diff --git a/src/prelude.rs b/src/prelude.rs
index 381abf9..f38e111 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -11,7 +11,7 @@ pub use std::{
     rc::Rc,
     str::FromStr,
     task::{Context, Poll},
-    time::{Duration, Instant},
+    time::Duration,
 };
 pub use tokio::{
     net::{TcpListener, TcpStream},
diff --git a/src/server.rs b/src/server.rs
index c939173..eac0dea 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -1,5 +1,7 @@
 use crate::prelude::*;
 
+type Id = u64;
+
 pub(crate) struct Args {
     pub(crate) port: u16,
 }
@@ -11,9 +13,9 @@ impl Default for Args {
 }
 
 pub(crate) struct App {
-    clients: Vec<Client>,
+    clients: BTreeMap<Id, Client>,
     listener: TcpListener,
-    next_client_id: u64,
+    next_client_id: Id,
 }
 
 impl App {
@@ -31,7 +33,9 @@ impl App {
         let previous_client_count = self.clients.len();
 
         let mut new_messages = vec![];
-        for client in &mut self.clients {
+        let mut clients_to_delete = vec![];
+        for (id, client) in &mut self.clients {
+            let id = *id;
             {
                 let mut stream = pin!(&mut client.stream);
                 match <_ as futures_sink::Sink<Bytes>>::poll_flush(stream.as_mut(), cx) {
@@ -71,9 +75,9 @@ impl App {
                 Poll::Ready(Err(err)) => {
                     tracing::error!(?err, "client.poll_next error");
                 }
-                Poll::Ready(Ok(None)) => client.closed = true,
+                Poll::Ready(Ok(None)) => clients_to_delete.push(id),
                 Poll::Ready(Ok(Some(ToServer::ChatLine { line, sequence }))) => {
-                    tracing::debug!(id = client.id, ?line);
+                    tracing::debug!(id = id, ?line);
                     if sequence != client.sequence {
                         tracing::error!(
                             expected = client.sequence,
@@ -82,24 +86,19 @@ impl App {
                         );
                         return Poll::Ready(Err(anyhow!("Sequence mismatch")));
                     }
-                    tracing::info!(?sequence, id = client.id);
+                    tracing::info!(?sequence, id = id);
                     client.sequence += 1;
-                    new_messages.push(Rc::new(ToClient::ChatLine {
-                        id: client.id,
-                        line,
-                    }));
+                    new_messages.push(Rc::new(ToClient::ChatLine { id, line }));
                 }
             }
         }
 
-        self.clients.retain(|client| {
-            if client.closed {
-                tracing::info!(id = client.id, "Closing client");
-            }
-            !client.closed
-        });
+        for id in clients_to_delete {
+            tracing::info!(?id, "Closing client");
+            self.clients.remove(&id);
+        }
 
-        for client in &mut self.clients {
+        for client in &mut self.clients.values_mut() {
             for msg in &new_messages {
                 client.outbox.push_back(Rc::clone(msg));
             }
@@ -112,7 +111,6 @@ impl App {
                 cx.waker().wake_by_ref();
                 let stream = Framed::new(stream, LengthDelimitedCodec::new());
                 let client = Client {
-                    closed: false,
                     id: self.next_client_id,
                     outbox: Default::default(),
                     sequence: 0,
@@ -120,7 +118,7 @@ impl App {
                 };
                 self.next_client_id += 1;
                 tracing::info!(id = client.id, "Accepted client");
-                self.clients.push(client);
+                self.clients.insert(client.id, client);
             }
         }
 
@@ -133,7 +131,6 @@ impl App {
 }
 
 struct Client {
-    closed: bool,
     id: u64,
     outbox: VecDeque<Rc<ToClient>>,
     sequence: u64,