The Dongba script, recognized as a UNESCO Memory of the World in 2003, is considered the world’s last living pictographic writing system but remains critically endangered. In response, the Institut National des Langues et Civilisations Orientales (Inalco), the University of Geneva (Unige), and Beijing Language and Culture University (BLCU) collaboratively developed a MOOC to revitalize the script. Offered in four languages, the course teaches 300 high-frequency Dongba characters and incorporates “graphoculture” to highlight cultural contexts. During its first launch in 2023, the MOOC attracted over 2,000 participants from 80 countries, with 234 earning completion badges. This article examines the course’s design, learner engagement, and its impact on endangered language preservation. It explores whether MOOCs can contribute to revitalizing endangered writing systems and identifies key design factors influencing learner experience. The paper argues that MOOCs can function not only as educational tools but also as research platforms for digital heritage preservation.