Data validation is an essential part of application design and development, and telephone numbers are as tricky to validate as they are ubiquitous. In many cases a phone number will be the primary way your organization communicates with its customers. Whether the communication will be by voice, SMS, or messaging app, having a correct phone number is a requirement.

Developers using .NET Core and the .NET Framework can do validation for a number of different data types, including phone numbers, with the System.ComponentModel.DataAnnotations namespace, but the PhoneAttribute class has its limitations. To learn more, see the .NET Data Validation section of the previous Twilio Blog post on this subject: Validating phone numbers effectively with C# and the .NET frameworks.

Fortunately, the libphonenumber-csharp open source library provides extensive resources for validating and manipulating phone numbers of all types and it’s conveniently available as a NuGet package. This post shows …

This blog post is part of The Third Annual C# Advent by Matthew Groves which is a C# advent calendar.

Do you worry you're stuck on the naughty list? Have you forgotten all the good deeds and awesome things you've done over the past year to deserve more than a sack of coal?

Tracking your little wins as they happen is a fantastic way to remember your successes whether you're sharing the list with your boss or Santa Claus or just yourself!

We will use Twilio Autopilot to capture your accomplishments, thus enabling you to keep a log via SMS, voice, WhatsApp, Slack or even your Amazon Alexa or Google Home device!

We're going to save the output of Autopilot to Azure Table Storage via an Azure Function.

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

To get started, we will need:

• A Twilio account
• An Azure …

If you have a bit of familiarity with Polly, the resilience framework for .NET, you will know how useful the Retry and Wait and Retry policies are for handling transient faults and longer outages. But there are times when no amount of retries will solve the problem, the remote system is unresponsive, has been for a while and will likely continue to be so. In this scenario, cutting the connection to the failing system might be the best approach.

Polly lets you do this with its Circuit Breaker policies. The policies get their name from the circuit breaker in your home that cuts electricity to an outlet or fixture. Just like the real-world circuit breaker, the Polly Circuit Breakers cut your connection to a faulting system.

This post shows you how to incorporate Polly Circuit Breakers into your resilience strategy. You’ll build working examples with ASP.NET Core 2.1 and see …

With Twilio Programmable Video you can add robust video chat functionality to web applications built with Angular and ASP.NET Core. With the Microsoft Azure App Service you can host your video-enabled apps on a fully managed, enterprise-grade cloud platform. Deployment and configuration are easy and take just minutes.

Build a Video Chat App with ASP.NET Core 3.0, Angular 8, and Twilio showed you how to integrate the Twilio JavaScript SDK and the Twilio .NET SDK seamlessly with ASP.NET Core and Angular. This post will show you how to deploy applications built with these technologies to the Azure App Service.

In this post you will learn how to publish your application to the Azure App Service, and securely configure the app on Azure to use the Twilio Video Chat API with the App Service settings. You’ll be able to try out the production applications’ video chat features and verify that it’s …

In a previous post you learned how to take a fresh application and deploy it to a Kubernetes cluster. While it’s great to start with a new application, most of us don’t get that luxury. Usually, you’re going to start off with something older and have to refactor and then migrate it.

This tutorial will show you how to take an existing application, refactor it using cloud-native principles, and deploy it to Azure Kubernetes Services. By the time you’re done, you will know how to move your own applications to the cloud.

Cloud Migration Patterns

When migrating applications to the cloud, there are a handful of different patterns you can follow. Which pattern you choose will depend on what you are trying to migrate and how much time you want to spend migrating them. Each of these patterns has different tradeoffs, so it’s good to understand them all when looking …

Realtime user interaction is a great way to enhance the communication and collaboration capabilities of a web application. Video chat is an obvious choice for sales, customer support, and education sites, but is it practical to implement? If you’re developing with Angular on the frontend and ASP.NET Core for your server, Twilio Programmable Video enables you to efficiently add robust video chat to your application.

This post will show you how to create a running video chat application using the Twilio JavaScript SDK in your Angular single page application (SPA) and the Twilio SDK for C# and .NET in your ASP.NET Core server code. You’ll build the interactions required to create and join video chat rooms, and to publish and subscribe to participant audio and video tracks.

This post provides instructions and code for creating a video chat app with ASP.NET Core 3.0. To learn how to build the …

As a .NET developer, I've been excited to explore all of the great things that came with the release of .NET Core 3.0. I have spent time playing with one of the newly launched technologies, Blazor, which allows me to build web applications targeting web assembly using HTML, CSS and C#. 

In my excitement, I went to see what the fuss was about. Following the instructions on Blazor.net, I updated Visual Studio 2019, installed the Blazor project templates, created a new Blazor app project, and then realized there were some choices I needed to make in order to build my shiny Blazor web application. As I made some choices and got going with my project I continued to see more and more places where I wished some things had already existed to help make development easier. 

As a result, I've put together this list of tips to help sort …

It's an exciting time to be a .NET developer as .NET Core 3.0 has reached general availability. With this release comes Blazor, Microsoft's take on building web applications using WebAssembly and the technologies you already know and love such as HTML, CSS, and C#. I published a prior blog post when Blazor was still in active development. It's time to join the release party and share our excitement about Blazor with Twilio and C#.

The first thing you should do when a new product gets announced is tell your friends, right - but what if we phoned them with a special note sharing our excitement? Let's build a web application that does exactly that - it uses Twilio to phone a friend, and is powered by Blazor.

Installing Our Developer Tools

Now in order to follow along - you'll need a few things first. You'll want to grab …

We all have good days and bad days. On a good day, we may be filled with positive thoughts and on a bad day, we may forget that anything was ever positive!

In this post, we will use Twilio to text your positive thoughts and affirmations to an Azure Function and save them in Azure Table Storage. We will then create a timer-based function that will send a random happy thought from the table storage via SMS to your friends.

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

To get started, we will need:

• This GitHub project cloned
• A Twilio account and an SMS enabled Twilio number
• An Azure Account (sign up for free here)
• The latest .NET Core 2.2 SDK (download here)
• Azure Functions Core Tools version 2.6.666 or later
• Azure CLI version 2.0 or later
• Postman for testing our functions locally
• An IDE …

Using Polly, the resilience framework for .NET, you can gracefully handle lost packets, thrown exceptions, and failed requests which inevitably make their way into service-to-service communications on the web. Polly provides resilience strategies for your apps through policies such as Retry, WaitAndRetry, and CircuitBreaker, enabling you to implement fault tolerance in your distributed systems in a fluent fashion.

This post will introduce you to the Fallback policy and demonstrate its use in a straightforward ASP.NET Core 2.1 example. It will guide you in using the Fallback policy to handle failures you cannot recover from: when all else fails, fallback to this last line of defense.

If you’re not already familiar with Polly, the first post in this series on the Twilio blog introduced Polly, the .NET resilience framework. The second post build on the first and introduced the HttpClientFactory.

Prerequisites

To follow along with this post you need: …