Session Replay

Session replay is a technology that records a user's browsing session as a video-like playback, capturing mouse movements, clicks, scrolls, form interactions, and page navigation. It lets you watch exactly what users did on your site, revealing friction points, confusion, and opportunities that aggregate metrics cannot show.

Category: Analytics (also: UX)

Author: Atomic Glue Analytics Team

## Definition

Session replay (also called session recording) is a qualitative analytics tool that records individual user browsing sessions and replays them as a video timeline. The recording captures mouse movements, clicks, taps (on mobile), scroll behavior, form field interactions (keystrokes may be masked for privacy), page navigation, and tab/browser events. Session replay does not actually record video. It reconstructs the page and replays the logged events in sequence, which means it is highly accurate and searchable. Tools like Hotjar, FullStory, Microsoft Clarity, LogRocket, and Smartlook provide session replay functionality. Session replay is used to understand why users abandon forms, find confusing UI elements, validate that tracking implementations work as expected (conversion funnels firing correctly), diagnose error states, and build empathy for the user experience. Unlike heatmaps which show aggregate patterns, session replay shows individual journeys in detail.

## Session replay vs heatmaps

Heatmaps answer 'what' (where do users click collectively). Session replay answers 'why' (what is the user's journey, what confusion did they encounter). A heatmap might show that 40% of users click a non-clickable element. Session replay shows you that those users are clicking it multiple times, hesitating, scrolling up and down in confusion, and then leaving. Use heatmaps to identify problematic pages and session replay to diagnose the specific user experience issues.

## Privacy and consent considerations

Session replay captures detailed user interactions, which raises significant privacy concerns. Regulations like GDPR classify session replay data as personal data. You need: explicit user consent before recording (covered by your cookie consent if recordings are non-essential), masking of sensitive fields (password fields, credit card numbers, personally identifiable information in form fields), the ability to delete recordings on request, and clear privacy policy disclosures. Tools like FullStory and Hotjar offer built-in privacy controls: automatic masking, CSS selectors to hide elements, and IP anonymization.

## Using session replay effectively

Do not watch random sessions. Start with data: use GA4 or heatmaps to identify pages with high exit rates, low conversion rates, or high error rates. Segment by traffic source, device type, or user segment. Watch recordings of users who got stuck, abandoned a form, or encountered an error. Take notes on patterns you observe across multiple recordings (3-5 recordings showing the same issue confirms a pattern, 10+ means it is a systemic problem). Create clips to share with your design and development teams.

## Note

Misconception: session replay records video of the user's screen. It does not. It records events (clicks, scrolls, keystrokes) and reconstructs the page state at each moment. The result looks like a video but is actually a sequence of JavaScript events being replayed. This means it captures exact DOM state, including dynamic content changes. Another misconception: session replay is too expensive for small sites. Microsoft Clarity offers free, unlimited session replay. Hotjar has a free tier for limited recordings.

## Common questions

Q: Is session replay legal under GDPR?

A: Yes, with proper consent and privacy safeguards. You need user consent for recording, must mask sensitive fields, and need the ability to delete recordings on request. Many tools provide built-in compliance features.

Q: Does session replay slow down my website?

A: The recording script is typically loaded asynchronously and has minimal performance impact (usually < 10-20 KB gzipped). The recording happens in the background; replay happens in the tool's interface, not on your site.

Q: How many sessions should I watch?

A: Start with 5-10 recordings from a specific segment (e.g., users who abandoned the checkout page on mobile). If 3-4 show a consistent pattern, you have a finding. For quantitative validation, use heatmaps and analytics.

## Key takeaways

• Session replay shows individual user journeys as reconstructed playback
• Essential for qualitative understanding of user behavior (the 'why' behind the metrics)
• Requires proper privacy controls: consent, data masking, deletion capability
• Use heatmaps to identify pages with issues, then use session replay to diagnose them
• Microsoft Clarity offers free unlimited session replay

## Related entries

• [Heatmap](atomicglue.co/glossary/heatmap)
• [Google Analytics 4 (GA4)](atomicglue.co/glossary/google-analytics-4-ga4)
• [Cookie Consent](atomicglue.co/glossary/cookie-consent)

Last updated July 2026. Permalink: atomicglue.co/glossary/session-replay