diff --git a/src/routes.rs b/src/routes.rs
index 4d4af1e..253874a 100644
--- a/src/routes.rs
+++ b/src/routes.rs
@@ -2,7 +2,13 @@
 
 use async_std::channel::Sender;
 use log::{info, warn};
-use rocket::{form::Form, get, post, response::Redirect, uri, FromForm, State};
+use rocket::{
+    form::Form,
+    get, post,
+    request::FlashMessage,
+    response::{Flash, Redirect},
+    uri, FromForm, State,
+};
 use rocket_dyn_templates::{context, Template};
 
 use crate::{
@@ -18,7 +24,7 @@ pub struct PeerForm {
 }
 
 #[get("/")]
-pub async fn home(db: &State<Database>) -> Template {
+pub async fn home(db: &State<Database>, flash: Option<FlashMessage<'_>>) -> Template {
     let peers = db.get_peers();
     let mut peers_unread = Vec::new();
     for peer in peers {
@@ -26,7 +32,7 @@ pub async fn home(db: &State<Database>) -> Template {
         peers_unread.push((peer, unread_count.to_string()));
     }
 
-    Template::render("base", context! { peers: &peers_unread })
+    Template::render("base", context! { peers: &peers_unread, flash: flash })
 }
 
 #[get("/posts/<public_key>/<msg_id>/delete")]
@@ -153,11 +159,13 @@ pub async fn subscribe_form(
     db: &State<Database>,
     tx: &State<Sender<Task>>,
     peer: Form<PeerForm>,
-) -> Redirect {
+) -> Result<Redirect, Flash<Redirect>> {
     info!("Subscribing to peer {}", &peer.public_key);
 
     if let Err(e) = utils::validate_public_key(&peer.public_key) {
-        warn!("Public key {} is invalid: {}", &peer.public_key, e)
+        let err_msg = format!("Public key {} is invalid: {}", &peer.public_key, e);
+        warn!("{}", err_msg);
+        return Err(Flash::error(Redirect::to(uri!(home)), err_msg));
     } else {
         info!("Public key {} is valid", &peer.public_key);
 
@@ -191,15 +199,20 @@ pub async fn subscribe_form(
         }
     }
 
-    Redirect::to(uri!(home))
+    Ok(Redirect::to(uri!(home)))
 }
 
 #[post("/unsubscribe", data = "<peer>")]
-pub async fn unsubscribe_form(db: &State<Database>, peer: Form<PeerForm>) -> Redirect {
+pub async fn unsubscribe_form(
+    db: &State<Database>,
+    peer: Form<PeerForm>,
+) -> Result<Redirect, Flash<Redirect>> {
     info!("Unsubscribing from peer {}", &peer.public_key);
 
     if let Err(e) = utils::validate_public_key(&peer.public_key) {
-        warn!("Public key {} is invalid: {}", &peer.public_key, e)
+        let err_msg = format!("Public key {} is invalid: {}", &peer.public_key, e);
+        warn!("{}", err_msg);
+        return Err(Flash::error(Redirect::to(uri!(home)), err_msg));
     } else {
         info!("Public key {} is valid", &peer.public_key);
         if db.remove_peer(&peer.public_key).is_ok() {
@@ -216,5 +229,5 @@ pub async fn unsubscribe_form(db: &State<Database>, peer: Form<PeerForm>) -> Red
         }
     }
 
-    Redirect::to(uri!(home))
+    Ok(Redirect::to(uri!(home)))
 }
diff --git a/static/css/lykin.css b/static/css/lykin.css
index f8bd100..0ea6505 100644
--- a/static/css/lykin.css
+++ b/static/css/lykin.css
@@ -19,6 +19,14 @@
   pointer-events: none;
 }
 
+.flash-message {
+	margin-left: auto;
+	margin-right: 0;
+	margin-top: 0;
+	margin-bottom: 0;
+	color: red;
+}
+
 .flex-container {
 	display: flex;
 	align-items: center;
diff --git a/templates/topbar.html.tera b/templates/topbar.html.tera
index fa55e68..0121b53 100644
--- a/templates/topbar.html.tera
+++ b/templates/topbar.html.tera
@@ -46,5 +46,8 @@
         <input type="submit" value="Subscribe">
         <input type="submit" value="Unsubscribe" formaction="/unsubscribe">
       </form>
+      {% if flash and flash.kind == "error" %}
+      <p class="flash-message">[ {{ flash.message }} ]</p>
+      {% endif %}
     </div>
   </div>