This research aimed to develop a web-based application for teacher candidate competence instruments to prepare professional teachers in the Industrial Revolution 4.0 (IR 4.0) era. Teacher candidate competencies consist of pedagogical, professional, social, and personality competences. This is a research and development with 8 stages, involving the development of instrument grids/ construct, focus group discussions, instrument item development, instrument validation, manual instrument testing, application development, application assessment by experts, application trial, and final revision of the application. The initial focus group discussions involved 9 experts, while the instrument validation involved 35 experts consisting of 21 experts for pedagogical and professional competences, 7 experts for social competences, 7 experts for the personality competences, and 4 media experts. The trial involved a total of 107 Mathematics, Indonesian, and English student teacher candidates. Expert validation was analyzed using the Aiken formula; application effectiveness and readability were described based on expert judgment, and discrimination tests on the results of social and personality competence tests between the study programs used the Multivariate Analysis of Variants. The results showed that there were no differences in social and personality competences between Mathematics, Indonesian, and English prospective teachers. The developed instruments for pedagogical, professional, personality, and social competences were deemed valid. The application has met the readability aspect and is scored well by experts with an average assessment rating of .78. These results suggest that the application can be used by the government as a solution to assess teacher candidate competences in the IR 4.0 era.