From Numbers to Narrative
Session replay takes analytics from numbers to narrative. Instead of knowing that 40% of users abandon a form, you can watch exactly what confused them.
How It Works
Session replay does not record video of the user's screen. Instead, it captures a stream of DOM mutations, mouse movements, scroll positions, clicks, and input events. On playback, it reconstructs the DOM state at each point in time, creating a faithful recreation of what the user saw and did.
The data format is a JSON stream of events, typically 100–500KB per session depending on page complexity and session length. This is far smaller than screen capture video would be. Though some folks will make movies from this data anyway.
| Aspect | Detail |
|---|---|
| How it works | Captures DOM mutations, mouse movement, scroll, clicks, inputs as JSON events |
| Data format | JSON event stream, ~100–500KB per session |
| Sensitive data | Must mask passwords, PII, payment fields — best tools mask by default |
| Privacy | Requires explicit user consent under GDPR; must be disclosed in privacy policy |
| Value | Qualitative insight — see exactly what confused users experienced |
| Example tools | rrweb (open source), FullStory, Hotjar, LogRocket |
The Qualitative Leap
The qualitative leap session replay provides is significant: instead of inferring user intent from aggregate numbers, you see exactly what happened. A user hovering over the wrong button, scrolling past the CTA, or rage-clicking a non-interactive element tells a story that no metric can easily capture.
Usability replay capture tools can even be used to capture video of a user to correlate facial tells and even user verbalizations (yes this might include cursing) to provide observational insights beyond the click stream. This approach is not realistic outside the lab, but the few times it has been used, it produced more interesting results than just replay followed by user interviews.