diff --git a/README.md b/README.md
index c3cc05e..120a858 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,7 @@ pub fn main() {
         stratus.Binary(_msg) -> stratus.continue(state)
         stratus.User(Close) -> {
           let assert Ok(_) =
-            stratus.close_with_reason(conn, stratus.GoingAway(<<"goodbye">>))
+            stratus.close(conn, stratus.GoingAway(<<"goodbye!">>))
           stratus.stop()
         }
       }
diff --git a/src/stratus.gleam b/src/stratus.gleam
index ae14b60..63f1e84 100644
--- a/src/stratus.gleam
+++ b/src/stratus.gleam
@@ -1,5 +1,6 @@
 import exception
 import gleam/bit_array
+import gleam/bool
 import gleam/bytes_tree.{type BytesTree}
 import gleam/crypto
 import gleam/erlang/charlist
@@ -72,6 +73,11 @@ pub type SocketReason {
   Exbadseq
 }
 
+pub type CustomCloseError {
+  SocketFail(SocketReason)
+  InvalidCode
+}
+
 fn convert_socket_reason(reason: socket.SocketReason) -> SocketReason {
   case reason {
     socket.Badarg -> Badarg
@@ -267,7 +273,7 @@ pub type InitializationError {
   HandshakeFailed(HandshakeError)
   // The actor failed to start, most likely due to a timeout in your `init`
   ActorFailed(actor.StartError)
-  // 
+  //
   FailedToTransferSocket(SocketReason)
 }
 
@@ -669,25 +675,38 @@ pub fn send_ping(conn: Connection, data: BitArray) -> Result(Nil, SocketReason)
   |> result.map_error(convert_socket_reason)
 }
 
-/// This will close the WebSocket connection.
-pub fn close(conn: Connection) -> Result(Nil, SocketReason) {
-  close_with_reason(conn, Normal(body: <<>>))
-}
-
 pub type CloseReason {
+  NotProvided
+  /// Status code: 1000
   Normal(body: BitArray)
+  /// Status code: 1001
   GoingAway(body: BitArray)
+  /// Status code: 1002
   ProtocolError(body: BitArray)
+  /// Status code: 1003
   UnexpectedDataType(body: BitArray)
+  /// Status code: 1007
   InconsistentDataType(body: BitArray)
+  /// Status code: 1008
   PolicyViolation(body: BitArray)
+  /// Status code: 1009
   MessageTooBig(body: BitArray)
+  /// Status code: 1010
   MissingExtensions(body: BitArray)
+  /// Status code: 1011
   UnexpectedCondition(body: BitArray)
+  /// Use [`close_custom`](#close_custom) to send a custom close code.
+  Custom(CustomCloseReason)
+}
+
+/// Use [`close_custom`](#close_custom) to send a custom close code.
+pub opaque type CustomCloseReason {
+  CustomCloseReason(code: Int, body: BitArray)
 }
 
 fn convert_close_reason(reason: CloseReason) -> websocket.CloseReason {
   case reason {
+    NotProvided -> websocket.NotProvided
     GoingAway(body:) -> websocket.GoingAway(body:)
     InconsistentDataType(body:) -> websocket.InconsistentDataType(body:)
     MessageTooBig(body:) -> websocket.MessageTooBig(body:)
@@ -697,13 +716,29 @@ fn convert_close_reason(reason: CloseReason) -> websocket.CloseReason {
     ProtocolError(body:) -> websocket.ProtocolError(body:)
     UnexpectedCondition(body:) -> websocket.UnexpectedCondition(body:)
     UnexpectedDataType(body:) -> websocket.UnexpectedDataType(body:)
+    Custom(CustomCloseReason(code:, body:)) ->
+      websocket.CustomCloseReason(code:, body:)
   }
 }
 
-/// This closes the WebSocket connection with a particular close reason.
-pub fn close_with_reason(
+/// Closes the connection with a custom close code between 1000 and 4999. 
+pub fn close_custom(
+  conn: Connection,
+  code code: Int,
+  body body: BitArray,
+) -> Result(Nil, CustomCloseError) {
+  use <- bool.guard(
+    when: code >= 5000 || code < 1000,
+    return: Error(InvalidCode),
+  )
+
+  close(conn, Custom(CustomCloseReason(code:, body:)))
+  |> result.map_error(SocketFail)
+}
+
+pub fn close(
   conn: Connection,
-  reason: CloseReason,
+  because reason: CloseReason,
 ) -> Result(Nil, SocketReason) {
   let reason = convert_close_reason(reason)
   let mask = crypto.strong_random_bytes(4)