Abstract: The subject of this research, which is dedicated to testing the digital app “Calligraphy.rus – Learning to Write Letters” for teaching calligraphy to elementary school students, is the quality, effectiveness and convenience of using this educational app in working with elementary school students. The object of this research is the assessments and opinions of elementary school teachers acquired in the course of testing of this app. Testing involved over 400 pedagogues from more than 30 Russian regions; it was conducted based on the method of situation modeling of using digital app in practice, as well as the survey technique. The scientific novelty lies in obtaining objective assessments on the practical effectiveness of modern digital educational resource in the format of digital app for teaching skills of calligraphic writing to elementary school students. The conclusion is made on the high functional capacity of the indicated digital resource based on the assessment given by the pedagogues on such parameters as convenience, design and characters, ease of understanding, task description and feedback. The pedagogues consider this digital app as a promising instrument to be implemented in the educational process and extracurricular activities.