If you’re new to Dynamics 365 Business Central development, AL is the first thing you need to learn. It’s the programming language used to build extensions, customize pages, and add business logic to BC.
What is AL?
AL (Application Language) replaced the old C/AL language with the move to Business Central. It’s a modern, object-based language designed specifically for business application development within the Microsoft Dynamics 365 ecosystem.
Setting Up Your Development Environment
Before writing any code, you need:
- Visual Studio Code — the primary IDE for AL development
- AL Language extension — install it from the VS Code marketplace
- Business Central sandbox — a cloud or Docker-based environment to test your code
Installing the AL Extension
Open VS Code, go to Extensions, and search for “AL Language”. Install the official Microsoft extension. Once installed, you can create a new AL project using the command palette:
AL: Go! → select your BC version → enter your sandbox URLYour First AL Extension
Let’s create a simple extension that adds a custom field to the Customer Card.
tableextension 50100 CustomerExtension extends Customer
{
fields
{
field(50100; "Loyalty Points"; Integer)
{
Caption = 'Loyalty Points';
DataClassification = CustomerContent;
}
}
}
pageextension 50100 CustomerCardExtension extends "Customer Card"
{
layout
{
addafter("Phone No.")
{
field("Loyalty Points"; Rec."Loyalty Points")
{
ApplicationArea = All;
ToolTip = 'Specifies the loyalty points for this customer.';
}
}
}
}This extension does two things:
- Adds a new
Loyalty Pointsfield to the Customer table - Displays it on the Customer Card page, right after the phone number
Building and Deploying
Press Ctrl+Shift+B to build your extension, then F5 to deploy it to your sandbox. BC will restart the web client with your extension loaded.
Key Concepts to Learn Next
- Events and Subscribers — hook into existing BC processes
- Reports — create custom reports with AL
- APIs — expose BC data through custom API pages
- Permissions — control access to your custom objects
Summary
AL development opens up the full power of Business Central customization. Start small with table and page extensions, then gradually explore more advanced patterns like codeunits, events, and integrations.
The best way to learn is to build. Pick a real business requirement and try to implement it — that’s how real skills are built.