MatomoCamp 2025

HyperLogLog to estimate uniqueVisitors for non-day periods in Matomo
11-26, 14:00–14:30 (Europe/Madrid), Room 1

For non-day periods unique visitors are not unique in Matomo, they are basically sum of unique visitors. HyperLogLog solves this issue by using a probabilistic algorithm to estimate unique values in large dataset.


  • Explain unique visitor issue
  • Why we can't calculate unique visitors for non-day periods
  • How HyperLoglog helps
  • What was the performance impact on AbTesting plugin, when we enabled it.
  • Possible usecases in Matomo

An engineer with over 11 years of experience in tech, currently serving as a Senior Software Engineer at InnoCraft. In my role, I contribute to the development of plugins in Matomo Analytics, a widely used open-source analytics solution championing user privacy and data ownership.