diff --git a/docs/session-replay.mdx b/docs/session-replay.mdx
index 277c8dfd..dbf96552 100644
--- a/docs/session-replay.mdx
+++ b/docs/session-replay.mdx
@@ -278,6 +278,21 @@ Mixpanel reserves the right to stop ingesting replays once a customer collects r
 
 Replays are available for viewing in Mixpanel ~1 minute after the recording is captured.
 
+#### What defines a single replay?
+
+A replay is a continuous recording of a single user's activity. 
+
+On the web, a replay ends after 30 minutes of inactivity (a new replay begins automatically when the user is active again) or once it reaches a maximum length of 24 hours, whichever comes first. Both thresholds are configurable via the `record_idle_timeout_ms` (default 30 minutes) and `record_max_ms` (default 24 hours) [JavaScript init options](/docs/tracking-methods/sdks/javascript/javascript-replay#init-options). On the web, a replay is scoped to a single browser tab or window. Recording continues across page loads and navigations within that same tab (SDK v2.61.0+), but each additional tab or window is recorded as its own replay, as is activity in a different browser or on a different device. A single user's activity across multiple tabs, browsers, or devices is therefore captured as multiple replays, not one.
+ 
+On our mobile SDKs (iOS, Android, and React Native), you control capture with a sampling rate and by starting or stopping recording manually, just as you can on the web. A replay ends when the user leaves the app. 
+
+{/* ============================================================ */}
+{/* ⚠️ DO NOT REMOVE OR MODIFY the replay definition below.       */}
+{/* We are contractually/legally required to maintain it.        */}
+{/* Before any change, confirm with the PM for Session Replay    */}
+{/* AND Legal (contract implication review). — DJ, 2026-07-09    */}
+{/* ============================================================ */}
+
 #### How long are replays stored?
 
 By default, replays are stored for 30 days after the time of ingestion. Once a replay is expired, there is no way to view that replay. Enterprise plan customers with the paid session replay add-on can customize this retention period between 7 days and 360 days. For more information, reach out to your Account Manager or our sales team.