Receiving adequate pronunciation feedback is an ongoing challenge for L2 learners. Although instructors are the most important source of corrective pronunciation feedback (Szpyra, 2014; Timson, 2007), L2 learners can also benefit from peer pronunciation feedback (Lord, 2008; Kim & Yoon, 2014; Roccamo, 2015). This paper examines Japanese university students' perceptions of online peer feedback on intelligibility (Derwing & Munro, 2005). To aggregate the feedback, P-Check, a plug-in for the Glexa LMS (Version2, 2015) was developed and its recognition and dialog functions were piloted in two studies. In the first exploratory study (N = 59), a post-treatment survey and diaries were used to explore participants' attitudes. Participants believed that peer feedback through P-Check was useful and had increased their awareness of their pronunciation strengths and weaknesses. In the second quasi-experimental study (N = 55), no significant difference was found in participants' perceptions of the usefulness of peer feedback, whether delivered face-to-face or via P-Check. Recommendations for further development of P-Check and other similar plug-ins are given.