How do I develop a custom journey builder activity in Salesforce Marketing Cloud?

You can reference the marketing cloud official document. However the documentation is not well organized or presented as other standard Salesforce products documents.

The other option is to read the book “Programming Salesforce Marketing Cloud” https:// marketingclouds.co and it is available to purchase on Amazon: https:// www. Amazon. com/dp/B07QHF4117

This book introduces concepts to integrate with marketing cloud using API and build custom components in a platform agnostic way. These concepts will be applicable to any programming language and platform. If you are not using other Salesforce services, you can apply these concepts in Java, .NET, PHP or any other technilogies. After introducing the concepts, we will implement these concepts using APEX programming language within Salesforce sale cloud. Tips, patterns and special considerations will be introduced when using APEX in sales cloud to implement these concepts, for example:

Java

how to serve custom activity configuration file;

how to expose less REST service and write less APEX class and at the same time achieve right level of encapsulation;

how to decode JWT passing from marketing cloud Journey Builder;

how to build user interface and allow marketing cloud users without sales cloud account to access;

how to display visualforce page inside marketing cloud iframes

how to set up the right architecture.

We will cover the following topics on marketing cloud integration and custom components:

Marketing Cloud Package

Custom Journey Builder Activity

API Integration (Server to Server & Web App)

Custom Marketing Cloud App

Server Side JavaScript