Zig has been in the news a lot recently but I haven't explored it much other than a few tech talks which seemed interesting.

I wonder if this is it's killer feature - compatibility with the C ABI.

> compatibility with the C ABI

Almost all non-C language offer that feature. The additional thing of the Zig toolchain is that it can also compile C/C++/ObjC projects without requiring a separate compiler toolchain, e.g. the Zig compiler toolchain is also a complete C/C++ compiler toolchain.

Almost all languages provide a method of calling C generated code for sure. But, as I understand it, this is usually a more tortuous path than straight ABI compatibility.