Session replay is a technique that records a visitor's on-page behavior — including mouse movement, clicks, scrolling, and page navigation — and reconstructs it as a video-like playback, allowing someone to watch a specific visit unfold as it happened.
Most session replay tools work by capturing DOM changes and input events rather than recording actual video, reconstructing the page and cursor movement from that data on playback, which keeps file sizes far smaller than true screen recording. It's particularly useful for diagnosing specific problems, but because it can capture form inputs and personal details, responsible implementations mask sensitive fields like passwords and payment information by default.
A team investigating a drop in signup completions might watch a session replay of a visitor repeatedly clicking a 'Submit' button that doesn't respond, revealing a JavaScript error that a funnel report alone would only show as an unexplained abandonment.
No — most session replay tools reconstruct behavior from recorded DOM changes, clicks, and cursor coordinates rather than capturing true screen video, which is why replays can look slightly different from a real recording.
It can be, since it may capture form input or on-page text — responsible tools mask sensitive fields like passwords and payment details by default, and site owners should configure exclusions for any other sensitive content.
A heatmap aggregates behavior across many visitors into one composite view; session replay shows one individual visitor's full sequence of actions in order, better for diagnosing a specific problem than spotting patterns.