diff --git a/examples/Cargo.toml b/examples/Cargo.toml
index 5c3e7e8b5..6d9064212 100644
--- a/examples/Cargo.toml
+++ b/examples/Cargo.toml
@@ -290,13 +290,13 @@ hyper-warp-multiplex = ["hyper-warp"]
 uds = ["tokio-stream/net", "dep:tower", "dep:hyper"]
 streaming = ["tokio-stream", "dep:h2"]
 mock = ["tokio-stream", "dep:tower"]
-tower = ["dep:hyper", "dep:tower", "dep:http"]
+tower = ["dep:hyper", "tower/timeout", "dep:http"]
 json-codec = ["dep:serde", "dep:serde_json", "dep:bytes"]
 compression = ["tonic/gzip"]
 tls = ["tonic/tls"]
 tls-rustls = ["dep:hyper", "dep:hyper-rustls", "dep:tower", "tower-http/util", "tower-http/add-extension", "dep:rustls-pemfile", "dep:tokio-rustls"]
 dynamic-load-balance = ["dep:tower"]
-timeout = ["tokio/time", "dep:tower"]
+timeout = ["tokio/time", "tower/timeout"]
 tls-client-auth = ["tonic/tls"]
 types = ["dep:tonic-types"]
 h2c = ["dep:hyper", "dep:tower", "dep:http"]
diff --git a/tonic/Cargo.toml b/tonic/Cargo.toml
index 013cc6e72..303cf2619 100644
--- a/tonic/Cargo.toml
+++ b/tonic/Cargo.toml
@@ -26,24 +26,26 @@ version = "0.10.2"
 codegen = ["dep:async-trait"]
 gzip = ["dep:flate2"]
 zstd = ["dep:zstd"]
-default = ["transport", "codegen", "prost"]
+default = ["channel", "codegen", "prost"]
 prost = ["dep:prost"]
 tls = ["dep:rustls-pemfile", "transport", "dep:tokio-rustls", "dep:rustls", "tokio/rt", "tokio/macros"]
 tls-roots = ["tls-roots-common", "dep:rustls-native-certs"]
-tls-roots-common = ["tls"]
+tls-roots-common = ["tls", "channel"]
 tls-webpki-roots = ["tls-roots-common", "dep:webpki-roots"]
 transport = [
   "dep:async-stream",
   "dep:axum",
-  "channel",
   "dep:h2",
-  "dep:hyper",
-  "tokio/net",
-  "tokio/time",
-  "dep:tower",
+  "dep:hyper", "hyper?/server",
+  "tokio/net", "tokio/time",
+  "dep:tower", "tower?/util", "tower?/limit",
+]
+channel = [
+  "transport",
+  "dep:hyper", "hyper?/client",
+  "dep:tower", "tower?/balance", "tower?/buffer", "tower?/discover", "tower?/load", "tower?/make",
   "dep:hyper-timeout",
 ]
-channel = []
 
 # [[bench]]
 # name = "bench_main"
@@ -70,12 +72,14 @@ async-trait = {version = "0.1.13", optional = true}
 
 # transport
 h2 = {version = "0.3.17", optional = true}
-hyper = {version = "0.14.26", features = ["full"], optional = true}
-hyper-timeout = {version = "0.4", optional = true}
+hyper = {version = "0.14.26", features = ["http1", "http2", "runtime", "stream"], optional = true}
 tokio-stream = "0.1"
-tower = {version = "0.4.7", default-features = false, features = ["balance", "buffer", "discover", "limit", "load", "make", "timeout", "util"], optional = true}
+tower = {version = "0.4.7", default-features = false, optional = true}
 axum = {version = "0.6.9", default_features = false, optional = true}
 
+# channel
+hyper-timeout = {version = "0.4", optional = true}
+
 # rustls
 async-stream = { version = "0.3", optional = true }
 rustls-pemfile = { version = "1.0", optional = true }
diff --git a/tonic/src/transport/error.rs b/tonic/src/transport/error.rs
index d2a1c7bb2..92a910498 100644
--- a/tonic/src/transport/error.rs
+++ b/tonic/src/transport/error.rs
@@ -15,7 +15,9 @@ struct ErrorImpl {
 #[derive(Debug)]
 pub(crate) enum Kind {
     Transport,
+    #[cfg(feature = "channel")]
     InvalidUri,
+    #[cfg(feature = "channel")]
     InvalidUserAgent,
 }
 
@@ -35,10 +37,12 @@ impl Error {
         Error::new(Kind::Transport).with(source)
     }
 
+    #[cfg(feature = "channel")]
     pub(crate) fn new_invalid_uri() -> Self {
         Error::new(Kind::InvalidUri)
     }
 
+    #[cfg(feature = "channel")]
     pub(crate) fn new_invalid_user_agent() -> Self {
         Error::new(Kind::InvalidUserAgent)
     }
@@ -46,7 +50,9 @@ impl Error {
     fn description(&self) -> &str {
         match &self.inner.kind {
             Kind::Transport => "transport error",
+            #[cfg(feature = "channel")]
             Kind::InvalidUri => "invalid URI",
+            #[cfg(feature = "channel")]
             Kind::InvalidUserAgent => "user agent is not a valid header value",
         }
     }
diff --git a/tonic/src/transport/mod.rs b/tonic/src/transport/mod.rs
index a0435c797..9fdaab6ad 100644
--- a/tonic/src/transport/mod.rs
+++ b/tonic/src/transport/mod.rs
@@ -87,6 +87,7 @@
 //!
 //! [rustls]: https://docs.rs/rustls/0.16.0/rustls/
 
+#[cfg(feature = "channel")]
 pub mod channel;
 pub mod server;
 
@@ -110,10 +111,11 @@ pub use self::tls::Certificate;
 pub use axum::{body::BoxBody as AxumBoxBody, Router as AxumRouter};
 pub use hyper::{Body, Uri};
 
+#[cfg(feature = "channel")]
 pub(crate) use self::service::executor::Executor;
 
-#[cfg(feature = "tls")]
-#[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
+#[cfg(all(feature = "channel", feature = "tls"))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "channel", feature = "tls"))))]
 pub use self::channel::ClientTlsConfig;
 #[cfg(feature = "tls")]
 #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
@@ -122,4 +124,5 @@ pub use self::server::ServerTlsConfig;
 #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
 pub use self::tls::Identity;
 
+#[cfg(feature = "channel")]
 type BoxFuture<'a, T> = std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send + 'a>>;
diff --git a/tonic/src/transport/service/io.rs b/tonic/src/transport/service/io.rs
index 2230b9b2e..865ea814f 100644
--- a/tonic/src/transport/service/io.rs
+++ b/tonic/src/transport/service/io.rs
@@ -1,4 +1,5 @@
 use crate::transport::server::Connected;
+#[cfg(feature = "channel")]
 use hyper::client::connect::{Connected as HyperConnected, Connection};
 use std::io;
 use std::io::IoSlice;
@@ -15,20 +16,24 @@ pub(in crate::transport) trait Io:
 
 impl<T> Io for T where T: AsyncRead + AsyncWrite + Send + 'static {}
 
+#[cfg(feature = "channel")]
 pub(crate) struct BoxedIo(Pin<Box<dyn Io>>);
 
+#[cfg(feature = "channel")]
 impl BoxedIo {
     pub(in crate::transport) fn new<I: Io>(io: I) -> Self {
         BoxedIo(Box::pin(io))
     }
 }
 
+#[cfg(feature = "channel")]
 impl Connection for BoxedIo {
     fn connected(&self) -> HyperConnected {
         HyperConnected::new()
     }
 }
 
+#[cfg(feature = "channel")]
 impl Connected for BoxedIo {
     type ConnectInfo = NoneConnectInfo;
 
@@ -37,9 +42,11 @@ impl Connected for BoxedIo {
     }
 }
 
+#[cfg(feature = "channel")]
 #[derive(Copy, Clone)]
 pub(crate) struct NoneConnectInfo;
 
+#[cfg(feature = "channel")]
 impl AsyncRead for BoxedIo {
     fn poll_read(
         mut self: Pin<&mut Self>,
@@ -50,6 +57,7 @@ impl AsyncRead for BoxedIo {
     }
 }
 
+#[cfg(feature = "channel")]
 impl AsyncWrite for BoxedIo {
     fn poll_write(
         mut self: Pin<&mut Self>,
diff --git a/tonic/src/transport/service/mod.rs b/tonic/src/transport/service/mod.rs
index 69d850f10..3a51d6a90 100644
--- a/tonic/src/transport/service/mod.rs
+++ b/tonic/src/transport/service/mod.rs
@@ -1,26 +1,34 @@
+#[cfg(feature = "channel")]
 mod add_origin;
+#[cfg(feature = "channel")]
 mod connection;
+#[cfg(feature = "channel")]
 mod connector;
+#[cfg(feature = "channel")]
 mod discover;
+#[cfg(feature = "channel")]
 pub(crate) mod executor;
 pub(crate) mod grpc_timeout;
 mod io;
+#[cfg(feature = "channel")]
 mod reconnect;
 mod router;
 #[cfg(feature = "tls")]
 mod tls;
+#[cfg(feature = "channel")]
 mod user_agent;
 
-pub(crate) use self::add_origin::AddOrigin;
-pub(crate) use self::connection::Connection;
-pub(crate) use self::connector::Connector;
-pub(crate) use self::discover::DynamicServiceStream;
-pub(crate) use self::executor::SharedExec;
 pub(crate) use self::grpc_timeout::GrpcTimeout;
 pub(crate) use self::io::ServerIo;
 #[cfg(feature = "tls")]
-pub(crate) use self::tls::{TlsAcceptor, TlsConnector};
-pub(crate) use self::user_agent::UserAgent;
+pub(crate) use self::tls::TlsAcceptor;
+#[cfg(all(feature = "channel", feature = "tls"))]
+pub(crate) use self::tls::TlsConnector;
+#[cfg(feature = "channel")]
+pub(crate) use self::{
+    add_origin::AddOrigin, connection::Connection, connector::Connector,
+    discover::DynamicServiceStream, executor::SharedExec, user_agent::UserAgent,
+};
 
 pub use self::router::Routes;
 pub use self::router::RoutesBuilder;
diff --git a/tonic/src/transport/service/tls.rs b/tonic/src/transport/service/tls.rs
index f956132fb..c06d7a89e 100644
--- a/tonic/src/transport/service/tls.rs
+++ b/tonic/src/transport/service/tls.rs
@@ -1,3 +1,4 @@
+#[cfg(feature = "channel")]
 use super::io::BoxedIo;
 use crate::transport::{
     server::{Connected, TlsStream},
@@ -5,9 +6,14 @@ use crate::transport::{
 };
 use std::{fmt, sync::Arc};
 use tokio::io::{AsyncRead, AsyncWrite};
+#[cfg(feature = "channel")]
 use tokio_rustls::{
-    rustls::{ClientConfig, RootCertStore, ServerConfig, ServerName},
-    TlsAcceptor as RustlsAcceptor, TlsConnector as RustlsConnector,
+    rustls::{ClientConfig, ServerName},
+    TlsConnector as RustlsConnector,
+};
+use tokio_rustls::{
+    rustls::{RootCertStore, ServerConfig},
+    TlsAcceptor as RustlsAcceptor,
 };
 
 /// h2 alpn in plain format for rustls.
@@ -15,17 +21,20 @@ const ALPN_H2: &str = "h2";
 
 #[derive(Debug)]
 enum TlsError {
+    #[cfg(feature = "channel")]
     H2NotNegotiated,
     CertificateParseError,
     PrivateKeyParseError,
 }
 
+#[cfg(feature = "channel")]
 #[derive(Clone)]
 pub(crate) struct TlsConnector {
     config: Arc<ClientConfig>,
     domain: Arc<ServerName>,
 }
 
+#[cfg(feature = "channel")]
 impl TlsConnector {
     pub(crate) fn new(
         ca_cert: Option<Certificate>,
@@ -67,6 +76,7 @@ impl TlsConnector {
         })
     }
 
+    #[cfg(feature = "channel")]
     pub(crate) async fn connect<I>(&self, io: I) -> Result<BoxedIo, crate::Error>
     where
         I: AsyncRead + AsyncWrite + Send + Unpin + 'static,
@@ -90,6 +100,7 @@ impl TlsConnector {
     }
 }
 
+#[cfg(feature = "channel")]
 impl fmt::Debug for TlsConnector {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("TlsConnector").finish()
@@ -154,6 +165,7 @@ impl fmt::Debug for TlsAcceptor {
 impl fmt::Display for TlsError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
+            #[cfg(feature = "channel")]
             TlsError::H2NotNegotiated => write!(f, "HTTP/2 was not negotiated."),
             TlsError::CertificateParseError => write!(f, "Error parsing TLS certificate."),
             TlsError::PrivateKeyParseError => write!(