--- title: Session length description: This article explains visit session length in AudienceStream. url: https://docs.tealium.com/server-side/attributes/session-length/ --- ## How it works Session length determines when AudienceStream ends a visit. When a visit reaches the session length without a new event, the visit ends and AudienceStream performs end-of-visit processing. The next event from the visitor starts a new visit. AudienceStream has a maximum visit length of 24 hours, regardless of event activity. ## Session lengths In AudienceStream, the default session length is set based on the platform that sends the events: * **Web**: 30 minutes for multiple events, 10 minutes for a single event without a follow-up event. * **Mobile App**: 2 minutes. * **Omnichannel**: 1 minute. * **File Import**: 1 minute. * **Collect API**: 30 minutes. * **All Others**: 30 minutes. The platform is based on the reserved attribute named `platform` according to the following values: * **Mobile**: `platform` is set to one of the following: `android`,`ios`,`win`,`bb10`, or `native_mobile`. * **Web**: `platform` is set to `web` or not set. ## Customize session length To customize the session length, set the data layer variable `_dc_ttl_` to a value in milliseconds on the first event of a session. The minimum value of `_dc_ttl_` is `5000` (5 seconds) and the maximum value of is `1800000` (30 minutes). For example, to set the session length to five minutes, add the following to the event: `"_dc_ttl_": 300000`. The session length cannot be changed after it has been set.
To set a custom session length, do not set the `platform` variable. If you set a custom value for `platform`, the session length defaults to 30 minutes.