Session health
See whether a client's site code keeps starting new sessions, what is causing it, and which sessions to open to check.
Overview
Mythic starts a new session only after 4 hours of inactivity. When a device starts a new session within 5 minutes of its previous one, or while the previous one is still going, the site's own code caused it. The Session health screen shows how often that happens for one client.
Restarted sessions split one visit into many short ones, which inflates session counts, shortens durations and breaks replays and attribution.
Open Session health from a client's Monitor menu. It is agency only.
Read the screen
Pick a window of 1, 3, 7 or 30 days. The banner gives the status:
| Status | Meaning |
|---|---|
| Restarting sessions | 5% or more of the window's sessions are restarts |
| Healthy | Below 5% |
| Too few sessions to judge | Fewer than 100 sessions in the window |
| No sessions | No web sessions in the window |
The tiles show the window's sessions, how many were restarts, and how many devices had at least one.
How restarted sessions began counts the first event of each restarted
session. When most of them begin with $identify, the site calls reset() on
page load before identify(), often while its login state is still loading.
Call reset() only when a user logs out.
Recent restarts lists the latest ones. Open Previous and New to see both sessions on the Sessions screen.
Common causes
reset()runs on every page load, for example in code that treats "login still loading" as "logged out".- The SDK is installed twice on the page.
- Code clears local storage or cookies on page load.
A visitor moving between subdomains, or logging out and back in, also counts, which is why a small share is normal.
Alerts
Mythic checks every client daily at about 08:30 UTC over the last 3 days and opens a Session health alert when a client is restarting sessions. The alert resolves once the client is back under 5%. Route it to Slack or a webhook on the Alerts screen.