This study investigates students' evaluations of the effects of using a website builder-based project (WBP) on learning English for Specific Purposes (Legal English), specifically in relation to reflection, collaboration and skills development. The study also examines how WBP affects student learning motivation and academic achievement, as well as students' beliefs about the feasibility and potential of using WBP in learning. The study employs mixed-method design that includes qualitative and quantitative approaches. Three hundred and three second-year students, who enrolled in the Legal English course at a university in Vietnam participated in the study, basing on the stratified sampling. The main instruments include questionnaires followed by the open-ended questions, and interviews. The findings demonstrate that WBP had a positive impact on students' collaboration, reflection and skills development. Additionally, the use of WBP significantly influenced students' academic achievement, and there was a slight difference in academic achievement between the group using WBP and the group without WBP use. Students acknowledged that using WBP in learning is a feasible, innovative and potential approach for both present and lifelong learning. The changes in teaching and learning approaches by teachers should be made to be compatible with this innovation in a smart educational environment.