Performance Evaluation of Monolithic Architectural Design in Online Ornamental Plant Sales Platform

System architecture design is critical to system construction, with monolithic architecture offering a simple and centralized development pattern. This research examines its application to an online platform selling ornamental plants, integrating several menus into one integrated system. Performance was evaluated through load testing on two types server, namely Linux and Windows using Grafana K6 tools. Quantitative assessment using AHP and MOORA, considering criteria, HTTP failure (HF), P95 response time (RT), peak RPS (PR), and requests made (RM). The results show significant differences between testing on Linux and Windows. Test results on Windows server show reliability of around 40%, while Linux server test results achieve access effectiveness of 90% with an average response time of 2654 ms. Testing on Windows server recorded an average connection time of 1.78 ms and an HTTP failure rate of 2.16%. Testing on Linux server shows better performance with fewer HTTP failures and improved scalability. The complexity of monolithic architectures can cause bottlenecks and maintenance challenges in large-scale systems. These findings provide insight into the reliability and effectiveness of websites, offering implications for system architecture design and performance optimization in similar contexts.