diff --git a/README.md b/README.md
index 4fbc6550..9cab60d4 100644
--- a/README.md
+++ b/README.md
@@ -92,8 +92,8 @@ details.
 
 `WireframeApp` defaults to a simple `Envelope` containing a message ID and raw
 payload bytes. Applications can supply their own envelope type by calling
-`WireframeApp::<_, _, MyEnv>::new_with_envelope()`. The custom type must
-implement the `Packet` trait:
+`WireframeApp::<_, _, MyEnv>::new()`. The custom type must implement the
+`Packet` trait:
 
 ```rust
 use wireframe::app::{Packet, WireframeApp};
@@ -107,7 +107,7 @@ impl Packet for MyEnv {
     fn from_parts(id: u32, data: Vec<u8>) -> Self { Self { id, data } }
 }
 
-let app = WireframeApp::<_, _, MyEnv>::new_with_envelope()
+let app = WireframeApp::<_, _, MyEnv>::new()
     .unwrap()
     .route(1, std::sync::Arc::new(|env: &MyEnv| Box::pin(async move { /* ... */ })))
     .unwrap();
diff --git a/examples/echo.rs b/examples/echo.rs
index 91840076..1791492c 100644
--- a/examples/echo.rs
+++ b/examples/echo.rs
@@ -5,7 +5,10 @@
 
 use std::io;
 
-use wireframe::{app::WireframeApp, server::WireframeServer};
+use wireframe::{
+    app::{Envelope, WireframeApp},
+    server::WireframeServer,
+};
 
 #[tokio::main]
 async fn main() -> io::Result<()> {
@@ -14,7 +17,7 @@ async fn main() -> io::Result<()> {
             .unwrap()
             .route(
                 1,
-                std::sync::Arc::new(|_| {
+                std::sync::Arc::new(|_: &Envelope| {
                     Box::pin(async move {
                         println!("echo request received");
                         // `WireframeApp` automatically echoes the envelope back.
diff --git a/examples/metadata_routing.rs b/examples/metadata_routing.rs
index 8fa7e5b1..45459ac5 100644
--- a/examples/metadata_routing.rs
+++ b/examples/metadata_routing.rs
@@ -67,7 +67,7 @@ async fn main() -> io::Result<()> {
         .serializer(HeaderSerializer)
         .route(
             1,
-            Arc::new(|_env| {
+            Arc::new(|_env: &Envelope| {
                 Box::pin(async move {
                     println!("received ping message");
                 })
@@ -76,7 +76,7 @@ async fn main() -> io::Result<()> {
         .unwrap()
         .route(
             2,
-            Arc::new(|_env| {
+            Arc::new(|_env: &Envelope| {
                 Box::pin(async move {
                     println!("received pong message");
                 })
diff --git a/examples/ping_pong.rs b/examples/ping_pong.rs
index edde533e..ed39b217 100644
--- a/examples/ping_pong.rs
+++ b/examples/ping_pong.rs
@@ -130,7 +130,7 @@ impl<E: Packet> Transform<HandlerService<E>> for Logging {
 fn build_app() -> AppResult<WireframeApp> {
     WireframeApp::new()?
         .serializer(BincodeSerializer)
-        .route(PING_ID, Arc::new(|_| Box::pin(ping_handler())))?
+        .route(PING_ID, Arc::new(|_: &Envelope| Box::pin(ping_handler())))?
         .wrap(PongMiddleware)?
         .wrap(Logging)
 }
diff --git a/src/app.rs b/src/app.rs
index 140b8a84..a84df128 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -247,27 +247,49 @@ where
     }
 }
 
-impl WireframeApp<BincodeSerializer, (), Envelope> {
+impl<E> WireframeApp<BincodeSerializer, (), E>
+where
+    E: Packet,
+{
     /// Construct a new empty application builder.
     ///
     /// # Errors
     ///
-    /// This function currently never returns an error but uses the
-    /// [`Result`] type for forward compatibility.
+    /// This function currently never returns an error but uses [`Result`] for
+    /// forward compatibility.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use wireframe::app::{Packet, WireframeApp};
+    ///
+    /// #[derive(bincode::Encode, bincode::BorrowDecode)]
+    /// struct MyEnv {
+    ///     id: u32,
+    ///     data: Vec<u8>,
+    /// }
+    ///
+    /// impl Packet for MyEnv {
+    ///     fn id(&self) -> u32 { self.id }
+    ///     fn into_parts(self) -> (u32, Vec<u8>) { (self.id, self.data) }
+    ///     fn from_parts(id: u32, data: Vec<u8>) -> Self { Self { id, data } }
+    /// }
+    ///
+    /// let app = WireframeApp::<_, _, MyEnv>::new().expect("failed to create app");
+    /// ```
     pub fn new() -> Result<Self> { Ok(Self::default()) }
-}
 
-impl<E> WireframeApp<BincodeSerializer, (), E>
-where
-    E: Packet,
-{
     /// Construct a new application builder using a custom envelope type.
     ///
+    /// Deprecated: call [`WireframeApp::new`] with explicit envelope type
+    /// parameters.
+    ///
     /// # Errors
     ///
     /// This function currently never returns an error but uses [`Result`] for
     /// forward compatibility.
-    pub fn new_with_envelope() -> Result<Self> { Ok(Self::default()) }
+    #[deprecated(note = "use `WireframeApp::<_, _, E>::new()` instead")]
+    pub fn new_with_envelope() -> Result<Self> { Self::new() }
 }
 
 impl<S, C, E> WireframeApp<S, C, E>
diff --git a/tests/lifecycle.rs b/tests/lifecycle.rs
index a81068b0..297f3e5f 100644
--- a/tests/lifecycle.rs
+++ b/tests/lifecycle.rs
@@ -49,7 +49,7 @@ where
     let setup_cb = call_counting_callback(setup, state);
     let teardown_cb = call_counting_callback(teardown, ());
 
-    WireframeApp::<_, _, E>::new_with_envelope()
+    WireframeApp::<_, _, E>::new()
         .expect("failed to create app")
         .on_connection_setup(move || setup_cb(()))
         .expect("setup callback")
@@ -74,7 +74,7 @@ async fn setup_without_teardown_runs() {
     let setup_count = Arc::new(AtomicUsize::new(0));
     let cb = call_counting_callback(&setup_count, ());
 
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("failed to create app")
         .on_connection_setup(move || cb(()))
         .expect("setup callback");
@@ -89,7 +89,7 @@ async fn teardown_without_setup_does_not_run() {
     let teardown_count = Arc::new(AtomicUsize::new(0));
     let cb = call_counting_callback(&teardown_count, ());
 
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("failed to create app")
         .on_connection_teardown(cb)
         .expect("teardown callback");
diff --git a/tests/response.rs b/tests/response.rs
index 20a5857c..60b9de04 100644
--- a/tests/response.rs
+++ b/tests/response.rs
@@ -6,7 +6,7 @@
 use bytes::BytesMut;
 use rstest::rstest;
 use wireframe::{
-    app::WireframeApp,
+    app::{Envelope, WireframeApp},
     frame::{Endianness, FrameProcessor, LengthFormat, LengthPrefixedProcessor},
     message::Message,
     serializer::BincodeSerializer,
@@ -39,7 +39,7 @@ impl<'de> bincode::BorrowDecode<'de, ()> for FailingResp {
 /// Tests that sending a response serialises and frames the data correctly,
 /// and that the response can be decoded and deserialised back to its original value asynchronously.
 async fn send_response_encodes_and_frames() {
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("failed to create app")
         .frame_processor(LengthPrefixedProcessor::default())
         .serializer(BincodeSerializer);
@@ -131,7 +131,7 @@ fn custom_length_roundtrip(
 
 #[tokio::test]
 async fn send_response_propagates_write_error() {
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("app creation failed")
         .frame_processor(LengthPrefixedProcessor::default());
 
@@ -190,7 +190,7 @@ fn encode_fails_for_length_too_large(#[case] fmt: LengthFormat, #[case] len: usi
 /// This test sends a `FailingResp` using `send_response` and asserts that the resulting
 /// error is of the `Serialize` variant, indicating a failure during response encoding.
 async fn send_response_returns_encode_error() {
-    let app = WireframeApp::new().expect("failed to create app");
+    let app = WireframeApp::<_, _, Envelope>::new().expect("failed to create app");
     let err = app
         .send_response(&mut Vec::new(), &FailingResp)
         .await
diff --git a/tests/routes.rs b/tests/routes.rs
index dbaa1652..93888cab 100644
--- a/tests/routes.rs
+++ b/tests/routes.rs
@@ -40,7 +40,7 @@ struct Echo(u8);
 async fn handler_receives_message_and_echoes_response() {
     let called = Arc::new(AtomicUsize::new(0));
     let called_clone = called.clone();
-    let app = WireframeApp::<_, _, TestEnvelope>::new_with_envelope()
+    let app = WireframeApp::<_, _, TestEnvelope>::new()
         .expect("failed to create app")
         .frame_processor(LengthPrefixedProcessor::default())
         .route(
@@ -79,7 +79,7 @@ async fn handler_receives_message_and_echoes_response() {
 
 #[tokio::test]
 async fn multiple_frames_processed_in_sequence() {
-    let app = WireframeApp::<_, _, TestEnvelope>::new_with_envelope()
+    let app = WireframeApp::<_, _, TestEnvelope>::new()
         .expect("failed to create app")
         .frame_processor(LengthPrefixedProcessor::default())
         .route(
diff --git a/tests/wireframe_protocol.rs b/tests/wireframe_protocol.rs
index 79f107dc..774cb79e 100644
--- a/tests/wireframe_protocol.rs
+++ b/tests/wireframe_protocol.rs
@@ -16,7 +16,7 @@ use tokio_util::sync::CancellationToken;
 use wireframe::{
     ConnectionContext,
     WireframeProtocol,
-    app::WireframeApp,
+    app::{Envelope, WireframeApp},
     connection::ConnectionActor,
     push::PushQueues,
 };
@@ -51,7 +51,7 @@ async fn builder_produces_protocol_hooks() {
     let protocol = TestProtocol {
         counter: counter.clone(),
     };
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("failed to create app")
         .with_protocol(protocol);
     let mut hooks = app.protocol_hooks();
@@ -75,7 +75,7 @@ async fn connection_actor_uses_protocol_from_builder() {
     let protocol = TestProtocol {
         counter: counter.clone(),
     };
-    let app = WireframeApp::new()
+    let app = WireframeApp::<_, _, Envelope>::new()
         .expect("failed to create app")
         .with_protocol(protocol);