AL Development with an open-source alternative to VS Code

Did you know that you can do AL development in the open-source version of VS Code, VSCodium, check out the video:

https://youtu.be/K7Af5upUbA4

In this video, Erik explores whether you can do AL development for Business Central using VSCodium — a fully open-source alternative to Visual Studio Code. He walks through the installation process, installs the AL Language extension, creates a project, downloads symbols, builds, deploys, and even tests the debugger. Spoiler: it all works.

What Is VSCodium?

We all love Visual Studio Code — that’s fair to say. But there’s something a little odd about it: while VS Code is marketed as an open-source product from Microsoft, what you actually download and install is not purely the result of that open-source code. The official VS Code distribution includes telemetry, proprietary Microsoft features, and various other bits that aren’t open source.

Enter VSCodium. This project takes the open-source code that Microsoft publishes for VS Code, compiles it cleanly, and distributes it without all the Microsoft-specific additions. The name is a play on the relationship between Chrome and Chromium — VSCodium is to VS Code what Chromium is to Chrome.

The key point Erik emphasizes: this is not a crappy alternative. It’s basically VS Code — but truly open source. And it runs everywhere: Windows, macOS, Linux, even ARM.

Installation

The installation process is straightforward. Erik downloads the 64-bit Windows user setup installer, which comes in at about 80 MB. Since it’s not a signed executable from Microsoft, Windows will warn you — you’ll need to click through “Keep” and “Keep anyway” to proceed.

The installer presents an MIT license (a refreshing change), and it installs into AppData\Local\Programs\VSCodium. Erik opts not to register file types or add it to the PATH during setup. Within moments, VSCodium launches and it looks… exactly like VS Code. The welcome screen even says “Get Started with VS Code.”

The Extension Marketplace Difference

Here’s where the first real difference surfaces. When you open the Extensions panel and search for “AL,” the AL Language extension is nowhere to be found. Searching for popular extensions like Waldo’s CRS AL Language Extension also returns nothing.

This is because VSCodium does not connect to Microsoft’s proprietary Visual Studio Marketplace. Instead, it uses the Open VSX Registry. Many extensions are available there, but the AL Language extension — being a Microsoft-specific extension — is not.

Installing the AL Language Extension Manually

The workaround is simple: install the extension from a .vsix file. If you’re running a Business Central Docker container, you can download the AL Language extension directly from port 8080 on that container. Then in VSCodium:

  1. Click the three-dot menu (...) in the Extensions panel
  2. Select Install from VSIX…
  3. Browse to the downloaded .vsix file

The output window confirms: “Completed installation of AL Language extension.” That was easy.

Creating an AL Project

Erik creates a new AL project targeting a Business Central 20 Docker container. After trusting the workspace folder (as you would in regular VS Code) and entering the server credentials, symbols download successfully.

Here’s the app.json for the test project:

{
  "id": "b684f17c-bdab-4419-b0a0-81b99f3d9948",
  "name": "vscodium",
  "publisher": "Default publisher",
  "version": "1.0.0.0",
  "brief": "",
  "description": "",
  "privacyStatement": "",
  "EULA": "",
  "help": "",
  "url": "",
  "logo": "",
  "dependencies": [],
  "screenshots": [],
  "platform": "1.0.0.0",
  "application": "20.0.0.0",
  "idRanges": [
    {
      "from": 50100,
      "to": 50149
    }
  ],
  "resourceExposurePolicy": {
    "allowDebugging": true,
    "allowDownloadingSource": false,
    "includeSourceInSymbolFile": false
  },
  "runtime": "9.0"
}

Building, Deploying, and Debugging

Erik writes a simple page extension to test the full development workflow:

pageextension 50100 CustomerListExt extends "Customer List"
{
    trigger OnOpenPage()
    var
        x: Integer;
        y: Text;
    begin
        x := 45;
        y := format(X);
        Message('App published from VSCodium: Hello world');
    end;
}

The results:

  • Build: Works perfectly. Ctrl+Shift+B compiles without issues.
  • Deploy: Pressing F5 deploys to the Docker container, logs in, and publishes the app — no questions asked.
  • Debugging: Setting a breakpoint and running the debugger works as expected. Variables are visible, stepping through code functions normally. The full debugging experience is intact.

Everything works in a boringly identical fashion to regular VS Code — which is exactly the point.

Why Consider VSCodium?

There are several reasons you might want to give VSCodium a try:

  • True open source: You know exactly what’s running on your machine, with no proprietary telemetry or Microsoft services baked in.
  • Performance: An interesting open question — without Microsoft’s additional features and services, could VSCodium be faster? Erik is curious whether developers with huge AL solutions might notice a difference.
  • Philosophy: If running genuinely open-source software matters to you, VSCodium lets you do AL development without compromise.

Potential Caveats

There are a few things to be aware of:

  • Extensions from Microsoft’s Marketplace won’t appear in VSCodium’s extension search — you’ll need to install them manually via .vsix files.
  • Some extensions that depend on proprietary Microsoft APIs might not work.
  • You may see occasional minor differences, like a “extensions modified on disk” reload prompt that Erik noticed but doesn’t recall seeing in regular VS Code.

Conclusion

VSCodium is a legitimate, fully functional alternative to VS Code for AL development. Erik was able to install the AL Language extension, create a project, download symbols, build, deploy, and debug — the entire development workflow — without any real issues. It’s the safe way to be a rebel. If you value knowing exactly what’s running on your machine, or if you’re simply curious whether shedding Microsoft’s additional layer makes a difference for large AL solutions, VSCodium is well worth a try.

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