Extensibility home page

Dynamics 365 Finance, Supply Chain, and Commerce are extensively customized by partners, value added resellers (VARs), and even some customers. The ability to customize the product is a strength that has historically been supported through overlayering of the application code. The move to the cloud, together with more agile servicing and frequent updates, requires a less intrusive customization model, so that updates are less likely to affect custom solutions. This new model is called extensibility and has replaced customization through overlayering.

Extensibility is the only customization framework in Finance, Supply Chain, and Commerce. Overlayering isn't supported.


These introductory topics contain general information about customization. This information includes information about when the transition occurs from customization through overlayering to a purely extension-based model. These topics also explain how to log extensibility requests to Microsoft, and provide answers to frequently asked questions (FAQ).

What's new

Read What's new or changed for extensibility for extensibility-related updates that have been made since July 2017.

Getting started

The topics in this section will help you start to build extensions. They will also help you migrate solutions that are currently based on overlayered code to extension-based solutions. This section includes hands-on labs that walk you through simple customizations.

Fundamentals on extensions

This section includes fundamentals, principles, and practices for making extensions. The guiding principles in these topics discuss how customization must be approached through extensions. These principles include naming guidelines. Additionally, these topics discuss the foundation framework, such as extensions and chain of command.

How do I create extensions?

This section includes "How do I?" topics that explain how to customize specific object types or code. Most of these topics are brief and to the point. Because there are many topics here, it might be practical to search for a specific article.

Data types






Blog posts

Information about customization is also shared through blogs where various topics are discussed. This section includes reference to some of these blogs.

How do I create an extensible solution?

This section includes some best practices on how to create/make your solution extensible, so that consumers of your code can extend your solution.

Breaking changes

When you make your solution extensible, you also help guarantee that you won't break those extension points later.

  • For pointers that can help you avoid breaking your consumers, see Breaking changes.
  • The compatibility checker tool can detect metadata breaking changes against a given baseline release or update, helping to ensure backward compatibility.