---
id: topic/dev-itpro/development/extensibility/developing-client-add-ins
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title: Developing client add-ins
summary: Developing client add-ins covers guidance for building control add-ins in Business Central. It answers questions about performance practices, such as AL trigger invocation, callbacks and payload size, and about visual styling, such as colors, typography and CSS.
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    - post/jpearson-blog/1601
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  - Developing client add-ins
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---

# Developing client add-ins

> Developing client add-ins covers guidance for building control add-ins in Business Central. It answers questions about performance practices, such as AL trigger invocation, callbacks and payload size, and about visual styling, such as colors, typography and CSS.

Path: [Development](../../development.md) > [Extensibility](../extensibility.md) > Developing client add-ins · tier official · system development · narrative reviewed (checked by Opus)

## Overview

This section has two pages for developers who build control add-ins that run in the Business Central client. One page covers how an add-in should behave at runtime. The other covers how it should look.

The performance page explains how to call AL triggers and handle callbacks, and how to keep payloads small. Poor performance can lead to reduced functionality warnings and request throttling. The style guide gives the CSS color palette, typography, font families, chart colors and design principles. Following it helps an add-in blend into the client with consistent theming and accessibility.

Start with the performance page to avoid throttling and warnings, then use the style guide while you design the add-in's interface. The pages do not depend on each other, so read them in either order.

## Key points

- Invoke AL triggers only after previous calls have completed.
- Avoid excessive payloads when passing data between the add-in and AL.
- Poor add-in performance can trigger reduced functionality warnings and request throttling.
- The performance page covers callback handling, payload optimization, performance monitoring and error handling.
- The style guide defines the color palette, typography and font families for add-ins.
- The style guide includes chart colors and CSS styling guidance.
- Design principles in the style guide aim for consistent theming and accessibility within Business Central.

## Learn pages

- [Control add-in performance best practices](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-control-addin-bestpractices): Learn how to provide the best possible experience and performance for control add-ins in Business Central.
- [Control Add-in Style Guide](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/devenv-control-addin-style): Learn about the style guide for control add-ins in Dynamics 365 Finance.

## Videos and posts

Linked by a Haiku matcher with a grounding quote from the item's summary (link/topics.ts); machine-generated.

- [Step-by-Step Guide to Custom User Controls in Business Central](../../../../posts/aardvarklabs-blog/3680.md) (community post): "Custom user controls in Business Central use HTML, JavaScript, and AL to create bespoke UI components"
- [📊 Mermaid Diagrams in Business Central: Dynamic Visual Intelligence 🎨](../../../../posts/gerardorenteria-blog/12801.md) (community post): "a JavaScript control add-in bridge, and the Mermaid.js CDN"
- [Tip – Access the Clipboard with Business Central](../../../../posts/jpearson-blog/1425.md) (community post): "WebPageViewer control add-in can display HTML and JavaScript for lightweight UI enhancements"
- [Embed Visual Studio Code in Business Central](../../../../posts/jpearson-blog/1583.md) (community post): "Embedding Visual Studio Code's Monaco editor in a Business Central control add-in"
- [Integration with Azure Static Web Apps from Business Central](../../../../posts/jpearson-blog/1601.md) (community post): "WebPageViewer control add-in shows hosted web content inside an iframe"

Source: Microsoft Learn (CC BY 4.0). Descriptions are Learn's own.