
The SAP Extensibility Explorer documents some of the most commonly used patterns in extension development. Both in-app and side-by-side extension patterns are covered. In this lesson we will explore several.

This is a common pattern for all the other side-by-side patterns and can be used for:
- Common "dependent extension" use cases:
Proxy applications: Create highly connected applications and shield your SAP S/4HANA Cloud system from the Internet.
Convenience application: Optimize SAP S/4HANA Cloud by simplifying and specializing the user experience.
Preprocessing application: Collect data before a process is started in the SAP S/4HANA Cloud system.
Postprocessing application: React to events from your SAP S/4HANA Cloud system after certain process steps are completed and perform additional activities on SCP.
- Common "custom application" use cases:
New applications: Implement new apps with or without SAP S/4HANA Cloud (including mobile applications).
Analytical applications: Connect data from multiple sources to one analytical database.
Substitute applications: Replace a specific process or process step in SAP S/4HANA Cloud.
- Common "custom application" use cases:
- New applications: Implement new apps with or without SAP S/4HANA Cloud (including mobile applications).
- Substitute applications: Replace a specific process or process step in SAP S/4HANA Cloud.
- Analytical applications: Connect data from multiple sources to one analytical database.

You can use the user interface integration pattern to create new UIs as part of the custom application by consuming the processes integrated using SAP S/4HANA Cloud APIs. Some of the sample applications in the SAP Extensibility Explorer making use of this pattern are:
SAP S/4HANA Cloud Product Web Ordering and Reporting (Consuming and updating SAP S/4HANA data within an external (B2C) application).
Display SAP S/4HANA Cloud Products on an iOS Device (Native iOS app to display products from SAP S/4HANA).
Timesheet Data Export (Create a side-by-side application to export timesheet data to Microsoft Excel or print it as a PDF document).

You can use the process integration pattern to create new processes in the custom application by consuming the released APIs exposed by SAP S/4HANA Cloud. Some of the sample applications in the SAP Extensibility Explorer making use of this pattern are:
Display Created or Changed Sales Orders Using Business Event Handling (Create a side-by-side app on SAP Business Technology Platform that consumes business events from SAP S/4HANA Cloud).
Migrated Sales Order Data (Create a side-by-side application to perform search, sort, and filter operations on historical sales order data migrated from a legacy system).
Quick Time Entry for SAP S/4HANA Cloud Time Recording (Create a side-by-side app for faster time recording using the SAP S/4HANA Cloud SDK).

You can use the events integration pattern to:
Support event-driven architecture.
Enable easy asynchronous app-to-app communication.
Subscribe to business events using self-service configuration in SAP S/4HANA Cloud and consume them through SAP Business Technology Platform Enterprise Messaging and Enterprise Event Management in extension applications built by a customer or partner.
Some of the sample applications in the SAP Extensibility Explorer making use of this pattern are:
Display Created or Changed Sales Orders Using Business Event Handling (Create a side-by-side app on SAP Business Technology Platform that consumes business events from SAP S/4HANA Cloud).
Situation Handling Automation (Trigger purchase contract changes and assign the supplier in a purchase requisition based on defined business rules).

You can use the Data Integration pattern to:
Replicate released CDS Views along with the underlying tables and data from an SAP S/4HANA Cloud source system to an SAP Business Technology Platform target system.
Get full data availability, near real-time replication, and data consistency.
Enabled mass data replication.
A sample application in the SAP Extensibility Explorer making use of this pattern is Replicate CDS Views (Replicate CDS Views in SAP S/4HANA, including the underlying tables and data, to target SAP Business Technology Platform systems).

You can use the Rules and Workflow pattern to:
Empower users to manage business logic independently from application development.
Ease developers' use and management of rules with REST APIs.
Rapidly build decision logic for workflow and extension apps on SAP Business Technology Platform.
Some of the sample applications in the SAP Extensibility Explorer making use of this pattern are:
Situation Handling Automation (Trigger purchase contract changes and assign the supplier in a purchase requisition based on defined business rules).
Change Payment Information Through Approval Workflow (Create a workflow application that allows users to change a business partner's payment information through an approval workflow).

You can use the User Integration pattern to:
Understand different authentication methods when connecting an SAP Business Technology Platform Neo account to your SAP S/4HANA Cloud: Basic, Client Certificate, or (OAuth) SAML Bearer Assertion.
Understand the use of SAP Business Technology Platform Identity Authentication Service.
Some of the sample applications in the SAP Extensibility Explorer making use of this pattern are:
Set Up Authentication for SAP S/4HANA Cloud Extensions (Set up the connectivity from SAP Business Technology Platform to your SAP S/4HANA Cloud tenant using different authentication types).
Manage Approval Documents from SAP Ariba (Fetch approval documents (invoices & purchase requisitions) via a chatbot).