diff --git a/js/invitees.js b/js/invitees.js
index 802268c..b986f14 100644
--- a/js/invitees.js
+++ b/js/invitees.js
@@ -13,7 +13,9 @@
   'use strict';
 
   var DEBOUNCE_MS = 250;
-  var SEPARATOR = /[;,]/;
+  /* Must match the server's attendee parsing: whitespace, comma and
+   * semicolon all separate entries. */
+  var SEPARATOR = /[\s;,]+/;
 
   var input = document.getElementById('atocal-attendees');
 
@@ -59,7 +61,7 @@
   }
 
   function commit(email) {
-    var parts = input.value.split(/([;,])/);
+    var parts = input.value.split(/([\s;,]+)/);
     parts.pop();
     var prefix = parts.join('').replace(/\s+$/, '');
 
diff --git a/tests/js/invitees.test.mjs b/tests/js/invitees.test.mjs
index b6734f3..bc5ea3b 100644
--- a/tests/js/invitees.test.mjs
+++ b/tests/js/invitees.test.mjs
@@ -125,4 +125,29 @@ describe('invitee suggestions', () => {
     expect(list.hidden).toBe(true);
     expect(list.children).toHaveLength(0);
   });
+
+  it('searches only the last whitespace-separated fragment', async () => {
+    fetch.mockReturnValue(response([BOB]));
+
+    type('alice@example.com bo');
+    await settle();
+
+    expect(fetch).toHaveBeenCalledWith(
+      SEARCH_URL + '?query=bo',
+      expect.objectContaining({ headers: { Accept: 'application/json' } })
+    );
+  });
+
+  it('keeps whitespace-separated entries when picking a contact', async () => {
+    fetch.mockReturnValue(response([BOB]));
+
+    type('alice@example.com bo');
+    await settle();
+
+    list.querySelector('button').dispatchEvent(
+      new MouseEvent('mousedown', { bubbles: true, cancelable: true })
+    );
+
+    expect(input.value).toBe('alice@example.com bob@example.com, ');
+  });
 });