diff --git a/server.js b/server.js
index b8fadc4..4ef2b0c 100644
--- a/server.js
+++ b/server.js
@@ -4783,8 +4783,8 @@ app.post('/api/contact', contactRateLimit, async (req, res) => {
       res.status(400).json({ message: 'First name is required.' })
       return
     }
-    if (!lastName || typeof lastName !== 'string' || lastName.trim().length < 1 || lastName.trim().length > 100) {
-      res.status(400).json({ message: 'Last name is required.' })
+    if (lastName !== undefined && lastName !== null && (typeof lastName !== 'string' || lastName.trim().length > 100)) {
+      res.status(400).json({ message: 'Last name is too long.' })
       return
     }
     if (!email || typeof email !== 'string' || !/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email.trim())) {
@@ -4802,7 +4802,7 @@ app.post('/api/contact', contactRateLimit, async (req, res) => {
       return
     }
 
-    const trimmedName = `${firstName.trim()} ${lastName.trim()}`.trim()
+    const trimmedName = [firstName.trim(), typeof lastName === 'string' ? lastName.trim() : ''].filter(Boolean).join(' ')
     const trimmedEmail = email.trim()
     const trimmedMessage = message.trim()
     const normalizedMessageType = normalizeMessageType(messageType)