Amazon was specifically using Clojure for the online checkout system, and the team bragged a few years ago how the system survived black friday without a hickup.

Walmart is using Clojure for their checkouts as well https://www.youtube.com/watch?v=av9Xi6CNqq4

Boeing is using it in the onboard control systems for the 737 Max https://www.youtube.com/watch?v=iUC7noGU1mQ

It's not some obscure microservice that some intern wrote over the weekend, these companies are using the language for critical applications, and the feedback from these companies is positive.

The online checkout system isn’t a single service. I personally worked with the Delivery Promise service for a short time, and that service was composed of 8 different services...and that was just to calculate when we promised arrival to the customer during checkout. As in, they were just a single component of hundreds called during checkout. At the very least, none of those 9 services used Clojure.

If anybody led you to believe that their team did “online checkout”, but didn’t care to explain how small of a cog they were in an extremely complex system composed of hundreds of services, then you were grossly misled.

I linked a talk from Walmart that explains exactly how they're using Clojure. I don't think I'm misrepresenting anything here.

You absolutely are. You name dropped Amazon as some sort of proof that Amazon is used at scale, completely misrepresenting the scope of usage. Simply put, Clojure at Amazon is an insignificant and inconsequential symptom of a massive service oriented architecture with tens of thousands of software developers across four continents making independent decisions on how to write their tiny services.

I think anything that's part of the sales chain can't be dismissed as insignificant. Just because Amazon uses other technologies, that doesn't diminish its importance.

I can appreciate your desire to share the good news about Clojure adoption, but I don't think the language is in need of defense. It's used a lot all over the place, and you shouldn't feel the need to convince others of that. Because even if it weren't used hardly anywhere, it would still be a great tool for those of us who do use it. That it is in fact in use in a lot of places, regardless of its specific role, is just a nice added bonus.

If someone doesn't want to use it for this reason or that, it's their loss not ours. Those who need to find Clojure eventually will, because there is nothing else like it.

The Boeing video says Clojure is used for maintenance systems, not control systems. That’s an important distinction. Maintenance systems can go offline and the aircraft still flies fine. The critical control software is not written in Clojure from what I could tell.

Critical software is rarely written in anything except languages with explicit memory control, usually C++, and usually with very strict guides. There is a famous programming guide for flight control systems in particular that discusses how to properly use C++ for maximum safety during flight. It includes things like never allocating memory after take-off.

You wouldn't want Clojure, Java or any languauge with GC running in a pacemaker either. Those are all also very important distinctions.

The majority of critical software is C, sometimes it's C++ or Ada instead.

C++ actually proved difficult to adopt over C. The language is too difficult and the tooling is too poor. It's too hard to run a static analysis or prove 100% code coverage.

I'm not sure what your evidence is for this, but I find C++ to be used far more widely than C in nearly all the companies I interact with that do critical low level work. And there is indeed plenty of information in the industry about flight control software in particular in C++. It's also very popular for embedded work, because C++ allows you to offload quite a bit of work to compile time that can only be done in C at runtime. And I've attended talks for security systems in C++ specifically because of control over exceptions and how to track unexpected events, which is something security professionals are very interested in.

With regards to tooling, the windows visual studio experience for C++ is widely counted as one of the best development setups in the industry for any language. I know lots of people working in other languages that envy what C++ developers get.

I agree with you that it's not necessary or meaningful to "name drop" companies that use some X technology as an indication of its worth. Languages and tools don't need a massive following by enterprise to be incredible and revolutionary. It's like a really good movie that didn't have a large audience but was nonetheless really awesome for those who did see it. That's a lot like how I think Clojure is.