A Fight Over a Programming Language: Why Zig and Zen Are at Odds

The Zig Software Foundation recently published a public statement raising concerns about Zen, a related programming language. The problem involves two things: how Zen's makers plan to make money, and whether they properly credited code they borrowed from Zig.

Think of it like someone taking an open recipe from a cookbook, adding a few tweaks of their own, then selling their version of the dish while charging customers a fee to use it in their own restaurants — without clearly saying where the original recipe came from.

What Is Zen, and How Does It Connect to Zig?

Zen is a programming language built by a company called connectFree, founded by Kristopher Tate. Programming languages are tools that tell computers what to do. Think of them as different ways of writing instructions — like how you might give directions in French, Spanish, or English, but the destination is the same.

Zig is an open-source programming language, which means its code is free for anyone to look at, use, or modify. Zen branched off from Zig but is now closed-source, meaning its code is kept private by connectFree.

The key issue is that Kristopher Tate was not some outsider. He was the fifth-largest contributor to Zig's development — meaning he was one of the people who helped build it. When someone who helped create an open project then builds a commercial product partly based on that work, the original creators take notice.

The Money Problem

ConnectFree wants to charge software developers a yearly subscription fee. If you want to build a program using the Zen compiler and distribute it to others, you have to pay this subscription. This is very different from Zig, which is free to use, modify, and distribute — forever, with no fees attached.

For professional programmers and companies, this matters. Using a compiler that requires a yearly fee means adding an ongoing cost and dependency to your toolbox. It also means your legal and compliance teams need to review it carefully. In industries like aerospace, medical devices, or finance — where knowing exactly where your code comes from is critical — this kind of vendor dependency can be a serious problem.

The Zig Foundation is not saying the licensing model is illegal. But they are saying it raises questions about using Zig's free code as the foundation for a product that charges others money.

A Specific Code Question

The Foundation also points out that Zen uses a technical feature called async/await — a way of handling multiple tasks at once — that was first built for Zig. The Foundation says Zen copied this functionality almost exactly from Zig, without much modification.

Under Zig's free license, copying is technically allowed. The license just asks that people give credit and show who originally wrote the code. What the Foundation appears to be questioning is whether connectFree did this properly, and whether their story about building something independent actually matches what happened.

It is worth stepping back here to note that the Foundation is not saying forking a project is wrong. Open-source software depends on the right to fork — to take something, improve it, and build on it. What appears to concern them is the combination of copying code, locking it behind a proprietary compiler, charging subscription fees, and then claiming the result is largely independent.

This Has Happened Before

Over the past thirty years covering technology, I have seen this pattern repeat. In the early 2000s, companies built commercial products using free software from projects like Linux, then ran into public disputes about how they were using that code. The details change, but the underlying tension is familiar: someone who once helped build a free project leaves, makes money from the work they were part of, and the original creators feel they need to set the record straight in public.

These situations rarely end up in court. More often, reputational pressure leads to the company quietly updating how they credit the original work or adjusting their public messaging. It is a way of establishing norms for how people should behave when they take free code and commercialize it.

Why the Foundation Went Public

The Zig Software Foundation is a nonprofit organization created by Zig's original author. Publishing a named statement like this is a significant move for an organization of this type. It signals that the Foundation considered the situation serious enough to address directly, rather than let people debate it only on social media and forums.

You can read the full statement at ziglang.org/news. The language used is measured and not angry, but the concern is clear.

What This Means for People Choosing Programming Tools

If you are a programmer considering whether to use Zig for your project, this statement does not change Zig itself. The language continues to be developed and improved. Version 0.16 was recently released, and the project moves forward on its own path.

If you have run into Zen and are thinking about using it, this is a good moment to look carefully at the licensing terms. A subscription fee to distribute what you build is not automatically a bad deal, but it is something you should deliberately choose with your eyes open — not discover after you have already built your entire project around it.

The broader context here is that programming languages become more valuable once people start using them in real work. Zig is gaining adoption in areas where performance and reliability matter most. That success makes it an attractive target for companies wanting to build commercial products around it. The Foundation's decision to respond publicly is a way of signaling what kind of behavior they expect from people who take their free work and commercialize it. Over time, moments like these help establish the unwritten rules of how this should happen.