Node.js vs .NET: Which is Better for Backend Development

• .NET
  .NET has an established base, which makes this framework quite clear and easy to understand despite the slight changes and improvements that may be implemented in the future. It has a convenient mechanism for data sets handling and division into types. Projects may be written with older C# versions, but they are easy to maintain in the future. The main reason is that the framework has out-of-the-box functionality and is statically typed. This means that when you write code, you declare a type. It can be a digit, a string, an essence, whatever. You declare a type which is not subject to change. For example, you have an application for a restaurant and you’ve declared a glass of wine type. And you can not change this type to another one, say, for a glass of beer. If you need another type, you have to declare a new one (a glass of beer) and work with it (or derive it from another type). 
  
  At first sight, it may seem that you have to take additional time-consuming steps on the way to high-quality code. But exactly static typing feature ensures the clearness of the code in the future for you and your colleagues in the shop — even if the customer hires another team for the project years after, the successors will not experience any difficulties when proceeding with any amendments or creating a new feature.

• Node.js
  Considering Node.js, the situation is different. The framework is not statically typed, and the programmer creates features by using one of the many libraries and templates for a huge variety of use cases. There is no necessity to declare types because there are no custom types built in the framework, and a nominal glass of wine can be changed to a glass of beer on the fly. On one hand, this is a strong point of the framework, because the framework is maximally flexible, the development speed is fast, and you are able to write the working backend and present it to the customer within several days.  
  
  On the other hand, it affects future application maintenance, because when you come back to your code without types months later (or another team makes amendments or improvements in the app) it will take a decent chunk of time to sort it out and add new features. But this problem can be partially solved with TypeScript, a syntactical superset of JavaScript, which allows working with types as in .NET. 
  
  Utilizing Typescript interfaces, classes, the principle of polymorphism — all the problems can be bypassed, and the project will be well-structured. Splitting the application into separate modules, we gain three main essences: a controller, which processes the requests; the service which plays a role of the layer, in which we can proceed with different modifications; the repository, which communicates with the database.

• .NET
  Static typing characteristic of the .NET framework ensures easy test coverage of the written code. Splitting the code into patterns and breakdown into modules helps to sort the code out, see the boundaries clearly and understand which parts contain business logic and require mandatory testing.
  
  
• Node.js 
  The absence of default built-in types makes Node.js more challenging to test. For example, let’s consider a medical application. It parses the file to extract the data and handles a range of analyzes. But in the application code, you can’t make out what is what because there are no custom types  (you still can emulate them but it will take much more time than with .NET) and you are not able to differentiate one analysis from another. This hinders the testing process as it’s difficult to allocate separate modules and therefore understand where is a part of the business logic and where is a part that does not require testing at all. However, TypeScript can simplify testing of the application written with Node.js, but the process will be still more complex than in the case of .NET.

• .NET
  .NET has not always been a cross-platform framework. The functionality was added several years ago when the .NET Core version was released. If an application was written with the older versions of .NET it could be migrated to the later versions to leverage the potential of cross-platform. The complexity of app migration depends on several factors: the complexity of the source legacy code, of the database, and whether there is an ORM in use. 
• Node.js 
  Node.js was initially created as a cross-platform framework. From the very beginning, it supports different servers and users can access the apps from devices powered by any operational system, be it Windows, Linux, or macOS.

• .NET 
  .NET showcases outstanding performance due to multiple improvements implemented by Microsoft and memory management. Programming languages belonging to the framework are high-level, which means that they do not communicate with the memory directly. But C# has a feature that allows switching to the lower level closer to the memory and managing it manually, for example, deleting unnecessary elements affecting performance. 
• Node.js
  Node.js is now a universal framework, although it was initially designed for web app creation. Unlike .NET programming languages, those belonging to the Node.js framework don’t have such a feature of switching to another level and utilize garbage collectors only to manage the memory. This means that the performance of those apps written with the frameworks featuring this peculiarity will always surpass the performance of those lacking it, which makes the framework not very suitable for CPU-intensive projects.
  
  Node.js can not withstand high loads. It showcases outstanding performance on small projects, but when the application grows fast, leaving it as a monolith is not the best solution. When the app is growing from an MVP to a full-fledged project, it’s better to move away from the monolith and consider splitting it into microservices.

• .NET & Node.js 
  Good scalability of both .NET and Node.js frameworks is achieved through integration with Kubernetes or Cloud. Written applications and databases can be hosted in the Cloud, CI/CD (Continuous integration, continuous delivery.) pipelines with tests and performance metrics can be added. There is no need to deploy and configure it manually, Cloud or Kubernetes will take it over and scale when needed.

• .NET
  Not everyone is willing to wait months to gain a working application knowing that they can gain it within days. Low development speed is the main drawback of the .NET framework making many business owners decide in favor of other technologies. Writing code with .NET, the developer is responsible for its quality by default. Because declaring types is mandatory in the group of .NET programming languages and you have a built-in MVC (Model-View-Controller) pattern you have to follow. At the level of the framework, you have to write the model, the view, and the controller separately; it can not be altered at the will of the developer to speed the process up.
• Node.js
  Node.js gained its popularity because of its simpler rules and fast development speed. Absence of strict predefined framework rules, no need for types declaration leave programmers a lot of space for maneuvering, and make the Node.js framework maximally flexible. Moreover, Node.js has built-in support of JSON (common data format), which makes the development speed even faster.
  
  However, you need to keep in mind that speed does not equal quality. Say, you hired the team to build an application. They’ve completed the mission successfully within weeks. You are totally satisfied with the result and don’t understand those waiting for their apps for months to be built. You utilize the application, develop your business, and there comes a day you realize that you need a new feature urgently. Remembering the speed your application was built with, and supposing that adding a new feature will be as easy as pie, you hire a new team for implementation. And this team shocks you with the news that it will take months! But how so?
  
  The reason is that the new team needs additional time to sort the code out if the previous team did not pay due attention to the quality and didn’t apply TypeScript for development. In the absence of written types, the programmers will not understand what is what and will have to waste time decrypting the convoluted lines of code.

• .NET 
  .NET is now positioned as an open-source framework, however, it is not entirely true, which explains the smaller community size in comparison with Node.js. Microsoft engineers are closely watching the framework quality and have their own rules and a roadmap of features approval. However, the framework is moving towards the full open-source format. When it was just created, programmers were even not allowed to see the source code of the framework, not to mention proposal submissions from engineers. 
• Node.js 
  Node.js was initially designed as an open-source framework and has a big community across the world. The framework source code has never been hidden, and engineers could check it and put their suggestions forward at all times. The framework underwent multiple improvements thanks to engineers from different parts of the world, which made the framework really community-driven.

Another disappointment and tiresome “it depends”. We totally understand that you are tired of this phrase but there is no definite answer to the question. First of all, the choice of the framework depends on the domain and project type. If the domain is complicated (for example, Insurance or Healthcare), the application implies complex business logic and multiple rules, and is CPU-intensive, it is reasonable to pay special attention to the quality, accuracy, testability, and future maintenance, and it’s all about .NET. Yes, you will not gain your application by waving a magic wand. It will take time to work with types and follow the framework rules, but scrupulous work at the initial stages saves your time and effort for future app maintenance and improvement in the future. In short, with .NET you build your app within months, but implement future changes within days, while with Node.js the case might be diametrically opposite: you build your app within days, but implement future changes within months if you don’t strictly monitor the code quality. 

Meanwhile, if you need to build something that does not imply complex user actions —  a business card site or an admin page, data streaming apps, SPAs —  it doesn’t make any sense to bother with types and utilize .NET. Node.js will be a perfect choice here, as the framework is relatively simple and lightweight. But still, Node.js is sometimes chosen for CPU-intensive projects and complex domains. This can be done, especially with the support of TypeScript, and external tools for ensuring code quality (static code analyzers, Linters).

Both .NET and Node.js frameworks have their advocates and opponents. They are time-tested, have big community support across the world, and are continuously being improved. 

This is not to say that one framework is better or worse than the other one. They are both different, have their own good and bad, and showcase outstanding results if selected for proper application types. For small and medium-sized projects lightweight Node.js is a perfect choice, while more complex long-term projects require more reliability embodied in .NET technology. However, the rapid development gradually blurs the boundaries between the frameworks, and maybe one day the need to choose will disappear.