diff --git a/react-packager/src/Activity/Types.js b/react-packager/src/Activity/Types.js
index cc996c74..80aea02b 100644
--- a/react-packager/src/Activity/Types.js
+++ b/react-packager/src/Activity/Types.js
@@ -32,5 +32,6 @@ export type Event = {
   id: number,
   name: string,
   options: Options,
+  session: string,
   startTimeStamp: [number, number],
 };
diff --git a/react-packager/src/Activity/index.js b/react-packager/src/Activity/index.js
index 4ad5ad05..7eac9f84 100644
--- a/react-packager/src/Activity/index.js
+++ b/react-packager/src/Activity/index.js
@@ -17,10 +17,12 @@ const chalk = require('chalk');
 const events = require('events');
 const formatData = require('./formatData');
 const normaliseEventData = require('./normaliseEventData');
+const os = require('os');
 
 let ENABLED = true;
 let UUID = 1;
 
+const session = `${os.hostname()}-${Date.now()}`;
 const EVENT_INDEX: {[key: number]: Event} = Object.create(null);
 const EVENT_EMITTER = new events.EventEmitter();
 
@@ -35,6 +37,7 @@ function startEvent(name: string, data: EventData = {}, options: Options = {}):
     id,
     options,
     name,
+    session,
     startTimeStamp: process.hrtime(),
   };
   logEvent(id, 'startEvent');