In many ways, C# is a great language. (So is F#, for the record).

It might well be better than e.g. Java but overall it's not better _enough_ to incentivize switching.

A lot of it is vibes as well. Most people think .NET is bloated, closed off, hard to develop on non Windows machines, etc. It's made progress on those, but has it made enough to be worth gambling on?

Ultimately you can just stick with Java, avoid the risk, and not suffer any real consequences. Maybe try Kotlin if you're feeling daring, but even then modern Java has largely caught up.

If the company is full of TS/Python/Go-oriented people then it's an even bigger leap. For many of those guys you can also add on the _enterprise_ stigma. It would be like expecting them to pick Oracle.

I've worked for a number of startups that use Java even though there is a reputation that startups don't use Java.

A long time ago I worked for a company that was moving into web-based products from consultancy work making decision support software for how to allocate sales forces. We were using Microsoft Silverlight on the front end and ASP.NET on the back end which was cool because we could share some of our C# code between the front end and back end. This company saw itself as a "Microsoft shop", we had Microsoft IIS as a database, we all had subscriptions to MSDN which meant software developers got copious licenses for all the Microsoft products we wanted, etc.

I think there's a cultural thing where people see themselves in Microsoft's orbit or not so a lot of Linux-inclined people wouldn't consider C# although that's not entirely rational in that Mono is a great open-source implementation of the CLR.

The area where I've seen the most C# is gamedev. In the PS3 era Sony had a bit of a crisis because it was hard to write code for the PS3, ironically they saved the situation by adopting C#/CLR from Microsoft and producing

https://en.wikipedia.org/wiki/PhyreEngine

which would let you write games portable between the PS3 and PS Vita and other platforms. A lot of other game frameworks like Unity and Godot also use C#, so a lot of indie game developers code in C#.

It's been overshadowed by Python which has a sexier image because it isn't associated with Microsoft. It certainly doesn't help that in the beginning C# was a Windows only language tied to the .NET framework. It's taken a decade for word to get out that it has evolved past that.

Because Microsoft is not a reliable partner;

Just recently:

- they removed dotnet hotreload overnight for it to become gated behind a visual studio license

- they forced jetbrains to stop shipping the dotnet debugger in their IDE overnight, screwing their plan for their IDE Rider, they had to write a debugger from scratch

- their language server is still closed source and VS only

1. https://www.theregister.com/2021/10/22/microsoft_net_hot_rel...

2. https://blog.jetbrains.com/dotnet/2017/02/15/rider-eap-17-nu...

I've written extensively about this previously here: https://www.reddit.com/r/dotnet/comments/16fu7o0/comment/k03...

I've also used C# at a VC-backed, SV startup (raised $8m seed). It was fantastic and we were able to move very fast on the backend. The tooling is stable and much better to work with than TS IMO. It wasn't any harder to hire for, IME. We had two very junior engineers (college grads) who were able to pick it up pretty easily as it has a strong resemblance to TypeScript these days[0]

I am in the process now of spinning up C# at a series-C YC startup so we'll see how it goes. The team started in JS and moved to TS 3 years back. Now TS is showing its rough edges (lack of runtime types, poor-man's ORMs that all have issues, complexity of TS ops at scale (multiple build chains, tooling, breaking changes, lack of standard libs (it was a bit of a quirk to me that DB transactions between Drizzle and Prisma didn't work -- then I realized that they don't have a common transaction layer))).

C# is very, very underrated and I can understand why more startups don't use it, but more startups should definitely give it a look.

[0] https://typescript-is-like-csharp.chrlschn.dev/

I think C# and .NET in general are excellent in 2025. It is not as popular with startups because:

- Microsoft and Windows only stigma. Most people don't realize how far the ecosystem has come along since .Net Core etc. People still think its living the era of "Windows only"

- Historical ties to Windows only database like SQL Server. Most people who have worked in C# in a corporate env. were used to it with SQL Server which is not free and requires a license. It doesn't compete well with likes of MySQL and Postgres even though you don't really need SQL server anymore.

I think these are the 2 biggest reasons. Personally, I think C# is amazing and would totally use it to build a startup if I had to.

C# is great but you will spend the first 6 months of development trying to find a web or UI framework that doesn't suck.