What is session?

How is a session defined?

New session if: time since visitor's last hit ≥ timeout (commonly 30 min)

Every hit from a visitor is compared with their previous one. If it arrives within the timeout, it joins the current session; otherwise a new session starts. The session's traffic source (referrer, UTM parameters) is taken from its first hit.

Tools differ at the edges. Google Analytics 4 also starts a new session when a visitor returns after the timeout and, unlike Universal Analytics, no longer splits sessions at midnight or when the campaign changes mid-visit. Other tools may.

Session example

A visitor reads two blog posts at 9:00 and 9:10, leaves, then comes back from a newsletter link at 9:55. With a 30-minute timeout that's two sessions: the first sourced to Google, the second to the newsletter. If they'd returned at 9:35 instead, it would be one session of three pageviews, still credited to Google.

Why sessions matter

Sessions measure visits rather than people, which is the right unit for engagement questions (did this visit go anywhere?) and for channel reporting (which source started this visit?). A visitor who comes back five times is five sessions — useful when you want to know how often people return.

Common session pitfalls

• Comparing sessions across tools. Different timeout and split rules make session counts disagree by 10–20% even on identical traffic.
• Long reads timing out. Someone reading a 40-minute guide without scrolling may be split into two sessions if the tool records no activity in between.
• Self-referrals. A payment provider or auth domain that redirects back to your site can start a new session credited to that domain unless it's excluded.
• Sessions vs visitors in conversion rates. Session-based conversion rates are lower than visitor-based ones for the same traffic; state which one you report.

How VisitTrack defines a session

VisitTrack uses a 30-minute inactivity timeout: any pageview or event within 30 minutes of the visitor's last one extends the current session, and the session keeps the referrer, UTM source, medium and campaign of the hit that started it. Engagement pings sent when the visitor leaves or switches tabs count as activity, so the session's duration reflects real time on site. Events sent from your server join the same session model, so funnels and session counts work the same for them.