diff --git a/src/lib.rs b/src/lib.rs
index fef562a..465e609 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,36 +2,53 @@ pub mod types;
 use crate::types::Message;
 use std::{
     collections::HashMap,
-    io::{stdin, stdout, BufRead, BufReader, Error as IoError, Stdin, Stdout, Write},
+    io::{stdin, stdout, BufRead, Error as IoError, Stdin, Stdout, Write},
     rc::Rc,
-    sync::{Arc, Mutex},
 };
 
 pub struct Malestorm<'a> {
-    stdin: Stdin,
-    pub stdout: Stdout,
+    io: MalestormIo,
+    pub handlers: HashMap<&'a str, Box<dyn Fn(Message, Rc<Malestorm>)>>,
+}
 
-    pub handlers: HashMap<&'a str, Box<dyn Fn(Message)>>,
+struct MalestormIo {
+    stdin: Stdin,
+    stdout: Stdout,
 }
 
 impl<'a> Default for Malestorm<'a> {
     fn default() -> Self {
         Self {
-            stdin: stdin(),
-            stdout: stdout(),
+            io: MalestormIo {
+                stdin: stdin(),
+                stdout: stdout(),
+            },
             handlers: HashMap::new(),
         }
     }
 }
 
+impl MalestormIo {
+    fn write(&self, buf: &[u8]) -> Result<(), IoError> {
+        let mut writer = self.stdout.lock();
+        writer.write_all(buf)?;
+        writer.flush()
+    }
+
+    fn read_line(&self, buf: &mut Vec<u8>) -> Result<usize, IoError> {
+        let mut reader = self.stdin.lock();
+
+        reader.read_until(b'\n', buf)
+    }
+}
+
 impl<'a> Malestorm<'a> {
     pub fn run(self) {
-        let mut reader = BufReader::new(self.stdin);
-
-        let mut buf = String::new();
+        let program = Rc::new(self);
 
+        let mut buf = Vec::new();
         loop {
-            let read = match reader.read_line(&mut buf) {
+            let read = match program.io.read_line(&mut buf) {
                 Ok(v) => v,
                 Err(e) => panic!("{:?}", e),
             };
@@ -40,7 +57,7 @@ impl<'a> Malestorm<'a> {
                 continue;
             }
 
-            let message: Message = match serde_json::from_str(&buf) {
+            let message: Message = match serde_json::from_slice(&buf) {
                 Ok(v) => v,
                 Err(e) => {
                     eprintln!("error in parsing input: {:?}", e);
@@ -50,7 +67,9 @@ impl<'a> Malestorm<'a> {
 
             let mtype = message.body.message_type.clone();
 
-            let handler = match self.handlers.get(&mtype.as_str()) {
+            let pc = program.clone();
+
+            let handler = match program.handlers.get(&mtype.as_str()) {
                 Some(v) => v,
                 None => {
                     eprintln!("no handler found for {}", message.body.message_type);
@@ -58,26 +77,26 @@ impl<'a> Malestorm<'a> {
                 }
             };
 
-            handler(message);
+            handler(message, pc);
         }
     }
 
-    pub fn register(&mut self, name: &'a str, func: impl Fn(Message) + 'a + 'static) {
-        self.handlers
-            .insert(name, Box::new(move |msg: Message| func(msg)));
+    pub fn register(
+        &mut self,
+        name: &'a str,
+        func: impl Fn(Message, Rc<Malestorm>) + 'a + 'static,
+    ) {
+        self.handlers.insert(name, Box::new(func));
     }
 
-    pub fn send(&self, msg: Message) -> Result<(), IoError> {
+    pub fn reply(&self, mut msg: Message) -> Result<(), IoError> {
+        // Before replying, Swap src / dst in original message
+        // Add the correct value for in_reply_to
+
+        std::mem::swap(&mut msg.src, &mut msg.dest);
+        msg.body.in_reply_to = msg.body.msg_id;
+
         let out = serde_json::to_vec(&msg)?;
-        match self.write(&out) {
-            Ok(_) => Ok(()),
-            Err(e) => Err(e),
-        }
-    }
-
-    fn write(&self, buf: &[u8]) -> Result<usize, IoError> {
-        let mut writer = self.stdout.lock();
-
-        writer.write(buf)
+        self.io.write(&out).map(|_| Ok(()))?
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 07746a8..928a715 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,44 +1,29 @@
 #![allow(special_module_name)]
 
-use std::{
-    io::{stdout, Write},
-    rc::Rc,
-    sync::{Arc, Mutex},
-};
+use std::rc::Rc;
 
 use distributed_systems_flyio::{
-    types::{EchoMessage, Message, MessageBody},
+    types::{EchoMessage, Message},
     Malestorm,
 };
 
 fn main() {
     let mut program = Malestorm::default();
 
-    let stdout = Arc::new(stdout());
+    program.register("echo", |mut msg: Message, program: Rc<Malestorm>| {
+        let message_body: EchoMessage =
+            serde_json::from_value(msg.body.message_body).expect("error in parsing message body");
 
-    let handlers = &mut program.handlers;
+        msg.body.message_type = "echo_ok".into();
+        msg.body.message_body = serde_json::to_value(message_body).unwrap();
 
-    handlers.insert(
-        "echo",
-        Box::new(move |mut msg: Message| {
-            let message_body: EchoMessage = serde_json::from_value(msg.body.message_body)
-                .expect("error in parsing message body");
-
-            msg.body.message_type = "echo_ok".into();
-            msg.body.message_body = serde_json::to_value(message_body).unwrap();
-
-            match serde_json::to_vec(&msg).map(|buf| {
-                let mut writer = stdout.lock();
-                writer.write_all(&buf).expect("error in writing content");
-                writer.flush()
-            }) {
-                Ok(_) => (),
-                Err(e) => {
-                    eprintln!("error in writing response: {}", e);
-                }
-            };
-        }),
-    );
+        match program.reply(msg) {
+            Ok(_) => (),
+            Err(e) => {
+                eprintln!("error in writing response: {}", e);
+            }
+        }
+    });
 
     program.run();
 }