Microsoft’s 6502 BASIC Goes Open Source

On September 3rd, Microsoft released the source code of one of its very first products—one that had a massive impact on the history of computing: Microsoft’s 6502 BASIC.

Before MS-DOS and Windows, Microsoft was focused on creating BASIC interpreters. Back in the mid-70s, when Intel was just starting to make its mark, the personal computing landscape was fragmented across different microprocessors. Microsoft’s strategy was to deliver a BASIC interpreter for each platform. One of the most famous implementations was on the Apple II (though Apple rebranded it as “Applesoft BASIC”, it was originally written by Microsoft).

You can read more about this milestone here:
https://opensource.microsoft.com/blog/2025/09/03/microsoft-open-source-historic-6502-basic/

And browse the original assembly source code here:
https://github.com/microsoft/BASIC-M6502

Our Thoughts on Microsoft and BASIC

This open-sourcing is an exciting historical step—but it also reminds us of something bittersweet. It’s unfortunate to see how the very product that once put Microsoft on the map has been left behind.

Not only was Visual Basic Classic (VB6) discontinued in favor of VB.NET, but now even VB.NET itself has been pushed into “maintenance mode,” slowly fading away as Microsoft directs more and more energy into C#:
https://learn.microsoft.com/en-us/dotnet/visual-basic/getting-started/strategy

And the so-called “new features” in VB.NET are now essentially just extensions to support APIs created for C#:
https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-10/overview#visual-basic

https://learn.microsoft.com/en-us/dotnet/visual-basic/whats-new/

It’s hard not to wonder: what if Microsoft had embraced Visual Basic more fully? Take Python, for example. Its rise in artificial intelligence was driven largely by its simplicity and accessibility—yet under the hood, it’s just calling functions from C++ libraries. If Visual Basic had been given the same love and evolution, it’s not far-fetched to imagine a world where today’s AI frameworks might have been VB-first instead of Python-first.

What do you think?
Do you agree that Visual Basic deserved a different fate? Could it have been the language powering today’s cutting-edge tools?

We’d love to hear your thoughts. Let’s start a conversation in the comments!

RAD Basic Team