diff --git a/back/api/auth.js b/back/api/auth.js
index c1a2640..ccec218 100644
--- a/back/api/auth.js
+++ b/back/api/auth.js
@@ -24,6 +24,13 @@ router.post('/login', async (req, res) => {
 router.post('/register', async (req, res) => {
     const { username, password } = req.body;
     const connection = await getConnection();
+
+    const use = await getUserByUsername(connection, username);
+    if (use[0]) {
+        connection.end();
+        return res.status(401).send({ error: 'Username already exists' });
+    }
+
     const hash = sha256(password);
     await addUser(connection, username, hash);
     connection.end();
diff --git a/back/api/channels.js b/back/api/channels.js
index 01f24d0..817af9f 100644
--- a/back/api/channels.js
+++ b/back/api/channels.js
@@ -70,6 +70,17 @@ router.post('/add', async (req, res) => {
         return res.status(401).send({ error: 'Invalid token' });
     }
 
+    const channel = await getChannel(connection, name);
+    if (channel[0]) {
+        connection.end();
+        return res.status(400).send({ error: 'Channel already exists' });
+    }
+
+    if (!/^[a-zA-Z0-9-_]+$/.test(name)) {
+        connection.end();
+        return res.status(400).send({ error: 'Invalid channel name' });
+    }
+
     await addChannel(connection, name, description);
     connection.end();
     res.send({ message: 'Channel added' });
diff --git a/front/src/pages/Home.tsx b/front/src/pages/Home.tsx
index c807d7a..d5d59bf 100644
--- a/front/src/pages/Home.tsx
+++ b/front/src/pages/Home.tsx
@@ -36,6 +36,7 @@ export default function Home() {
                         localStorage.removeItem("token")
                         window.location.reload()
                     }}>Logout</button>
+                    <Link to="/create-channel">Create Channel</Link>
                 </div>
             ) : (
                 <div>
@@ -43,7 +44,6 @@ export default function Home() {
                     <Link to="/register">Register</Link>
                 </div>
             )}
-            <Link to="/create-channel">Create Channel</Link>
             <h2>Channels</h2>
             <ul>
                 {channels?.map((channel) => (