diff --git a/ts/session/messages/outgoing/content/data/GroupInvitationMessage.ts b/ts/session/messages/outgoing/content/data/GroupInvitationMessage.ts
index 92c2dc574..b22325fb6 100644
--- a/ts/session/messages/outgoing/content/data/GroupInvitationMessage.ts
+++ b/ts/session/messages/outgoing/content/data/GroupInvitationMessage.ts
@@ -1,13 +1,39 @@
 import { DataMessage } from './DataMessage';
 import { SignalService } from '../../../../../protobuf';
 
+interface GroupInvitationMessageParams {
+  timestamp: number;
+  identifier: string;
+  serverAddress: string;
+  channelId: number;
+  serverName: string;
+}
+
 export class GroupInvitationMessage extends DataMessage {
+  private readonly serverAddress: string;
+  private readonly channelId: number;
+  private readonly serverName: string;
+
+  constructor(params: GroupInvitationMessageParams) {
+    super({ timestamp: params.timestamp, identifier: params.identifier });
+    this.serverAddress = params.serverAddress;
+    this.channelId = params.channelId;
+    this.serverName = params.serverName;
+  }
 
   public ttl(): number {
     return this.getDefaultTTL();
   }
 
   protected dataProto(): SignalService.DataMessage {
-    throw new Error('Not implemented');
+    const groupInvitation = new SignalService.DataMessage.GroupInvitation({
+      serverAddress: this.serverAddress,
+      channelId: this.channelId,
+      serverName: this.serverName,
+    });
+
+    return new SignalService.DataMessage({
+      groupInvitation,
+    });
   }
 }
diff --git a/ts/session/messages/outgoing/content/data/RegularMessage.ts b/ts/session/messages/outgoing/content/data/RegularMessage.ts
index b3326b657..8c782cf29 100644
--- a/ts/session/messages/outgoing/content/data/RegularMessage.ts
+++ b/ts/session/messages/outgoing/content/data/RegularMessage.ts
@@ -3,6 +3,7 @@ import { SignalService } from '../../../../../protobuf';
 
 // this message type is probably to sub divise again.
 // should handle quote, body, attachmentsPointer, ... @see DataMessage in compiled.d.ts
+// Also, find a better name
 export abstract class RegularMessage extends DataMessage {
   public ttl(): number {
     return this.getDefaultTTL();
diff --git a/ts/session/messages/outgoing/index.ts b/ts/session/messages/outgoing/index.ts
index ba7a3a88d..2a8fe3bdf 100644
--- a/ts/session/messages/outgoing/index.ts
+++ b/ts/session/messages/outgoing/index.ts
@@ -42,5 +42,5 @@ export {
   ClosedGroupMessage,
   DeviceUnlinkMessage,
   GroupInvitationMessage,
-  RegularMessage
+  RegularMessage,
 };
diff --git a/ts/test/session/messages/DeviceLinkMessage_test.ts b/ts/test/session/messages/DeviceLinkMessage_test.ts
index 95577f450..f2e8e88cf 100644
--- a/ts/test/session/messages/DeviceLinkMessage_test.ts
+++ b/ts/test/session/messages/DeviceLinkMessage_test.ts
@@ -1,7 +1,7 @@
 import { expect } from 'chai';
 import { beforeEach} from 'mocha';
 
-import { DeviceLinkGrantMessage, DeviceLinkRequestMessage, ContentMessage } from '../../../session/messages/outgoing';
+import { DeviceLinkGrantMessage, DeviceLinkRequestMessage } from '../../../session/messages/outgoing';
 import { SignalService } from '../../../protobuf';
 import { LokiProfile } from '../../../types/Message';
 
diff --git a/ts/test/session/messages/GroupInvitationMessage_test.ts b/ts/test/session/messages/GroupInvitationMessage_test.ts
new file mode 100644
index 000000000..e26f24f82
--- /dev/null
+++ b/ts/test/session/messages/GroupInvitationMessage_test.ts
@@ -0,0 +1,37 @@
+import { expect } from 'chai';
+import { beforeEach} from 'mocha';
+
+import { GroupInvitationMessage } from '../../../session/messages/outgoing';
+import { SignalService } from '../../../protobuf';
+
+describe('GroupInvitationMessage', () => {
+    let message: GroupInvitationMessage;
+    const timestamp = Date.now();
+    const identifier = '123456';
+    const serverAddress = 'http://localhost';
+    const channelId = 1;
+    const serverName = 'test';
+
+    beforeEach(() => {
+        message = new GroupInvitationMessage({
+            timestamp,
+            identifier,
+            serverAddress,
+            channelId,
+            serverName,
+        });
+    });
+
+    it('dataMessage.groupInvitation has serverAddress, channelId, and serverName set', () => {
+        const plainText = message.plainTextBuffer();
+        const decoded = SignalService.Content.toObject(SignalService.Content.decode(plainText));
+
+        expect(decoded.dataMessage.groupInvitation).to.have.property('serverAddress', serverAddress);
+        expect(decoded.dataMessage.groupInvitation).to.have.property('channelId', channelId);
+        expect(decoded.dataMessage.groupInvitation).to.have.property('serverName', serverName);
+    });
+
+    it('ttl of 1 day', () => {
+        expect(message.ttl()).to.equal(24 * 60 * 60 * 1000);
+    });
+});