diff --git a/index.js b/index.js
index b80692d..7025444 100644
--- a/index.js
+++ b/index.js
@@ -45,6 +45,9 @@ async function onTrack(event, settings) {
     const endpoint = new URL(`${baseUrl}/capture/`)
     endpoint.searchParams.set('ts', event.timestamp)
 
+    const namespace = uuidv5.uuidv5('null', 'PostHog', true)
+    const uuid = uuidv5.uuidv5(namespace, event.messageId)
+
     if (event.properties && event.properties.url) {
         event.properties['$current_url'] = event.properties.url
         delete event.properties.url
@@ -67,6 +70,7 @@ async function onTrack(event, settings) {
 
     const res = await fetch(endpoint, {
         body: JSON.stringify({
+            uuid,
             timestamp: event.timestamp,
             event: event.event,
             api_key: settings.apiKey,
diff --git a/package.json b/package.json
index aa82c3b..36c4dfe 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
   "license": "MIT",
   "devDependencies": {
     "jest": "^29.5.0",
-    "lodash": "^4.17.21"
+    "lodash": "^4.17.21",
+    "uuidv5": "^1.0.0"
   }
-}
+}
\ No newline at end of file
diff --git a/prepare-tests.sh b/prepare-tests.sh
index 045cfa6..e5e1870 100755
--- a/prepare-tests.sh
+++ b/prepare-tests.sh
@@ -7,6 +7,12 @@ set -e
 cp index.js module.js
 
 cat >> module.js <<EOF
+// Segment exposes uuidv5 as an object, so it is callable at uuidv5.uuidv5, see:
+// https://segment.com/docs/connections/functions/destination-functions/#runtime-and-dependencies
+const __uuidv5 = require('uuidv5')
+const uuidv5 = {
+    uuidv5: __uuidv5
+}
 module.exports = {
     onTrack,
     onIdentify,
diff --git a/test.js b/test.js
index 1df02eb..90ff4b9 100644
--- a/test.js
+++ b/test.js
@@ -69,6 +69,7 @@ describe('Segment Integration', () => {
                     segment_groupId: 'GroupId1',
                 },
                 timestamp: '2015-12-12T19:11:01.249Z',
+                uuid: '2e1e762e-c318-5c5b-a96e-955e840a3cf2',
             })
         })
     })
@@ -86,6 +87,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$identify',
                 api_key: 'test-key',
                 properties: {
@@ -123,6 +125,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$set',
                 api_key: 'test-key',
                 properties: {
@@ -163,6 +166,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$groupidentify',
                 api_key: 'test-key',
                 properties: {
@@ -199,6 +203,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$pageview',
                 api_key: 'test-key',
                 properties: {
@@ -228,6 +233,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$screen',
                 api_key: 'test-key',
                 properties: {
@@ -255,6 +261,7 @@ describe('Segment Integration', () => {
 
             expect(JSON.parse(lastFetchCall[1].body)).toEqual({
                 timestamp: '2015-02-23T22:28:55.111Z',
+                uuid: '38c091ab-1857-58c9-bf58-b98a022f95dd',
                 event: '$create_alias',
                 api_key: 'test-key',
                 properties: {