you can add that functionality yourself by integrating Twilio’s identity verification features into your application.

In this post you’ll learn how you can prove ownership of a phone number provided by a user using Twilio Verify in an ASP.NET Core application using Razor Pages. This involves sending a code in an SMS message to the provided phone number. The user enters the code received and Twilio confirms whether it is correct. If so, you can be confident the user has control of the provided phone number.

You typically only confirm ...

Service-to-service communication is becoming more and more common, but we know the network has never been reliable and that other people's code has bugs. Packets are lost, exceptions are thrown, and requests fail; it will happen to your application—to all applications!
Using the Polly Resilience Framework you can easily retry a failed request, no messy for loops or try catches needed. Just a few lines of code and your applications will never be the same!

This post shows how to make reliable requests to an unreliable "remote" service with almost no overhead.

You’ll start with a “remote” Web API application that returns errors 75% of the time. Then you’ll build a “local“ Web API application that calls the remote one (of course receiving errors three quarters of the time).

Finally, you will add Polly to the “local” application to perform retires on failed requests. With a few ...

I love Bing Image of the day, it always makes me smile! I also love dogs, so I thought why not combine the two and create an app that sends a daily dog picture via WhatsApp.

This post will take you through all the steps to create an azure scheduled function in C#, make a call to the Dog API to retrieve a photo and then send the returned image to a number via the Twilio API for WhatsApp.

This post assumes some base knowledge of C# and RESTful APIs.

To get started, we will need:

• A Twilio account (sign up for a free Twilio account here)
• The WhatsApp Sandbox Channel installed in your account (go through this process to activate the sandbox)
• An Azure Account (sign up for free here)

Create an Azure Function

From the Azure portal, click the Create a resource button, found at the top of ...

An apt business use for both Twilio SMS and Twilio Sendgrid would be for customer enquiries on a website.  Using C# and .NET Core 2.2 we will build an app that receives an SMS, takes the from number and the message body and send out an email using Twilio SendGrid.

To get started with this project you will need the following:

• A Twilio account (sign up for a free Twilio account here)
• A Twilio SMS-enabled number
• The .NET Core 2.2 SDK and runtime
• A Twilio SendGrid account (sign up for free here)
• A SendGrid API Key
• Visual Studio Code or similar code editor or IDE

Creating the project

We are going to use the WebApi template project that comes with the .NET Core SDK, as a starting point.

From the command line, navigate to the location you wish to create the new application. Use the following command to ...