diff --git a/build.sbt b/build.sbt
index 1cfff06..835cd02 100644
--- a/build.sbt
+++ b/build.sbt
@@ -32,7 +32,7 @@ lazy val root = project
       "java.classTarget" -> (baseDirectory.value / "target" / "scala-3.2.2" / "classes").toString
     ),
     Test / javaOptions ++= Seq(
-      "-Djava.library.path="++path.value("glue.target"),
+      "-Djava.library.path=" ++ path.value("glue.target")
     ),
     Compile / doc / javacOptions ++= Seq(
       "--enable-preview",
diff --git a/glue/Cargo.lock b/glue/Cargo.lock
index f81de88..7ff5d11 100644
--- a/glue/Cargo.lock
+++ b/glue/Cargo.lock
@@ -582,9 +582,9 @@ dependencies = [
 
 [[package]]
 name = "toad-jni"
-version = "0.10.1"
+version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e6f9b7ff8462ec97df69ef2bb01b485626fb43ce62a8fe33c6179f3537a9d38"
+checksum = "125f835c70283545b5840dff39d9bd132324d929041d4eaec1ed9378f08ac166"
 dependencies = [
  "embedded-time",
  "jni",
diff --git a/glue/Cargo.toml b/glue/Cargo.toml
index ce23fc2..75b4e7e 100644
--- a/glue/Cargo.toml
+++ b/glue/Cargo.toml
@@ -15,7 +15,7 @@ e2e = []
 jni = "0.21.1"
 nb = "1"
 toad = "0.17.3"
-toad-jni = "0.10.1"
+toad-jni = "0.11.0"
 no-std-net = "0.6"
 toad-msg = "0.18.1"
 tinyvec = {version = "1.5", default_features = false, features = ["rustc_1_55"]}
diff --git a/glue/src/dev/toad/ffi/uint.rs b/glue/src/dev/toad/ffi/uint.rs
index 3ef42e4..c99d2b8 100644
--- a/glue/src/dev/toad/ffi/uint.rs
+++ b/glue/src/dev/toad/ffi/uint.rs
@@ -1,6 +1,8 @@
 use core::primitive as rust;
 
-use toad_jni::java;
+use jni::objects::JObject;
+use jni::sys::{jbyteArray, jobject};
+use toad_jni::java::{self, Object};
 
 #[allow(non_camel_case_types)]
 pub struct u64(java::lang::Object);
@@ -84,3 +86,38 @@ impl u8 {
     CTOR.invoke(e, u.into())
   }
 }
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_ffi_u8_toByte<'local>(mut env: java::Env<'local>,
+                                                           u: JObject<'local>)
+                                                           -> i8 {
+  let u = java::lang::Object::from_local(&mut env, u).upcast_to::<u8>(&mut env);
+  i8::from_be_bytes([u.to_rust(&mut env).to_be()])
+}
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_ffi_u16_toBytes<'local>(mut env: java::Env<'local>,
+                                                             u: JObject<'local>)
+                                                             -> jbyteArray {
+  let u = java::lang::Object::from_local(&mut env, u).upcast_to::<u16>(&mut env);
+  let bs = u.to_rust(&mut env).to_be_bytes();
+  env.byte_array_from_slice(&bs).unwrap().as_raw()
+}
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_ffi_u32_toBytes<'local>(mut env: java::Env<'local>,
+                                                             u: JObject<'local>)
+                                                             -> jbyteArray {
+  let u = java::lang::Object::from_local(&mut env, u).upcast_to::<u32>(&mut env);
+  let bs = u.to_rust(&mut env).to_be_bytes();
+  env.byte_array_from_slice(&bs).unwrap().as_raw()
+}
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_ffi_u64_toBytes<'local>(mut env: java::Env<'local>,
+                                                             u: JObject<'local>)
+                                                             -> jbyteArray {
+  let u = java::lang::Object::from_local(&mut env, u).upcast_to::<u64>(&mut env);
+  let bs = u.to_rust(&mut env).to_be_bytes();
+  env.byte_array_from_slice(&bs).unwrap().as_raw()
+}
diff --git a/glue/src/dev/toad/mod.rs b/glue/src/dev/toad/mod.rs
index bf97eb8..a919308 100644
--- a/glue/src/dev/toad/mod.rs
+++ b/glue/src/dev/toad/mod.rs
@@ -7,9 +7,11 @@ use std::net::{Ipv4Addr, SocketAddr};
 use jni::objects::{JClass, JObject};
 use jni::sys::jobject;
 pub use retry_strategy::RetryStrategy;
+use toad::net::Addrd;
 use toad::platform::Platform;
 use toad::retry::{Attempts, Strategy};
 use toad::time::Millis;
+use toad_jni::java::net::InetSocketAddress;
 use toad_jni::java::nio::channels::{DatagramChannel, PeekableDatagramChannel};
 use toad_jni::java::{self, Object};
 
@@ -44,8 +46,7 @@ impl Toad {
   fn poll_req_impl(e: &mut java::Env, addr: i64) -> java::util::Optional<msg::ref_::Message> {
     match unsafe { Shared::deref::<Runtime>(addr).as_ref().unwrap() }.poll_req() {
       | Ok(req) => {
-        let msg_ptr: *mut toad_msg::alloc::Message =
-          unsafe { Shared::alloc_message(req.unwrap().into()) };
+        let msg_ptr = unsafe { Shared::alloc_message(req.map(Into::into)) };
         let mr = msg::ref_::Message::new(e, msg_ptr.addr() as i64);
         java::util::Optional::<msg::ref_::Message>::of(e, mr)
       },
@@ -57,6 +58,46 @@ impl Toad {
       },
     }
   }
+
+  fn poll_resp_impl(e: &mut java::Env,
+                    addr: i64,
+                    token: msg::Token,
+                    sock: InetSocketAddress)
+                    -> java::util::Optional<msg::ref_::Message> {
+    match unsafe { Shared::deref::<Runtime>(addr).as_ref().unwrap() }.poll_resp(token.to_toad(e),
+                                                                                sock.to_no_std(e))
+    {
+      | Ok(resp) => {
+        let msg_ptr = unsafe { Shared::alloc_message(resp.map(Into::into)) };
+        let mr = msg::ref_::Message::new(e, msg_ptr.addr() as i64);
+        java::util::Optional::<msg::ref_::Message>::of(e, mr)
+      },
+      | Err(nb::Error::WouldBlock) => java::util::Optional::empty(e),
+      | Err(nb::Error::Other(err)) => {
+        let err = err.downcast_ref(e).to_local(e);
+        e.throw(jni::objects::JThrowable::from(err)).unwrap();
+        java::util::Optional::<msg::ref_::Message>::empty(e)
+      },
+    }
+  }
+
+  fn send_message_impl(e: &mut java::Env,
+                       addr: i64,
+                       msg: msg::owned::Message)
+                       -> java::util::Optional<IdAndToken> {
+    match unsafe { Shared::deref::<Runtime>(addr).as_ref().unwrap() }.send_msg(Addrd(msg.to_toad(e), msg.addr(e).unwrap().to_no_std(e))) {
+      | Ok((id, token)) => {
+        let out = IdAndToken::new(e, id, token);
+        java::util::Optional::of(e, out)
+            },
+      | Err(nb::Error::WouldBlock) => java::util::Optional::empty(e),
+      | Err(nb::Error::Other(err)) => {
+        let err = err.downcast_ref(e).to_local(e);
+        e.throw(jni::objects::JThrowable::from(err)).unwrap();
+        java::util::Optional::empty(e)
+      },
+    }
+  }
 }
 
 java::object_newtype!(Toad);
@@ -65,6 +106,21 @@ impl java::Class for Toad {
   const PATH: &'static str = package!(dev.toad.Toad);
 }
 
+pub struct IdAndToken(java::lang::Object);
+
+java::object_newtype!(IdAndToken);
+impl java::Class for IdAndToken {
+  const PATH: &'static str = concat!(package!(dev.toad.Toad), "$IdAndToken");
+}
+
+impl IdAndToken {
+  pub fn new(e: &mut java::Env, id: toad_msg::Id, token: toad_msg::Token) -> Self {
+    static CTOR: java::Constructor<IdAndToken, fn(msg::Id, msg::Token)> = java::Constructor::new();
+    let (id, token) = (msg::Id::from_toad(e, id), msg::Token::from_toad(e, token));
+    CTOR.invoke(e, id, token)
+  }
+}
+
 pub struct Config(java::lang::Object);
 
 java::object_newtype!(Config);
@@ -275,6 +331,17 @@ pub extern "system" fn Java_dev_toad_Toad_init<'local>(mut e: java::Env<'local>,
   Toad::init_impl(e, cfg, channel.peekable())
 }
 
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_Toad_sendMessage<'local>(mut e: java::Env<'local>,
+                                                              _: JClass<'local>,
+                                                              addr: i64,
+                                                              msg: JObject<'local>)
+                                                              -> jobject {
+  let e = &mut e;
+  let msg: msg::owned::Message = java::lang::Object::from_local(e, msg).upcast_to(e);
+  Toad::send_message_impl(e, addr, msg).yield_to_java(e)
+}
+
 #[no_mangle]
 pub extern "system" fn Java_dev_toad_Toad_pollReq<'local>(mut e: java::Env<'local>,
                                                           _: JClass<'local>,
@@ -283,3 +350,16 @@ pub extern "system" fn Java_dev_toad_Toad_pollReq<'local>(mut e: java::Env<'loca
   let e = &mut e;
   Toad::poll_req_impl(e, addr).yield_to_java(e)
 }
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_Toad_pollResp<'local>(mut e: java::Env<'local>,
+                                                           _: JClass<'local>,
+                                                           addr: i64,
+                                                           token: JObject<'local>,
+                                                           sock: JObject<'local>)
+                                                           -> jobject {
+  let e = &mut e;
+  let token = java::lang::Object::from_local(e, token).upcast_to::<msg::Token>(e);
+  let sock = java::lang::Object::from_local(e, sock).upcast_to::<InetSocketAddress>(e);
+  Toad::poll_resp_impl(e, addr, token, sock).yield_to_java(e)
+}
diff --git a/glue/src/dev/toad/msg/code.rs b/glue/src/dev/toad/msg/code.rs
index 0da4bee..6ce3349 100644
--- a/glue/src/dev/toad/msg/code.rs
+++ b/glue/src/dev/toad/msg/code.rs
@@ -9,7 +9,7 @@ impl java::Class for Code {
 
 impl Code {
   pub fn from_toad(e: &mut java::Env, code: toad_msg::Code) -> Self {
-    static CTOR: java::Constructor<Code, fn(i16, i16)> = java::Constructor::new();
+    static CTOR: java::Constructor<Code, fn(i32, i32)> = java::Constructor::new();
     CTOR.invoke(e, code.class.into(), code.detail.into())
   }
 
diff --git a/glue/src/dev/toad/msg/id.rs b/glue/src/dev/toad/msg/id.rs
index 988ab58..22ddc7b 100644
--- a/glue/src/dev/toad/msg/id.rs
+++ b/glue/src/dev/toad/msg/id.rs
@@ -1,4 +1,6 @@
-use toad_jni::java;
+use jni::objects::JClass;
+use jni::sys::jobject;
+use toad_jni::java::{self, Object};
 
 use crate::dev::toad::ffi;
 
@@ -42,3 +44,10 @@ mod tests {
     assert_eq!(toadj.to_toad(e), toad);
   }
 }
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_msg_Id_defaultId<'local>(mut env: java::Env<'local>,
+                                                              _: JClass<'local>)
+                                                              -> jobject {
+  Id::from_toad(&mut env, toad_msg::Id(0)).yield_to_java(&mut env)
+}
diff --git a/glue/src/dev/toad/msg/mod.rs b/glue/src/dev/toad/msg/mod.rs
index 30d945c..fa48a77 100644
--- a/glue/src/dev/toad/msg/mod.rs
+++ b/glue/src/dev/toad/msg/mod.rs
@@ -1,6 +1,10 @@
+pub mod owned;
 pub mod ref_;
 
 mod ty;
+use jni::objects::JObject;
+use jni::sys::jobject;
+use toad_jni::java;
 pub use ty::Type;
 
 mod code;
diff --git a/glue/src/dev/toad/msg/owned/mod.rs b/glue/src/dev/toad/msg/owned/mod.rs
new file mode 100644
index 0000000..bb1733f
--- /dev/null
+++ b/glue/src/dev/toad/msg/owned/mod.rs
@@ -0,0 +1,8 @@
+mod msg;
+pub use msg::Message;
+
+mod opt;
+pub use opt::Opt;
+
+mod opt_value;
+pub use opt_value::OptValue;
diff --git a/glue/src/dev/toad/msg/owned/msg.rs b/glue/src/dev/toad/msg/owned/msg.rs
new file mode 100644
index 0000000..b8a320a
--- /dev/null
+++ b/glue/src/dev/toad/msg/owned/msg.rs
@@ -0,0 +1,90 @@
+use std::collections::BTreeMap;
+
+use jni::objects::JObject;
+use jni::sys::{jbyteArray, jobject};
+use toad_jni::java::net::InetSocketAddress;
+use toad_jni::java::util::ArrayList;
+use toad_jni::java::{self};
+use toad_msg::{OptNumber, TryIntoBytes};
+
+use crate::dev::toad::msg::owned::Opt;
+use crate::dev::toad::msg::{Code, Id, Token, Type};
+
+pub struct Message(java::lang::Object);
+
+java::object_newtype!(Message);
+impl java::Class for Message {
+  const PATH: &'static str = package!(dev.toad.msg.owned.Message);
+}
+
+impl Message {
+  pub fn id(&self, e: &mut java::Env) -> Id {
+    static ID: java::Field<Message, Id> = java::Field::new("id");
+    ID.get(e, self)
+  }
+
+  pub fn token(&self, e: &mut java::Env) -> Token {
+    static TOKEN: java::Field<Message, Token> = java::Field::new("token");
+    TOKEN.get(e, self)
+  }
+
+  pub fn ty(&self, e: &mut java::Env) -> Type {
+    static TY: java::Field<Message, Type> = java::Field::new("type");
+    TY.get(e, self)
+  }
+
+  pub fn code(&self, e: &mut java::Env) -> Code {
+    static CODE: java::Field<Message, Code> = java::Field::new("code");
+    CODE.get(e, self)
+  }
+
+  pub fn options(&self, e: &mut java::Env) -> Vec<Opt> {
+    static OPTIONS: java::Field<Message, ArrayList<Opt>> = java::Field::new("opts");
+    OPTIONS.get(e, self).into_iter().collect()
+  }
+
+  pub fn payload(&self, e: &mut java::Env) -> Vec<u8> {
+    static PAYLOAD: java::Field<Message, Vec<i8>> = java::Field::new("payload");
+    PAYLOAD.get(e, self)
+           .into_iter()
+           .map(|i| u8::from_be_bytes(i.to_be_bytes()))
+           .collect()
+  }
+
+  pub fn addr(&self, e: &mut java::Env) -> Option<InetSocketAddress> {
+    static ADDR: java::Field<Message, java::util::Optional<InetSocketAddress>> =
+      java::Field::new("addr");
+    ADDR.get(e, self).to_option(e)
+  }
+
+  pub fn to_toad(&self, e: &mut java::Env) -> toad_msg::alloc::Message {
+    toad_msg::Message { id: self.id(e).to_toad(e),
+                        ty: self.ty(e).to_toad(e),
+                        ver: Default::default(),
+                        token: self.token(e).to_toad(e),
+                        code: self.code(e).to_toad(e),
+                        opts:
+                          self.options(e)
+                              .into_iter()
+                              .map(|opt| {
+                                (opt.number(e),
+                                 opt.values(e)
+                                    .into_iter()
+                                    .map(|v| toad_msg::OptValue(v.bytes(e)))
+                                    .collect())
+                              })
+                              .collect::<BTreeMap<OptNumber, Vec<toad_msg::OptValue<Vec<u8>>>>>(),
+                        payload: toad_msg::Payload(self.payload(e)) }
+  }
+}
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_msg_owned_Message_toBytes<'local>(mut env: java::Env<'local>,
+                                                                       msg: JObject<'local>)
+                                                                       -> jbyteArray {
+  let jmsg = java::lang::Object::from_local(&mut env, msg).upcast_to::<Message>(&mut env);
+  let message = jmsg.to_toad(&mut env);
+  let bytes = message.try_into_bytes::<Vec<u8>>().unwrap();
+
+  env.byte_array_from_slice(&bytes).unwrap().as_raw()
+}
diff --git a/glue/src/dev/toad/msg/owned/opt.rs b/glue/src/dev/toad/msg/owned/opt.rs
new file mode 100644
index 0000000..3b9a6cf
--- /dev/null
+++ b/glue/src/dev/toad/msg/owned/opt.rs
@@ -0,0 +1,24 @@
+use toad_jni::java::util::ArrayList;
+use toad_jni::java::{self};
+use toad_msg::OptNumber;
+
+use super::OptValue;
+
+pub struct Opt(java::lang::Object);
+
+java::object_newtype!(Opt);
+impl java::Class for Opt {
+  const PATH: &'static str = package!(dev.toad.msg.owned.Option);
+}
+
+impl Opt {
+  pub fn number(&self, e: &mut java::Env) -> OptNumber {
+    static NUMBER: java::Field<Opt, crate::dev::toad::ffi::u32> = java::Field::new("number");
+    OptNumber(NUMBER.get(e, self).to_rust(e))
+  }
+
+  pub fn values(&self, e: &mut java::Env) -> Vec<OptValue> {
+    static VALUES: java::Field<Opt, ArrayList<OptValue>> = java::Field::new("values");
+    VALUES.get(e, self).into_iter().collect()
+  }
+}
diff --git a/glue/src/dev/toad/msg/owned/opt_value.rs b/glue/src/dev/toad/msg/owned/opt_value.rs
new file mode 100644
index 0000000..2f076e5
--- /dev/null
+++ b/glue/src/dev/toad/msg/owned/opt_value.rs
@@ -0,0 +1,17 @@
+use toad_jni::java;
+
+pub struct OptValue(java::lang::Object);
+java::object_newtype!(OptValue);
+impl java::Class for OptValue {
+  const PATH: &'static str = package!(dev.toad.msg.owned.OptionValue);
+}
+
+impl OptValue {
+  pub fn bytes(&self, e: &mut java::Env) -> Vec<u8> {
+    static BYTES: java::Field<OptValue, Vec<i8>> = java::Field::new("bytes");
+    BYTES.get(e, self)
+         .into_iter()
+         .map(|i| u8::from_be_bytes(i.to_be_bytes()))
+         .collect()
+  }
+}
diff --git a/glue/src/dev/toad/msg/ref_/msg.rs b/glue/src/dev/toad/msg/ref_/msg.rs
index 424581b..dd06053 100644
--- a/glue/src/dev/toad/msg/ref_/msg.rs
+++ b/glue/src/dev/toad/msg/ref_/msg.rs
@@ -2,6 +2,8 @@ use std::collections::BTreeMap;
 
 use jni::objects::JClass;
 use jni::sys::jobject;
+use toad::net::Addrd;
+use toad_jni::java::net::InetSocketAddress;
 use toad_jni::java::{self, Object};
 
 use crate::dev::toad::msg::ref_::Opt;
@@ -21,24 +23,27 @@ impl Message {
     CTOR.invoke(env, msg_addr)
   }
 
-  pub fn to_toad(&self, env: &mut java::Env) -> toad_msg::alloc::Message {
-    toad_msg::alloc::Message { ty: self.ty(env),
-                               ver: toad_msg::Version::default(),
-                               code: self.code(env),
-                               id: self.id(env),
-                               token: self.token(env),
-                               payload: toad_msg::Payload(self.payload(env)),
-                               opts: self.options(env)
-                                         .into_iter()
-                                         .map(|opt| {
-                                           (opt.number(env),
-                                            opt.values(env)
-                                               .into_iter()
-                                               .map(|v| toad_msg::OptValue(v.bytes(env)))
-                                               .collect())
-                                         })
-                                         .collect::<BTreeMap<toad_msg::OptNumber,
-                                                  Vec<toad_msg::OptValue<Vec<u8>>>>>() }
+  pub fn to_toad(&self, env: &mut java::Env) -> Addrd<toad_msg::alloc::Message> {
+    let msg = toad_msg::alloc::Message { ty: self.ty(env),
+                                         ver: toad_msg::Version::default(),
+                                         code: self.code(env),
+                                         id: self.id(env),
+                                         token: self.token(env),
+                                         payload: toad_msg::Payload(self.payload(env)),
+                                         opts: self.options(env)
+                                                   .into_iter()
+                                                   .map(|opt| {
+                                                     (opt.number(env),
+                                                      opt.values(env)
+                                                         .into_iter()
+                                                         .map(|v| toad_msg::OptValue(v.bytes(env)))
+                                                         .collect())
+                                                   })
+                                                   .collect::<BTreeMap<toad_msg::OptNumber,
+                                                            Vec<toad_msg::OptValue<Vec<u8>>>>>() };
+    Addrd(msg,
+          self.addr(env)
+              .expect("java should have made sure the address was present"))
   }
 
   pub fn close(&self, env: &mut java::Env) {
@@ -46,6 +51,14 @@ impl Message {
     CLOSE.invoke(env, self)
   }
 
+  pub fn addr(&self, env: &mut java::Env) -> Option<no_std_net::SocketAddr> {
+    static SOURCE: java::Method<Message, fn() -> java::util::Optional<InetSocketAddress>> =
+      java::Method::new("addr");
+    SOURCE.invoke(env, self)
+          .to_option(env)
+          .map(|a| a.to_no_std(env))
+  }
+
   pub fn ty(&self, env: &mut java::Env) -> toad_msg::Type {
     static TYPE: java::Method<Message, fn() -> Type> = java::Method::new("type");
     TYPE.invoke(env, self).to_toad(env)
@@ -87,10 +100,10 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_id<'local>(mut env: java::E
                                                                 -> jobject {
   let e = &mut env;
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  Id::from_toad(e, msg.id).yield_to_java(e)
+  Id::from_toad(e, msg.data().id).yield_to_java(e)
 }
 
 #[no_mangle]
@@ -100,10 +113,10 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_token<'local>(mut env: java
                                                                    -> jobject {
   let e = &mut env;
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  Token::from_toad(e, msg.token).yield_to_java(e)
+  Token::from_toad(e, msg.data().token).yield_to_java(e)
 }
 
 #[no_mangle]
@@ -112,10 +125,12 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_payload<'local>(mut env: ja
                                                                      addr: i64)
                                                                      -> jobject {
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  env.byte_array_from_slice(&msg.payload.0).unwrap().as_raw()
+  env.byte_array_from_slice(&msg.data().payload.0)
+     .unwrap()
+     .as_raw()
 }
 
 #[no_mangle]
@@ -124,10 +139,10 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_typ<'local>(mut e: java::En
                                                                  addr: i64)
                                                                  -> jobject {
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  Type::new(&mut e, msg.ty).yield_to_java(&mut e)
+  Type::new(&mut e, msg.data().ty).yield_to_java(&mut e)
 }
 
 #[no_mangle]
@@ -136,10 +151,23 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_code<'local>(mut e: java::E
                                                                   addr: i64)
                                                                   -> jobject {
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  Code::from_toad(&mut e, msg.code).yield_to_java(&mut e)
+  Code::from_toad(&mut e, msg.data().code).yield_to_java(&mut e)
+}
+
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_msg_ref_Message_addr<'local>(mut e: java::Env<'local>,
+                                                                  _: JClass<'local>,
+                                                                  addr: i64)
+                                                                  -> jobject {
+  let msg = unsafe {
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
+  };
+
+  InetSocketAddress::from_no_std(&mut e, msg.addr()).yield_to_java(&mut e)
 }
 
 #[no_mangle]
@@ -148,10 +176,10 @@ pub extern "system" fn Java_dev_toad_msg_ref_Message_opts<'local>(mut e: java::E
                                                                   addr: i64)
                                                                   -> jobject {
   let msg = unsafe {
-    Shared::deref::<toad_msg::alloc::Message>(addr).as_ref()
-                                                   .unwrap()
+    Shared::deref::<Addrd<toad_msg::alloc::Message>>(addr).as_ref()
+                                                          .unwrap()
   };
-  let opts = &msg.opts;
+  let opts = &msg.data().opts;
 
   let refs = opts.into_iter()
                  .map(|(n, v)| Opt::new(&mut e, v as *const _ as i64, n.0.into()))
@@ -182,7 +210,8 @@ mod tests {
     toad_msg.set_path("foo/bar/baz").ok();
     toad_msg.set_payload(Payload(r#"{"id": 123, "stuff": ["abc"]}"#.as_bytes().to_vec()));
 
-    let ptr: *mut toad_msg::alloc::Message = Box::into_raw(Box::new(toad_msg));
+    let ptr: *mut Addrd<toad_msg::alloc::Message> =
+      Box::into_raw(Box::new(Addrd(toad_msg, "127.0.0.1:1234".parse().unwrap())));
 
     let msg = Message::new(e, ptr.addr() as i64);
 
@@ -204,7 +233,8 @@ mod tests {
     toad_msg.set_path("foo/bar/baz").ok();
     toad_msg.set_payload(Payload(r#"{"id": 123, "stuff": ["abc"]}"#.as_bytes().to_vec()));
 
-    let ptr: *mut toad_msg::alloc::Message = Box::into_raw(Box::new(toad_msg));
+    let ptr: *mut Addrd<toad_msg::alloc::Message> =
+      Box::into_raw(Box::new(Addrd(toad_msg, "127.0.0.1:1234".parse().unwrap())));
 
     let msg = Message::new(e, ptr.addr() as i64);
 
diff --git a/glue/src/dev/toad/msg/token.rs b/glue/src/dev/toad/msg/token.rs
index 0a55ce6..5f52092 100644
--- a/glue/src/dev/toad/msg/token.rs
+++ b/glue/src/dev/toad/msg/token.rs
@@ -1,5 +1,7 @@
+use jni::objects::JClass;
+use jni::sys::jobject;
 use tinyvec::ArrayVec;
-use toad_jni::java;
+use toad_jni::java::{self, Object};
 
 use crate::dev::toad::ffi;
 
@@ -36,6 +38,13 @@ impl Token {
   }
 }
 
+#[no_mangle]
+pub extern "system" fn Java_dev_toad_msg_Token_defaultToken<'local>(mut env: java::Env<'local>,
+                                                                    _: JClass<'local>)
+                                                                    -> jobject {
+  Token::from_toad(&mut env, toad_msg::Token(Default::default())).yield_to_java(&mut env)
+}
+
 #[cfg(test)]
 mod tests {
   use tinyvec::array_vec;
diff --git a/glue/src/lib.rs b/glue/src/lib.rs
index be2f615..7198356 100644
--- a/glue/src/lib.rs
+++ b/glue/src/lib.rs
@@ -9,14 +9,12 @@ mod runtime {
   use std::collections::BTreeMap;
 
   use toad::config::Config;
-  use toad::net::Addrd;
   use toad::platform::{Effect, Platform};
-  use toad::req::Req;
-  use toad::resp::Resp;
   use toad::step::runtime::Runtime as DefaultSteps;
   use toad_jni::java::io::IOException;
-  use toad_jni::java::lang::Throwable;
+  use toad_jni::java::lang::System;
   use toad_jni::java::nio::channels::PeekableDatagramChannel;
+  use toad_jni::java::{self, Object};
   use toad_msg::{OptNumber, OptValue};
 
   #[derive(Clone, Copy, Debug)]
@@ -55,7 +53,10 @@ mod runtime {
     type Error = IOException;
 
     fn log(&self, level: log::Level, msg: toad::todo::String<1000>) -> Result<(), Self::Error> {
-      println!("[{}]: {}", level, msg.as_str());
+      let mut e = java::env();
+      let e = &mut e;
+      let (level, msg) = (level.to_string().downcast(e), msg.as_str().to_string().downcast(e));
+      System::out(e).printf(e, "[%s]: %s", vec![level, msg]);
       Ok(())
     }
 
@@ -121,26 +122,26 @@ pub mod test {
   pub fn init<'a>() -> java::Env<'a> {
     static INIT: Once = Once::new();
     INIT.call_once(|| {
-      let repo_root = Command::new("git").arg("rev-parse")
-                                         .arg("--show-toplevel")
-                                         .output()
-                                         .unwrap();
-      assert!(repo_root.status.success());
+          let repo_root = Command::new("git").arg("rev-parse")
+                                             .arg("--show-toplevel")
+                                             .output()
+                                             .unwrap();
+          assert!(repo_root.status.success());
 
-      let lib_path = String::from_utf8(repo_root.stdout).unwrap()
-                                                        .trim()
-                                                        .to_string();
-      let lib_path = PathBuf::from(lib_path).join("target/glue/debug");
+          let lib_path = String::from_utf8(repo_root.stdout).unwrap()
+                                                            .trim()
+                                                            .to_string();
+          let lib_path = PathBuf::from(lib_path).join("target/glue/debug");
 
-      let jvm =
+          let jvm =
         JavaVM::new(InitArgsBuilder::new().option(format!("-Djava.library.path={}",
                                                           lib_path.to_string_lossy()))
                                           .option("-Djava.class.path=../target/scala-3.2.2/classes")
                                           .option("--enable-preview")
                                           .build()
                                           .unwrap()).unwrap();
-      toad_jni::global::init_with(jvm);
-    });
+          toad_jni::global::init_with(jvm);
+        });
 
     let mut env = toad_jni::global::jvm().attach_current_thread_permanently()
                                          .unwrap();
diff --git a/glue/src/mem.rs b/glue/src/mem.rs
index 1022bb3..5c7d7d0 100644
--- a/glue/src/mem.rs
+++ b/glue/src/mem.rs
@@ -1,5 +1,6 @@
 use std::sync::Mutex;
 
+use toad::net::Addrd;
 use toad_msg::alloc::Message;
 
 /// global [`RuntimeAllocator`] implementation
@@ -15,10 +16,10 @@ pub trait SharedMemoryRegion: core::default::Default + core::fmt::Debug + Copy {
 
   /// Pass ownership of a [`Message`] to the shared memory region,
   /// yielding a stable pointer to this message.
-  unsafe fn alloc_message(m: Message) -> *mut Message;
+  unsafe fn alloc_message(m: Addrd<Message>) -> *mut Addrd<Message>;
 
   /// Delete a message from the shared memory region.
-  unsafe fn dealloc_message(m: *mut Message);
+  unsafe fn dealloc_message(m: *mut Addrd<Message>);
 
   /// Teardown
   unsafe fn dealloc();
@@ -38,7 +39,7 @@ static mut MEM: Mem = Mem { runtime: None,
 
 struct Mem {
   runtime: Option<crate::Runtime>,
-  messages: Vec<Message>,
+  messages: Vec<Addrd<Message>>,
 
   /// Lock used by `alloc_message` and `dealloc_message` to ensure
   /// they are run serially.
@@ -63,7 +64,7 @@ impl SharedMemoryRegion for GlobalStatic {
     MEM.runtime.as_mut().unwrap() as _
   }
 
-  unsafe fn alloc_message(m: Message) -> *mut Message {
+  unsafe fn alloc_message(m: Addrd<Message>) -> *mut Addrd<Message> {
     let Mem { ref mut messages,
               ref mut messages_lock,
               .. } = &mut MEM;
@@ -73,7 +74,7 @@ impl SharedMemoryRegion for GlobalStatic {
     &mut messages[len - 1] as _
   }
 
-  unsafe fn dealloc_message(m: *mut Message) {
+  unsafe fn dealloc_message(m: *mut Addrd<Message>) {
     let Mem { messages,
               messages_lock,
               .. } = &mut MEM;
diff --git a/src/main/java/dev.toad/Async.java b/src/main/java/dev.toad/Async.java
new file mode 100644
index 0000000..61b3af1
--- /dev/null
+++ b/src/main/java/dev.toad/Async.java
@@ -0,0 +1,39 @@
+package dev.toad;
+
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+public class Async {
+
+  public static ScheduledExecutorService executor =
+    Executors.newSingleThreadScheduledExecutor();
+
+  public static <T> CompletableFuture<T> pollCompletable(
+    Supplier<Optional<T>> sup
+  ) {
+    var fut = new CompletableFuture();
+    var pollTask = Async.executor.scheduleAtFixedRate(
+      () -> {
+        try {
+          var t = sup.get();
+          if (!t.isEmpty()) {
+            fut.complete(t.get());
+          }
+        } catch (Throwable ex) {
+          fut.completeExceptionally(ex);
+        }
+      },
+      0,
+      10,
+      TimeUnit.MILLISECONDS
+    );
+
+    return fut.whenComplete((t, err) -> {
+      pollTask.cancel(true);
+    });
+  }
+}
diff --git a/src/main/java/dev.toad/Client.java b/src/main/java/dev.toad/Client.java
index 4efa0f1..3a52ff2 100644
--- a/src/main/java/dev.toad/Client.java
+++ b/src/main/java/dev.toad/Client.java
@@ -1,10 +1,36 @@
 package dev.toad;
 
-public final class Client {
+import dev.toad.msg.Message;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+
+public final class Client implements AutoCloseable {
 
   final Toad toad;
 
   Client(Toad toad) {
     this.toad = toad;
   }
+
+  public CompletableFuture<Message> send(Message message) {
+    if (message.addr().isEmpty()) {
+      throw new IllegalArgumentException(
+        "Message destination address must be set"
+      );
+    }
+
+    return Async
+      .pollCompletable(() -> this.toad.sendMessage(message))
+      .thenCompose((Toad.IdAndToken sent) ->
+        Async.pollCompletable(() ->
+          this.toad.pollResp(sent.token, message.addr().get())
+        )
+      )
+      .thenApply(msg -> msg.toOwned());
+  }
+
+  @Override
+  public void close() {
+    this.toad.close();
+  }
 }
diff --git a/src/main/java/dev.toad/Toad.java b/src/main/java/dev.toad/Toad.java
index 917c7c2..957d0be 100644
--- a/src/main/java/dev.toad/Toad.java
+++ b/src/main/java/dev.toad/Toad.java
@@ -1,6 +1,7 @@
 package dev.toad;
 
 import dev.toad.ffi.*;
+import dev.toad.msg.*;
 import java.io.IOException;
 import java.net.DatagramSocket;
 import java.net.InetSocketAddress;
@@ -28,7 +29,7 @@ public final class Toad implements AutoCloseable {
     Toad.loadNativeLib();
   }
 
-  static void loadNativeLib() {
+  public static void loadNativeLib() {
     System.loadLibrary("toad_java_glue");
   }
 
@@ -38,6 +39,11 @@ public final class Toad implements AutoCloseable {
 
   static native long init(DatagramChannel chan, Config o);
 
+  static native Optional<IdAndToken> sendMessage(
+    long ptr,
+    dev.toad.msg.owned.Message msg
+  );
+
   static native Optional<dev.toad.msg.ref.Message> pollReq(long ptr);
 
   static native Optional<dev.toad.msg.ref.Message> pollResp(
@@ -46,12 +52,16 @@ public final class Toad implements AutoCloseable {
     InetSocketAddress n
   );
 
+  public Optional<IdAndToken> sendMessage(Message msg) {
+    return Toad.sendMessage(this.ptr.addr(), msg.toOwned());
+  }
+
   public Optional<dev.toad.msg.ref.Message> pollReq() {
     return Toad.pollReq(this.ptr.addr());
   }
 
   public Optional<dev.toad.msg.ref.Message> pollResp(
-    dev.toad.msg.Token regarding,
+    Token regarding,
     InetSocketAddress from
   ) {
     return Toad.pollResp(this.ptr.addr(), regarding, from);
@@ -76,6 +86,17 @@ public final class Toad implements AutoCloseable {
     this.ptr.release();
   }
 
+  public static final class IdAndToken {
+
+    public final Id id;
+    public final Token token;
+
+    public IdAndToken(Id id, Token token) {
+      this.id = id;
+      this.token = token;
+    }
+  }
+
   public interface BuilderRequiresSocket {
     Toad.Builder port(short port);
     Toad.Builder address(InetSocketAddress addr);
@@ -91,10 +112,11 @@ public final class Toad implements AutoCloseable {
 
     Builder() {}
 
-    public Toad build() throws IOException {
-      if (!this.ioException.isEmpty()) {
+    public Client buildClient() throws IOException {
+      if (this.ioException.isEmpty()) {
         var cfg = new Config(this.concurrency, this.msg.build());
-        return new Toad(cfg, this.channel.get());
+        var toad = new Toad(cfg, this.channel.get());
+        return new Client(toad);
       } else {
         throw this.ioException.get();
       }
diff --git a/src/main/java/dev.toad/ffi/u16.java b/src/main/java/dev.toad/ffi/u16.java
index ce4ccc8..acb2961 100644
--- a/src/main/java/dev.toad/ffi/u16.java
+++ b/src/main/java/dev.toad/ffi/u16.java
@@ -2,6 +2,8 @@ package dev.toad.ffi;
 
 public final class u16 {
 
+  public native byte[] toBytes();
+
   public static final int MAX = (int) (Math.pow(2, 16) - 1);
   private final int l;
 
diff --git a/src/main/java/dev.toad/ffi/u32.java b/src/main/java/dev.toad/ffi/u32.java
index c9a56ff..65424bf 100644
--- a/src/main/java/dev.toad/ffi/u32.java
+++ b/src/main/java/dev.toad/ffi/u32.java
@@ -2,6 +2,8 @@ package dev.toad.ffi;
 
 public final class u32 {
 
+  public native byte[] toBytes();
+
   public static final long MAX = (long) (Math.pow(2, 32) - 1);
   private final long l;
 
diff --git a/src/main/java/dev.toad/ffi/u64.java b/src/main/java/dev.toad/ffi/u64.java
index 149d6c5..a944667 100644
--- a/src/main/java/dev.toad/ffi/u64.java
+++ b/src/main/java/dev.toad/ffi/u64.java
@@ -4,6 +4,8 @@ import java.math.BigInteger;
 
 public final class u64 {
 
+  public native byte[] toBytes();
+
   public static final BigInteger MAX = BigInteger.TWO
     .pow(64)
     .subtract(BigInteger.ONE);
diff --git a/src/main/java/dev.toad/msg/Code.java b/src/main/java/dev.toad/msg/Code.java
index 5f0ed20..8f8d780 100644
--- a/src/main/java/dev.toad/msg/Code.java
+++ b/src/main/java/dev.toad/msg/Code.java
@@ -2,14 +2,45 @@ package dev.toad.msg;
 
 import dev.toad.ffi.u8;
 
-public class Code {
+public final class Code {
 
   final u8 clazz;
   final u8 detail;
 
-  public Code(short clazz, short detail) {
-    this.clazz = new u8(clazz);
-    this.detail = new u8(detail);
+  public static final Code EMPTY = new Code(0, 0);
+
+  public static final Code GET = new Code(0, 1);
+  public static final Code POST = new Code(0, 2);
+  public static final Code PUT = new Code(0, 3);
+  public static final Code DELETE = new Code(0, 4);
+
+  public static final Code OK_CREATED = new Code(2, 1);
+  public static final Code OK_DELETED = new Code(2, 2);
+  public static final Code OK_VALID = new Code(2, 3);
+  public static final Code OK_CHANGED = new Code(2, 4);
+  public static final Code OK_CONTENT = new Code(2, 5);
+
+  public static final Code BAD_REQUEST = new Code(4, 0);
+  public static final Code UNAUTHORIZED = new Code(4, 1);
+  public static final Code BAD_OPTION = new Code(4, 2);
+  public static final Code FORBIDDEN = new Code(4, 3);
+  public static final Code NOT_FOUND = new Code(4, 4);
+  public static final Code METHOD_NOT_ALLOWED = new Code(4, 5);
+  public static final Code NOT_ACCEPTABLE = new Code(4, 6);
+  public static final Code PRECONDITION_FAILED = new Code(4, 12);
+  public static final Code REQUEST_ENTITY_TOO_LARGE = new Code(4, 13);
+  public static final Code UNSUPPORTED_CONTENT_FORMAT = new Code(4, 15);
+
+  public static final Code INTERNAL_SERVER_ERROR = new Code(5, 0);
+  public static final Code NOT_IMPLEMENTED = new Code(5, 1);
+  public static final Code BAD_GATEWAY = new Code(5, 2);
+  public static final Code SERVICE_UNAVAILABLE = new Code(5, 3);
+  public static final Code GATEWAY_TIMEOUT = new Code(5, 4);
+  public static final Code PROXYING_NOT_SUPPORTED = new Code(5, 5);
+
+  public Code(int clazz, int detail) {
+    this.clazz = new u8((short) clazz);
+    this.detail = new u8((short) detail);
   }
 
   public short codeClass() {
diff --git a/src/main/java/dev.toad/msg/Id.java b/src/main/java/dev.toad/msg/Id.java
index 519ce4b..fd26f65 100644
--- a/src/main/java/dev.toad/msg/Id.java
+++ b/src/main/java/dev.toad/msg/Id.java
@@ -4,6 +4,8 @@ import dev.toad.ffi.u16;
 
 public final class Id {
 
+  public static native Id defaultId();
+
   final u16 id;
 
   public Id(int id) {
diff --git a/src/main/java/dev.toad/msg/Message.java b/src/main/java/dev.toad/msg/Message.java
index 9bae185..5aa5f04 100644
--- a/src/main/java/dev.toad/msg/Message.java
+++ b/src/main/java/dev.toad/msg/Message.java
@@ -2,9 +2,10 @@ package dev.toad.msg;
 
 import java.net.InetSocketAddress;
 import java.util.List;
+import java.util.Optional;
 
 public interface Message {
-  public InetSocketAddress source();
+  public Optional<InetSocketAddress> addr();
 
   public Id id();
 
@@ -19,4 +20,8 @@ public interface Message {
   public byte[] payloadBytes();
 
   public String payloadString();
+
+  public dev.toad.msg.owned.Message toOwned();
+
+  public byte[] toBytes();
 }
diff --git a/src/main/java/dev.toad/msg/OptionValue.java b/src/main/java/dev.toad/msg/OptionValue.java
index bdd3f53..532f0cd 100644
--- a/src/main/java/dev.toad/msg/OptionValue.java
+++ b/src/main/java/dev.toad/msg/OptionValue.java
@@ -4,4 +4,6 @@ public interface OptionValue {
   public byte[] asBytes();
 
   public String asString();
+
+  public dev.toad.msg.owned.OptionValue toOwned();
 }
diff --git a/src/main/java/dev.toad/msg/Token.java b/src/main/java/dev.toad/msg/Token.java
index 0800651..2306722 100644
--- a/src/main/java/dev.toad/msg/Token.java
+++ b/src/main/java/dev.toad/msg/Token.java
@@ -2,6 +2,8 @@ package dev.toad.msg;
 
 public final class Token {
 
+  public static native Token defaultToken();
+
   final byte[] bytes;
 
   public Token(byte[] bytes) {
diff --git a/src/main/java/dev.toad/msg/build/Message.java b/src/main/java/dev.toad/msg/build/Message.java
new file mode 100644
index 0000000..a7f22d4
--- /dev/null
+++ b/src/main/java/dev.toad/msg/build/Message.java
@@ -0,0 +1,103 @@
+package dev.toad.msg.build;
+
+import dev.toad.msg.Code;
+import dev.toad.msg.Id;
+import dev.toad.msg.Token;
+import dev.toad.msg.Type;
+import java.net.InetSocketAddress;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public final class Message
+  implements MessageNeeds.Code, MessageNeeds.Destination, MessageNeeds.Type {
+
+  HashMap<Long, ArrayList<dev.toad.msg.owned.OptionValue>> options =
+    new HashMap<>();
+  Optional<Id> id = Optional.empty();
+  Optional<Token> token = Optional.empty();
+  Optional<InetSocketAddress> addr = Optional.empty();
+  Optional<Code> code = Optional.empty();
+  Optional<Type> type = Optional.empty();
+  byte[] payload = new byte[] {};
+
+  Message() {}
+
+  public static MessageNeeds.Destination builder() {
+    return new Message();
+  }
+
+  public MessageNeeds.Type addr(InetSocketAddress addr) {
+    this.addr = Optional.of(addr);
+    return this;
+  }
+
+  public MessageNeeds.Code type(Type type) {
+    this.type = Optional.of(type);
+    return this;
+  }
+
+  public Message code(Code code) {
+    this.code = Optional.of(code);
+    return this;
+  }
+
+  public Message id(Id id) {
+    this.id = Optional.of(id);
+    return this;
+  }
+
+  public Message token(Token token) {
+    this.token = Optional.of(token);
+    return this;
+  }
+
+  public Message option(
+    Function<OptionNeeds.Number, dev.toad.msg.owned.Option> fun
+  ) {
+    var opt = fun.apply(Option.builder());
+    return this.option(opt);
+  }
+
+  public Message option(dev.toad.msg.Option opt) {
+    return this.option(opt.number(), opt.values());
+  }
+
+  public Message option(long number, List<dev.toad.msg.OptionValue> values) {
+    if (this.options.get(number) == null) {
+      this.options.put(number, new ArrayList<>());
+    }
+
+    this.options.get(number)
+      .addAll(values.stream().map(v -> v.toOwned()).toList());
+    return this;
+  }
+
+  public Message payload(String payload) {
+    this.payload = payload.getBytes();
+    return this;
+  }
+
+  public Message payload(byte[] payload) {
+    this.payload = payload;
+    return this;
+  }
+
+  public dev.toad.msg.Message build() {
+    return new dev.toad.msg.owned.Message(
+      this.addr,
+      this.type.get(),
+      this.code.get(),
+      this.id.orElse(Id.defaultId()),
+      this.token.orElse(Token.defaultToken()),
+      this.payload,
+      this.options.entrySet()
+        .stream()
+        .map(ent -> new dev.toad.msg.owned.Option(ent.getKey(), ent.getValue()))
+        .collect(Collectors.toCollection(() -> new ArrayList<>()))
+    );
+  }
+}
diff --git a/src/main/java/dev.toad/msg/build/MessageNeeds.java b/src/main/java/dev.toad/msg/build/MessageNeeds.java
new file mode 100644
index 0000000..b5bdc76
--- /dev/null
+++ b/src/main/java/dev.toad/msg/build/MessageNeeds.java
@@ -0,0 +1,18 @@
+package dev.toad.msg.build;
+
+import java.net.InetSocketAddress;
+
+public final class MessageNeeds {
+
+  public interface Destination {
+    MessageNeeds.Type addr(InetSocketAddress addr);
+  }
+
+  public interface Type {
+    MessageNeeds.Code type(dev.toad.msg.Type type);
+  }
+
+  public interface Code {
+    Message code(dev.toad.msg.Code code);
+  }
+}
diff --git a/src/main/java/dev.toad/msg/build/Option.java b/src/main/java/dev.toad/msg/build/Option.java
new file mode 100644
index 0000000..6c0a82b
--- /dev/null
+++ b/src/main/java/dev.toad/msg/build/Option.java
@@ -0,0 +1,36 @@
+package dev.toad.msg.build;
+
+import java.util.ArrayList;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+public final class Option implements OptionNeeds.Number {
+
+  Optional<Long> number = Optional.empty();
+  ArrayList<byte[]> values = new ArrayList<>();
+
+  Option() {}
+
+  public static OptionNeeds.Number builder() {
+    return new Option();
+  }
+
+  public Option number(long num) {
+    this.number = Optional.of(num);
+    return this;
+  }
+
+  public Option addValue(byte[] bytes) {
+    this.values.add(bytes);
+    return this;
+  }
+
+  public dev.toad.msg.owned.Option build() {
+    return new dev.toad.msg.owned.Option(
+      this.number.get(),
+      this.values.stream()
+        .map(bytes -> new dev.toad.msg.owned.OptionValue(bytes))
+        .collect(Collectors.toCollection(() -> new ArrayList<>()))
+    );
+  }
+}
diff --git a/src/main/java/dev.toad/msg/build/OptionNeeds.java b/src/main/java/dev.toad/msg/build/OptionNeeds.java
new file mode 100644
index 0000000..bf73817
--- /dev/null
+++ b/src/main/java/dev.toad/msg/build/OptionNeeds.java
@@ -0,0 +1,8 @@
+package dev.toad.msg.build;
+
+public final class OptionNeeds {
+
+  public interface Number {
+    Option number(long num);
+  }
+}
diff --git a/src/main/java/dev.toad/msg/option/Accept.java b/src/main/java/dev.toad/msg/option/Accept.java
new file mode 100644
index 0000000..8215227
--- /dev/null
+++ b/src/main/java/dev.toad/msg/option/Accept.java
@@ -0,0 +1,29 @@
+package dev.toad.msg.option;
+
+import dev.toad.ffi.u16;
+import dev.toad.msg.Option;
+import dev.toad.msg.OptionValue;
+import java.util.ArrayList;
+import java.util.List;
+
+public final class Accept extends ContentFormat implements Option {
+
+  public static final Accept TEXT = new Accept(ContentFormat.TEXT);
+  public static final Accept LINK_FORMAT = new Accept(
+    ContentFormat.LINK_FORMAT
+  );
+  public static final Accept XML = new Accept(ContentFormat.XML);
+  public static final Accept OCTET_STREAM = new Accept(
+    ContentFormat.OCTET_STREAM
+  );
+  public static final Accept EXI = new Accept(ContentFormat.EXI);
+  public static final Accept JSON = new Accept(ContentFormat.JSON);
+
+  Accept(int value) {
+    super(value);
+  }
+
+  public Accept(ContentFormat format) {
+    this(format.value());
+  }
+}
diff --git a/src/main/java/dev.toad/msg/option/ContentFormat.java b/src/main/java/dev.toad/msg/option/ContentFormat.java
new file mode 100644
index 0000000..70a2ccf
--- /dev/null
+++ b/src/main/java/dev.toad/msg/option/ContentFormat.java
@@ -0,0 +1,45 @@
+package dev.toad.msg.option;
+
+import dev.toad.ffi.u16;
+import dev.toad.msg.Option;
+import dev.toad.msg.OptionValue;
+import java.util.ArrayList;
+import java.util.List;
+
+public sealed class ContentFormat implements Option permits Accept {
+
+  final u16 value;
+
+  ContentFormat(int value) {
+    this.value = new u16(value);
+  }
+
+  public static final ContentFormat TEXT = ContentFormat.custom(0);
+  public static final ContentFormat LINK_FORMAT = ContentFormat.custom(40);
+  public static final ContentFormat XML = ContentFormat.custom(41);
+  public static final ContentFormat OCTET_STREAM = ContentFormat.custom(42);
+  public static final ContentFormat EXI = ContentFormat.custom(47);
+  public static final ContentFormat JSON = ContentFormat.custom(50);
+
+  public static ContentFormat custom(int value) {
+    return new ContentFormat(value);
+  }
+
+  public boolean equals(ContentFormat other) {
+    return this.value == other.value;
+  }
+
+  public long number() {
+    return 12;
+  }
+
+  public int value() {
+    return this.value.intValue();
+  }
+
+  public List<OptionValue> values() {
+    var list = new ArrayList<OptionValue>();
+    list.add(new dev.toad.msg.owned.OptionValue(this.value.toBytes()));
+    return list;
+  }
+}
diff --git a/src/main/java/dev.toad/msg/owned/Message.java b/src/main/java/dev.toad/msg/owned/Message.java
index c0279e8..7758142 100644
--- a/src/main/java/dev.toad/msg/owned/Message.java
+++ b/src/main/java/dev.toad/msg/owned/Message.java
@@ -5,28 +5,31 @@ import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 public class Message implements dev.toad.msg.Message {
 
-  final InetSocketAddress source;
+  public native byte[] toBytes();
+
+  final Optional<InetSocketAddress> addr;
   final Id id;
   final Token token;
   final byte[] payload;
   final Code code;
   final Type type;
-  final List<dev.toad.msg.Option> opts;
+  final ArrayList<dev.toad.msg.owned.Option> opts;
 
   public Message(
-    InetSocketAddress source,
+    Optional<InetSocketAddress> addr,
     Type type,
     Code code,
     Id id,
     Token token,
     byte[] payload,
-    List<dev.toad.msg.Option> opts
+    ArrayList<dev.toad.msg.owned.Option> opts
   ) {
-    this.source = source;
+    this.addr = addr;
     this.id = id;
     this.token = token;
     this.payload = payload;
@@ -37,7 +40,7 @@ public class Message implements dev.toad.msg.Message {
 
   public Message(dev.toad.msg.ref.Message ref) {
     this(
-      ref.source(),
+      ref.addr(),
       ref.type(),
       ref.code(),
       ref.id(),
@@ -46,13 +49,17 @@ public class Message implements dev.toad.msg.Message {
       Arrays
         .asList(ref.optionRefs())
         .stream()
-        .map(dev.toad.msg.ref.Option::clone)
-        .collect(Collectors.toList())
+        .map(dev.toad.msg.ref.Option::toOwned)
+        .collect(Collectors.toCollection(() -> new ArrayList<>()))
     );
   }
 
-  public InetSocketAddress source() {
-    return this.source;
+  public Message toOwned() {
+    return this;
+  }
+
+  public Optional<InetSocketAddress> addr() {
+    return this.addr;
   }
 
   public Id id() {
@@ -72,7 +79,7 @@ public class Message implements dev.toad.msg.Message {
   }
 
   public List<dev.toad.msg.Option> options() {
-    return this.opts;
+    return List.copyOf(this.opts);
   }
 
   public byte[] payloadBytes() {
diff --git a/src/main/java/dev.toad/msg/owned/Option.java b/src/main/java/dev.toad/msg/owned/Option.java
index ca94e5e..25bcf3f 100644
--- a/src/main/java/dev.toad/msg/owned/Option.java
+++ b/src/main/java/dev.toad/msg/owned/Option.java
@@ -1,17 +1,19 @@
 package dev.toad.msg.owned;
 
+import dev.toad.ffi.u32;
 import dev.toad.msg.*;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 
 public class Option implements dev.toad.msg.Option {
 
-  final long number;
-  final List<dev.toad.msg.OptionValue> values;
+  final u32 number;
+  final ArrayList<dev.toad.msg.owned.OptionValue> values;
 
-  public Option(long number, List<dev.toad.msg.OptionValue> values) {
-    this.number = number;
+  public Option(long number, ArrayList<dev.toad.msg.owned.OptionValue> values) {
+    this.number = new u32(number);
     this.values = values;
   }
 
@@ -21,16 +23,16 @@ public class Option implements dev.toad.msg.Option {
       Arrays
         .asList(ref.valueRefs())
         .stream()
-        .map(dev.toad.msg.ref.OptionValue::clone)
-        .collect(Collectors.toList())
+        .map(dev.toad.msg.ref.OptionValue::toOwned)
+        .collect(Collectors.toCollection(() -> new ArrayList<>()))
     );
   }
 
   public long number() {
-    return this.number;
+    return this.number.longValue();
   }
 
   public List<dev.toad.msg.OptionValue> values() {
-    return this.values;
+    return List.copyOf(this.values);
   }
 }
diff --git a/src/main/java/dev.toad/msg/owned/OptionValue.java b/src/main/java/dev.toad/msg/owned/OptionValue.java
index 1fc9cab..ce4f0f7 100644
--- a/src/main/java/dev.toad/msg/owned/OptionValue.java
+++ b/src/main/java/dev.toad/msg/owned/OptionValue.java
@@ -19,4 +19,8 @@ public class OptionValue implements dev.toad.msg.OptionValue {
   public String asString() {
     return new String(this.asBytes());
   }
+
+  public dev.toad.msg.owned.OptionValue toOwned() {
+    return this;
+  }
 }
diff --git a/src/main/java/dev.toad/msg/ref/Message.java b/src/main/java/dev.toad/msg/ref/Message.java
index 63848af..2db4391 100644
--- a/src/main/java/dev.toad/msg/ref/Message.java
+++ b/src/main/java/dev.toad/msg/ref/Message.java
@@ -18,9 +18,9 @@ public final class Message implements dev.toad.msg.Message, AutoCloseable {
 
   Ptr ptr;
 
-  Optional<InetSocketAddress> source = Optional.empty();
+  Optional<InetSocketAddress> addr = Optional.empty();
 
-  static native InetSocketAddress source(long addr);
+  static native InetSocketAddress addr(long addr);
 
   static native Id id(long addr);
 
@@ -34,20 +34,22 @@ public final class Message implements dev.toad.msg.Message, AutoCloseable {
 
   static native dev.toad.msg.ref.Option[] opts(long addr);
 
+  static native byte[] toBytes(long addr);
+
   Message(long addr) {
     this.ptr = Ptr.register(this.getClass(), addr);
   }
 
-  public dev.toad.msg.Message clone() {
+  public dev.toad.msg.owned.Message toOwned() {
     return new dev.toad.msg.owned.Message(this);
   }
 
-  public InetSocketAddress source() {
-    if (this.source.isEmpty()) {
-      this.source = Optional.of(this.source(this.ptr.addr()));
+  public Optional<InetSocketAddress> addr() {
+    if (this.addr.isEmpty()) {
+      this.addr = Optional.of(this.addr(this.ptr.addr()));
     }
 
-    return this.source.get();
+    return this.addr;
   }
 
   public Id id() {
@@ -82,6 +84,10 @@ public final class Message implements dev.toad.msg.Message, AutoCloseable {
     return new String(this.payload(this.ptr.addr()));
   }
 
+  public byte[] toBytes() {
+    return this.toBytes(this.ptr.addr());
+  }
+
   @Override
   public void close() {
     this.ptr.release();
diff --git a/src/main/java/dev.toad/msg/ref/Option.java b/src/main/java/dev.toad/msg/ref/Option.java
index a6ab620..bfcb7d4 100644
--- a/src/main/java/dev.toad/msg/ref/Option.java
+++ b/src/main/java/dev.toad/msg/ref/Option.java
@@ -29,7 +29,7 @@ public class Option implements dev.toad.msg.Option, AutoCloseable {
     return Arrays.asList(this.values(this.ptr.addr()));
   }
 
-  public dev.toad.msg.Option clone() {
+  public dev.toad.msg.owned.Option toOwned() {
     return new dev.toad.msg.owned.Option(this);
   }
 
diff --git a/src/main/java/dev.toad/msg/ref/OptionValue.java b/src/main/java/dev.toad/msg/ref/OptionValue.java
index 3483cbd..96e0b3c 100644
--- a/src/main/java/dev.toad/msg/ref/OptionValue.java
+++ b/src/main/java/dev.toad/msg/ref/OptionValue.java
@@ -21,7 +21,7 @@ public final class OptionValue
     return new String(this.bytes(this.ptr.addr()));
   }
 
-  public dev.toad.msg.OptionValue clone() {
+  public dev.toad.msg.owned.OptionValue toOwned() {
     return new dev.toad.msg.owned.OptionValue(this);
   }
 
diff --git a/src/test/java/Mock.java b/src/test/java/Mock.java
index d7c2387..6522273 100644
--- a/src/test/java/Mock.java
+++ b/src/test/java/Mock.java
@@ -97,7 +97,6 @@ public class Mock {
           return ent.getKey();
         }
       }
-
       return null;
     }
 
diff --git a/src/test/scala/Async.scala b/src/test/scala/Async.scala
new file mode 100644
index 0000000..96d6566
--- /dev/null
+++ b/src/test/scala/Async.scala
@@ -0,0 +1,49 @@
+import dev.toad.Async
+import java.util.Optional
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.CompletableFuture
+
+class AsyncTest extends munit.FunSuite {
+  test("pollCompletable polls then completes") {
+    var polls = 0
+
+    val fut = Async.pollCompletable(() => {
+      polls = polls + 1
+      if polls == 10 then {
+        Optional.of(true)
+      } else {
+        Optional.empty
+      }
+    })
+
+    fut.get(200, TimeUnit.MILLISECONDS)
+  }
+
+  test("pollCompletable does not poll after completion") {
+    var polls = 0
+    val fut = Async.pollCompletable(() => {
+      polls = polls + 1
+      Optional.of(true)
+    })
+
+    fut.get()
+
+    Thread.sleep(100)
+    assertEquals(polls, 1)
+  }
+
+  test("pollCompletable completesExceptionally when poll throws") {
+    val err = Async
+      .pollCompletable[Object](() => throw Exception("foo"))
+      .handle((ok, e) => {
+        if ok != null then {
+          "CompletableFuture was completed without exception"
+        } else {
+          e.getMessage
+        }
+      })
+      .get()
+
+    assertEquals(err, "java.lang.Exception: foo")
+  }
+}
diff --git a/src/test/scala/E2E.scala b/src/test/scala/E2E.scala
index 62b4ed7..ef148ca 100644
--- a/src/test/scala/E2E.scala
+++ b/src/test/scala/E2E.scala
@@ -1,10 +1,60 @@
-import dev.toad.*;
-import mock.java.nio.channels.Mock;
+import dev.toad.*
+import dev.toad.msg.*
+import dev.toad.msg.option.ContentFormat
+import dev.toad.msg.option.Accept
+import mock.java.nio.channels.Mock
+import java.net.InetSocketAddress
+import java.util.ArrayList
+import java.nio.ByteBuffer
+import java.util.concurrent.TimeUnit
 
 class E2E extends munit.FunSuite {
-  test("foo") {
+  test("minimal client and server") {
+    Toad.loadNativeLib()
+
     val mock = Mock.Channel()
-    val toad = Toad.builder.channel(mock).build
-    val req = Option.apply(toad.pollReq.get)
+
+    val ack = dev.toad.msg.build.Message
+      .builder()
+      .addr(InetSocketAddress("127.0.0.1", 1111))
+      .`type`(Type.ACK)
+      .code(Code.EMPTY)
+      .id(Id(2))
+      .token(Token(Array(1)))
+      .option(ContentFormat.TEXT)
+      .payload("foobar")
+      .build
+
+    val resp = dev.toad.msg.build.Message
+      .builder()
+      .addr(InetSocketAddress("127.0.0.1", 1111))
+      .`type`(Type.NON)
+      .code(Code.OK_CONTENT)
+      .id(Id(3))
+      .token(Token(Array(1)))
+      .option(ContentFormat.TEXT)
+      .payload("foobar")
+      .build
+
+    val req = dev.toad.msg.build.Message
+      .builder()
+      .addr(InetSocketAddress("127.0.0.1", 2222))
+      .`type`(Type.CON)
+      .code(Code(2, 4))
+      .id(Id(1))
+      .token(Token(Array(1)))
+      .option(Accept.TEXT)
+      .build
+
+    val client = Toad.builder.channel(mock).buildClient
+    val respFuture = client.send(req)
+
+    var bufs = ArrayList[ByteBuffer]()
+    bufs.add(ByteBuffer.wrap(resp.toBytes()))
+    mock.recv.put(InetSocketAddress("127.0.0.1", 2222), bufs)
+
+    val respActual = respFuture.get(1, TimeUnit.SECONDS)
+
+    assertEquals(resp.payloadBytes().toSeq, respActual.payloadBytes().toSeq)
   }
 }
diff --git a/src/test/scala/Glue.scala b/src/test/scala/Glue.scala
index b236720..a917f62 100644
--- a/src/test/scala/Glue.scala
+++ b/src/test/scala/Glue.scala
@@ -2,6 +2,10 @@ import sys.process._
 
 class Glue extends munit.FunSuite {
   test("cargo test") {
-    Seq("sh", "-c", "cd glue; RUST_BACKTRACE=full cargo test --quiet --features e2e").!!
+    Seq(
+      "sh",
+      "-c",
+      "cd glue; RUST_BACKTRACE=full cargo test --quiet --features e2e"
+    ).!!
   }
 }