Getting Started with AL

To get started writing extensions for Dynamics 365 Business Central you will need a Business Central tenant, Visual Studio Code, and the AL Language extension. Visual Studio Code is a cross-platform editor that you will use for coding and debugging.

Steps to set up a sandbox environment and Visual Studio Code

Go through the following steps to set up a sandbox environment. With this you get sample code that compiles and runs with just a few commands.


If you want to create a container-based sandbox, see Get started with the Container Sandbox Development Environment. For information about which sandboxes you can choose, see Sandbox Environments for Dynamics 365 Business Central Development.


It is not supported to publish, from Visual Studio Code, an extension with the same identifiers as an extension published to AppSource. Identifiers include the combination of appID and version or name, publisher, and version. If you do publish such an extension, it can be removed at any time.

  1. Sign up for a Dynamics 365 Business Central sandbox.
  2. Download Visual Studio Code.
  3. Download the AL Language extension.
  4. Press Ctrl+Shift+P to open the User Settings window; here you can modify the telemetry settings.
  5. Press Alt+A, Alt+L to trigger the AL Go! command, choose a path to a new empty folder and which version to run. Then choose Microsoft cloud sandbox as the server.


    If you want to change your configuration at a later point in time, you can choose the Add Configuration button on the bottom right side, and then choose one of the available options.

  6. Enter the credentials that you provided for the sign-up.
  7. Press Ctrl+F5 to deploy and run the extension on your online sandbox tenant.

You now have a HelloWorld sample that compiles and runs. The JSON files in the project are automatically updated with the settings that allows you to press Ctrl+F5 to build and deploy the solution to Business Central. For more information, see JSON Files.

Tips and tricks

  • Use Ctrl+Space to activate IntelliSense at any place in the code, which will help you identify possible options.
  • Always use the .al extension on new files.
  • Use the built-in snippets for code by starting typing t and pick from the list.
  • Create objects within the right object ranges, see Object Ranges in Dynamics 365 Business Central.
  • Build and get inspired by our sample library on GitHub.
  • Use Ctrl+Shift+P and select AL: Clear credentials cache to clear the credentials cache if you want to deploy against a different environment.
  • Use F2 to rename objects, types etc. For more information, see Keyboard Shortcuts.

JSON file settings

There are three JSON files in the project; the app.json file, the launch.json file, and the rad.json. The files are automatically generated for your project. For more information, see JSON files and Working with Rapid Application Development (RAD).

AL configuration settings

Use the AL configuration settings to specify general preferences for working with AL projects. For more information, see AL Language Extension Configuration.

Telemetry settings

By default, Visual Studio Code is set up with a telemetry system to enable that data and errors are sent to Microsoft. If you do not want to send telemetry data, you can change the telemetry.enableTelemetry setting from true to false.

To modify the telemetry setting, press Ctrl+Shift+P in Visual Studio Code and choose User Settings, which opens the settings.json file, and then add telemetry.enableTelemetry and set it to false like shown below.

"telemetry.enableTelemetry": false,


The settings.json file contains user and workspace settings, these options can be modified to suit your preference. If you want to modify Visual Studio Code editor options and functional behavior settings, see User and Workspace Settings.

Installing and publishing an extension

To make your extension available to users, the package must be published to a specific Business Central server instance. The extension can be installed for one or more tenants. For more information about how to install and publish an extension, see How to: Publish and Install an Extension.

Controlling user access to developing and publishing extensions

The access to developing and publishing extensions is controlled on a user or user group basis by the EXTEND. MGT. - ADMIN permission set. It is important that the EXTEND. MGT. - ADMIN isn't specified for a specific company, but left blank.

If you add new permission sets and want to control the access to developing and publishing extensions, you must include indirect read and write permissions to the Published Application table (read – for downloading symbols, write – for publishing the app) in the permission set.

To prohibit a user from publishing, just remove the user from the EXTEND. MGT. - ADMIN permission set.


The EXTEND. MGT. - ADMIN permission set was introduced in Business Central 2021 release wave 1 as a replacement for the D365 EXTENSION MGT permission set in earlier versions.

Next steps

Now that you have the tools and the HelloWorld example up and running, you might want to try to create a small sample app in AL. This walkthrough guides you through how to create a simple app adding objects, code, and publishing the app to your tenant. For more information, see Building Your First Sample Extension With Extension Objects, Install Code, and Upgrade Code.

See Also

AL Development Environment
FAQ for Developing in AL
Building Your First Sample Extension With Extension Objects, Install Code, and Upgrade Code
AL Language Extension Configuration
XML Comments in Code