What Is Session Replay? How It Works and Why It Matters

Session replay is a recording of a real visitor's interaction with your website, played back as a video. Instead of guessing what someone did between landing and leaving, you watch exactly where they clicked, scrolled, hesitated, and gave up.

Analytics dashboards tell you what happened — 40% of visitors leave the pricing page. Session replay tells you why — they scrolled past the plan comparison table, hovered over the enterprise button, then closed the tab after the contact form loaded slowly.

How Session Replay Works

When session replay is enabled on a site, a lightweight script captures changes to the page's DOM (the structure of the HTML), along with mouse movements, clicks, scroll position, and form interactions. This data is sent to the analytics server as a stream of timestamped events — not as a video file.

During playback, the tool reconstructs the page using those events, rebuilding each frame from the recorded DOM mutations. The result looks like a screen recording, but it's a reconstruction, not a pixel-by-pixel capture. This keeps the data small (typically a few hundred kilobytes per session) and avoids the bandwidth costs of actual video.

Most session replay tools capture:

• Mouse movement and clicks — where the cursor went, what was clicked, and whether the click triggered a response.
• Scroll depth — how far down a page the visitor reached.
• Form interactions — which fields were focused, how long each took, and whether the form was submitted.
• Page transitions — the sequence of pages visited and how long each took to load.
• Viewport and device info — screen size, browser, and whether the visit was on mobile or desktop.

What Session Replay Shows You

The value of replay is in the patterns you would never spot in aggregate data.

Form abandonment. A visitor fills in three fields of a signup form, pauses on the phone number field for ten seconds, then leaves. One session is anecdotal. Twenty sessions showing the same hesitation on the same field tells you to make it optional.

Rage clicks. A visitor clicks a button five times in quick succession. The button probably looks interactive but isn't responding — a broken link, a loading state without feedback, or a click target that's too small on mobile.

Unexpected navigation paths. You designed the funnel as homepage → features → pricing → signup. Replay shows visitors going homepage → pricing → features → pricing → blog → leave. Your assumptions about the buyer journey might be wrong.

Broken layouts. A CSS issue makes the checkout button invisible on certain screen sizes. Your tests passed on desktop. Replay shows mobile visitors scrolling past it.

Session Replay vs Heatmaps

Session replay and heatmaps answer different questions. They overlap but are not interchangeable.

| | Session Replay | Heatmaps | |---|---|---| | Shows | Individual visit as a timeline | Aggregate behavior across many visits | | Best for | Diagnosing specific problems | Spotting broad patterns | | Granularity | One visitor at a time | Hundreds or thousands of visits combined | | Time investment | Higher — you watch sessions | Lower — you read a visual summary | | Use when | You know where the problem is and need to understand why | You don't know where to look yet |

Start with heatmaps to find the pages and areas that deserve attention, then use replay on those specific flows to understand what's happening.

Privacy Considerations

Session replay captures real user behavior, which means it can also capture sensitive data. Responsible implementations address this with:

• Text masking. Input fields containing passwords, credit card numbers, emails, and other personal data are replaced with placeholder characters before the data ever leaves the browser.
• Element exclusion. Entire page sections (like account settings or payment forms) can be excluded from recording.
• Consent. If your site uses a cookie consent banner, session replay should respect the visitor's choice. Privacy-focused tools let you start recording only after consent is granted.
• Data retention limits. Recordings are automatically deleted after a set period, typically 30 to 90 days.

Under GDPR and similar regulations, session replay data is personal data. Make sure your tool stores recordings in a jurisdiction that matches your compliance requirements and that your privacy policy mentions session recording.

Common Mistakes with Session Replay

Watching random sessions. With thousands of recordings, watching them one by one is a waste of time. Filter by sessions that hit a specific page, triggered an error, or came from a particular traffic source. Look for patterns, not entertainment.

Ignoring mobile sessions. Desktop recordings are easier to watch, but if half your traffic is mobile, skipping those sessions means missing the problems that affect the most visitors.

Not connecting replay to analytics. Replay is most powerful when you can jump from a metric — like a drop in funnel conversion — directly to the sessions that contributed to the drop. Tools that isolate replay from analytics data lose this connection.

Recording everything forever. Storage costs add up. Record the pages and flows that matter to your business, not the entire site by default.

How to Get Started

If you're evaluating session replay tools, consider whether you want it bundled with your analytics or as a separate product. Standalone replay tools like Hotjar and Microsoft Clarity focus on recordings and heatmaps. Platforms like Trfyx include session replay alongside web analytics, funnels, and revenue tracking in a single dashboard — one script tag, one set of data, one place to look.

Trfyx includes session replay on every paid plan, with text and element masking enabled by default. Add the tracking script before </head>, and recordings start appearing under the Replay tab. No extra configuration or separate integration required.