Rapid technological advances have benefited education in many ways, giving rise to what is now called "educational technology." Technology is also improving in education practices. Education in Indonesia must be able to innovate and utilize this technology to benefit learning. There are numerous mobile programs that can be utilized as learning resources, one of which is the Duolingo app.  The purpose of this study is to determine whether or not there is a correlation between students' Duolingo XP and vocabulary mastery. The research was conducted on eighth-class students in SMP Negeri 9 Banjarmasin 2023/2024.

This research used correlation analysis. The instruments to collect the data were observation and tests on vocabulary mastery in multiple choice form. Each of the data collected was analyzed by using Pearson Product Moment correlation. The findings revealed a coefficient correlation of 0.262 with a significance level of 0.047.  It represents a low correlation between two variables.  Using hypothesis testing, the significance threshold was less than 0.05.  It signifies that the hypothesis has been accepted.  As a result, there appears to be a low positive correlation between students' Duolingo XP and their vocabulary competence.

Based on the findings, it can be concluded that the amount of XP they earn in Duolingo is relate on their vocabulary mastery. The more students learn English on Duolingo, the more newly vocabulary the get. This findings is suggested that students be more enthusiastic about learning English and should have more practice acquiring the English vocabulary through any media such as Duolingo. By considering vocabulary mastery, students might become more prepared to take on any materials regarding English skills.