Many things in the world share similarities, yet variations still exist. The same applies to software development, where commonalities and differences are present. In this regard, the productivity of software development can be improved by applying software product line engineering (SPLE). One challenge in applying SPLE is managing architectural variations in development and deployment, such as microservices. Microservices split an application into separately deployable services that may communicate internally. However, these internal communications can hinder systematic interchangeability, reducing flexibility within the product line. We propose a refined solution based on Unified Modeling Language (UML) with extension for delta oriented programming (DOP) to address challenges in re-engineering microservice-based webshops into software product lines (SPL). Our approach defines a mechanism to reengineer microservices and generate a web-based SPL, designed to support the generation of independent services. We generate a running web application with Java backend and React frontend application. From a single SPL code base, we successfully produce four of the six selected cases of microservice-based webshops. © 2025 Copyright held by the owner/author(s). Publication rights licensed to ACM.