diff --git a/src/app/api/auth/signin/route.ts b/src/app/api/auth/signin/route.ts
index 68ead11..c9dd61d 100644
--- a/src/app/api/auth/signin/route.ts
+++ b/src/app/api/auth/signin/route.ts
@@ -11,8 +11,8 @@ export async function POST(request: Request) {
   }
 
   try {
-    // Find user - use parameterized query
-    const users = await sql`
+    // Find or create user
+    let users = await sql`
       SELECT u.id, u.email, fm.family_id as family_id
       FROM users u
       LEFT JOIN family_members fm ON fm.user_id = u.id
@@ -20,10 +20,27 @@ export async function POST(request: Request) {
       LIMIT 1
     `;
 
-    const user = users?.[0];
+    let user = users?.[0];
+
+    // Create user if not found
+    if (!user) {
+      const newUserId = crypto.randomUUID();
+      await sql`
+        INSERT INTO users (id, email, created_at, updated_at)
+        VALUES (${newUserId}, ${email}, NOW(), NOW())
+      `;
+
+      // Fetch the newly created user
+      users = await sql`
+        SELECT u.id, u.email
+        FROM users u
+        WHERE u.id = ${newUserId}
+      `;
+      user = users?.[0];
+    }
 
     if (!user) {
-      return NextResponse.json({ error: "User not found" }, { status: 404 });
+      return NextResponse.json({ error: "Failed to create user" }, { status: 500 });
     }
 
     // Create session token