ABSTRACT As digital technology transforms education, investigating shifts in teachers’ formative assessment practices within digital contexts becomes essential. This study explores upper secondary school teachers’ experiences in an 18-month professional development intervention focused on formative assessment in digital contexts. Data from a baseline survey (n = 26) and reflection logs (n = 12) were analysed using descriptive statistics and thematic analysis. Teachers exhibited a preference to provide digital feedback for student learning but expressed uncertainty about its effectiveness. Thematic analysis revealed four main themes: the importance of a shared language for formative assessment; challenges tied to real-time distance learning; the paradoxical nature of digital feedback in fostering dialogue; and strategies for seeking and improving digital feedback. The professional development intervention enhanced teachers’ understanding of formative assessment, including its timing and impact on student learning. The study contributes to the discourse on digital formative assessment, offering insights for educational practices and research.