## 4.2.14.1  Developing and Operating SaaS Applications
Learn how to develop and operate SaaS applications by using add-ons in the ABAP environment.
## Introduction
The ABAP environment allows you to leverage existing ABAP know-how to create custom add-ons in the cloud. This add-on build process is orchestrated by using the ABAP environment. Delivery tools, such as the Add-on Assembly Kit as a Service for the registration and publishing of the add-on as a software product, and deployment tools to carry out test installations and to make the add-on available for productive use, simplify this process. See Delivery Tools and Deployment Tools .
##  Note
You should only consider using add-on delivery if you intend to offer a Software as a Service (SaaS) solution.
##  Note
Note that only one add-on can be installed per system.
Following the add-on build process, you can develop a multitenant application to share the add-on with multiple consumers (tenants) simultaneously. See Multitenant Applications [page 1248]. The application is registered with the Software-as-a-Service provisioning service (saas-registry) to make the application available for subscription to consumers. See Register the Multitenant Application to the SaaS Provisioning Service.
In this context, the ABAP Solution Service [page 1251] accounts for the provisioning of new ABAP service instances, including the installation of the add-on, and the creation of tenants whenever required for a new consumer subscription.
The way ABAP service instances and tenants are used for consumer subscription applications can be configured as follows:
- Single-tenant enabled : With each new consumer, a new ABAP service instance is created
- Multi-tenant enabled : For multiple consumers, the same ABAP service instance is used
For more information, see Multitenancy in the ABAP Environment.
## What Is This Guide About?
This guide describes the end-to-end process of developing and offering a SaaS solution using the ABAP environment. The following chapters cover all aspects of this scenario, from the initial setup and development tasks to the final productive use by consumers.
The Concepts [page 1192] chapter gives you an overview about important concepts that are relevant throughout the end-to-end process.
The Glossary [page 1187] contains a list of all the technical terms and phrases used in this scenario.
Chapter Develop, Test, Build [page 1219] describes the actual development activities. This includes the setup of the required account structure and system landscape, as well as the recommended testing process and subsequent build of the add-on.
Chapter Order and Provide [page 1244] illustrates how a developed add-on can be deployed and made available to consumers. It also shows how consumers order solutions and what steps you, as the provider, need to perform to provision the solution.
Chapter Configure and Implement a Customer Project [page 1267] describes how to configure and implement a customer project in the consumer tenant, including the setup of identity and authentication management, integration with other systems or services, and adjustment of business configuration.
Chapter Maintain, Monitor, Support [page 1270] gives you an overview about the activities involved in maintaining an already commercialized product, as you usually continue to support the add-on, fix bugs, and potentially offer new functionalities as time goes on.
Chapter Dismantle [page 1279] provides information about consumer offboarding, in particular about deleting and restoring tenants.
##  Note
If you decide to use gCTS transport instead of add-on delivery, please refer to the gCTS Delivery boxes across the guide. See Delivery via Add-On or gCTS [page 1214].
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- Prepare [page 1220]
- Develop [page 1232]
- Test [page 1235]
- Build [page 1238]
- Deploy [page 1244]
- Commercialize [page 1264]
- Subscribe [page 1265]
- Subscribe [page 1265]
- Maintain, Monitor, Support [page 1270]
- Order and Provide [page 1244]
- Develop, Test, Build [page 1219]
- Configure and Implement a Customer Project [page 1267]
- Maintain [page 1270]
- Troubleshoot and Debug [page 1278]
- Dismantle [page 1279]
For more information, see Build ABAP Code into an Add-on Product and Make it Available as a Tenant-Aware SaaS Solution .
##  Caution
The tutorial group "Convert Your Add-on Product into a Tenant-aware SaaS Solution" is now replaced by the functionality of the Maintain Solution app.