To have direct observation of students during an online programming course is impossible. This makes it harder for teachers to help struggling students. By using an online programming environment we have the opportunity to record what the students actually do to solve an assignment. We can analyse the recordings and provide teachers with valuable information. We developed and used an online programming toolwith fine-grained event logging to observe how our students solve problems. Our tool provides descriptive statistics and accurate replays of a student’s programming sessions, including mouse movements. We used the tool in a course and collected 1028 detailed recordings. We compare fine-grained logging with existing coarsegrained logging solutions to estimate assignment-solving time. We find that time aggregations are improved by including time for active reading and navigation enabled by the increased granularity. We also divide the time users spent into editing (on average 14.8%), active use (on average 37.8%), passive use (on average 29.0%), and also estimate time used for breaks (on average 18.2%).Finally wesee a correlation between early student submission results and students that hand in later, but also see an example where the results differ significantly.