Data gaps in GA4 are like missing pieces of a puzzle. They usually happen when a user’s journey is interrupted—for example, when they move from a social media app to your website, or when they switch from a phone to a laptop.

A server-side tracking solution acts as the “glue” that holds these pieces together. By collecting data on the server, you can “stitch” different sessions together more effectively. This fills in the gaps, allowing you to see a continuous story of how a user went from seeing an ad to becoming a loyal customer, without the confusing breaks in the data that standard tracking often has.