The increasing development of technology has now made it easier to carry out building shop sales transactions. CV Mitra Mandiri is a company operating in the clean water company sector which sees an opportunity to develop an online building shop sales system. Here the author provides a solution using a web-based application and to make this happen. the. So the purpose of this writing is to design
and build a web-based application with the CodeIgniter framework, method using waterfall and a database using the MYSQL database. Programming language using PHP. The design includes Use Case Diagrams, Activity Diagrams, class diagrams. Testing the application using the Black Box testing method, functionally has been declared successful. And based on test results using the System Usability Scale
(SUS), a score of 78,77 has been obtained with a value above average so that it can be accepted by users.
Keyword : Online building shop, Codeigniter, PHP programming language, Sus