Typing API Responses With Zod

Have you ever needed to synchronize types in your frontend app with the backend API?

If you ever had an API action defined like that in your controller:

public record UserViewModel(Guid Id, string Name, string LastName, string Login,
bool IsActive, int LoyaltyPoints, AddressViewModel? Address = null);
public List<UserViewModel> AllUsers()
var usersViewModels = TestDataGenerator.GetTestUsers();
return usersViewModels.OrderBy(uvm => uvm.Name).ToList();

and fetched this data using TypeScript in the following way:

getAllUsers = async (): Promise<UserViewModel[]> => {
const url = `${this.apiEndpoint}/AllUsers`;
const response = await fetch(url);
const users = (await response.json()) as UserViewModel[];
return users;

at some point, you probably also experienced the desynchronization of backend (C#, in our example) and frontend (TypeScript) types definitions. What if someone has changed the C# version of UserViewModel, but no one corrected its TypeScript’s equivalent?

Your TypeScript fetching code will tell nothing about that. There will be no error, even though the fetched data doesn’t match the expected UserViewModel type.

I’ll try to address this issue in this article 🙂 Let’s see how typing API responses with zod can help us here.

Write Test Progress To The Console With NUnit

NUnit: writing test progress to the console

I recently needed to write test progress to the console with NUnit. The task we want to solve here is basically the TODO part of this snippet:

public class MyTests
public void SampleTest()
// some operations here, like starting a server for tests in-memory…
// TODO: inform the 'user' (the one who runs the test) that the server is already running
while (true)
// keep it running on purpose (e.g. for E2E tests)

The title picture of this article shows the end result. If you want to know the solution, keep reading 🙂

How To Fix SqlException Database Is Not Currently Available On Azure (0x80131904)

I recently deployed my .NET 6 application to Microsoft Azure. The app uses NHibernate for working with SQL Server database. After some time, I started getting an unhandled exception when opening the application:

NHibernate.Exceptions.GenericADOException: could not load an entity: 
 ---> Microsoft.Data.SqlClient.SqlException (0x80131904): Database 'myappdb' on server 'myapp.database.windows.net' is not currently available.  Please retry the connection later.  If the problem persists, contact customer support, and provide them the session tracing ID of '{EB501CF2-2F21-4E28-9042-2B83EEE57B91}'.

The database is not currently available was very interesting to me. I struggled a bit with solving that, so if you want to know how I did it – continue reading 🙂

Is It Worth Migrating to TypeScript?

Is it worth migrating to TypeScript?

For the past year I’ve been working on a JavaScript project for my client. We have a mid-size web application. We use React as the web development framework. Few months ago we decided to start migrating to TypeScript.

Today I can say that it was the best decision we could make. TypeScript makes working with JavaScript, which is sometimes surprising and quite hard to understand, so much better experience. However, there were some challenges on this journey. If you want to know what issues we met and how we solved them, but also what huge advantages TypeScript gave us – read on 😉

I will not discuss TypeScript itself in this article. This is a pure recap of challenges and the experience I gained when migrating to TypeScript.

[.NET Internals 10] Application execution model

Knowing the idea and main benefits of JIT compilation from the previous post, we’ll now see how it fits into .NET applications execution model.

By execution model I mean a process of having a .NET Framework application actually executed on the machine (CPU), starting from having its source code written. It contains all steps and actions necessary to happen in order to transform source code (like C#) into machine (assembly) code and execute it.