Learn AL by writing AL.

Practice problems for Business Central developers. Open one in your browser and start typing — no Docker container, no sandbox tenant, no server installation.

Browse problems See a sample problem

CustomerBalance.al

Running tests… 531 ms

304

Practice problems, from quick warm-ups to genuinely hard ones.

BC 28.4

A real AL compiler — your code builds against the latest Business Central.

Free to start — no card required. Upgrade only for the premium set.

Inside the editor

AL editor in your browser.

Work in a familiar VS Code-style editor: compile, run tests, and learn.

HOW IT WORKS

Three steps. No setup.

Pick a problem

Browse by topic, difficulty. Every problem comes with a clear statement, examples, and what to watch for.

Write code

Solve in your browser. Hints appear when you need them — they nudge, they don't spoil.

Run the tests

See what passes, read the walkthrough, and learn why it works — not just that it does.

WHAT YOU’LL PRACTICE

The AL patterns worth learning.

Each topic ladders up from simple exercises to harder ones, so the fundamentals stick before the tricky parts arrive.

Algorithm

69 problems

Logic puzzles, parsing, transforms, deduplication.

Basics

84 problems

First steps — table and page extensions, fields, enums, simple triggers.

Error-handling

18 problems

TryFunction, ErrorInfo, and collecting errors instead of failing fast.

Extensibility

24 problems

Integration events, subscribers, and interfaces bound to enums.

Filtering

27 problems

Develop your skills in filtering and database queries.

Integrations

37 problems

HTTP client, Rest client, JSON, OData, web services.

Performance

20 problems

Solve problems with a focus on performance.

Transactions

25 problems

Posting, transactional consistency, locking, and much more.