Microsoft creates the TypeScript compiler with Go

Microsoft has found itself in massive online drama again, this time because it chose to use Go instead of its own product, C#, to create a TypeScript compiler.

1 - Origin of the problem

Yesterday, March 11, 2025, Microsoft made a huge announcement that it had developed a compiler for TypeScript to another language, making it native code. Up to this point, everything seemed great, and the initial results look incredible since it's 10 times faster than the current implementation.

You can read the full announcement at this link: https://devblogs.microsoft.com/typescript/typescript-native-port/

The problem comes with the choice of language. Migrating from JavaScript to other languages is common for performance reasons, but Microsoft's choice was to use Go instead of choosing an in-house language like C#, and the community went wild.

2 - Has Microsoft killed C#?

Now the question comes from the C# users, in other words, developers outside Microsoft. If Microsoft itself doesn't use C# for its own implementations, does it mean they're killing it?

I see both sides of the coin.

The choice of Go is clear for those who read the explanation (https://github.com/microsoft/typescript-go/discussions/411), and after analyzing a ton of languages, Go turned out to be the best for performance and portability. This fits what we always say about choosing the right tool for each job.

In the original interview, referenced in the first link, they mention keeping memory usage very low to make better use of the CPU cache.

At the end of the day, Go was chosen to create a TypeScript-to-native compiler, which is a very specific task.

Now, I also see the other side, where managers with less technical knowledge see this news and say, "if Microsoft uses Go, we're not going to use C#". These decisions are often made by people with just a bit of technical knowledge, but who don't actually work with it daily. For example, a product manager, who really shouldn't have a say, but they went to a conference where the loudest message was that Microsoft doesn't use C#, they use Go.

What's important about this decision is to understand the technical reason behind it, not just read the clickbait headline or the thumbnail I might put on YouTube to try to get clicks.

2.1 - Will companies stop using C#?

My opinion is no, the use of C# will continue or should continue just as if the compiler had been written in C#, Rust, or Zig.

In fact, I'll say something else: even if we didn't get a new version of C# in the next three or four years, "nothing would really happen" since it's already a very complete language as it is. I'm sure the vast majority of you don't have all your apps on NET 8, even though it's the only supported LTS version of .NET right now, since support for .NET 6 ended in November 2024.

In conclusion, the choice of Go for this specific tool comes down to clear technical reasons. It doesn't mean the end of C#, and the community should focus on understanding the technical motivation behind the decision rather than falling into alarmism. Besides, Microsoft already has plenty of products where it doesn't use C#, and nothing happens.