diff --git a/crates/synd_kvsd_protocol/src/connection.rs b/crates/synd_kvsd_protocol/src/connection.rs
index c687394..2523f57 100644
--- a/crates/synd_kvsd_protocol/src/connection.rs
+++ b/crates/synd_kvsd_protocol/src/connection.rs
@@ -7,12 +7,12 @@ use bytes::{Buf as _, BytesMut};
 use futures::TryFutureExt as _;
 use thiserror::Error;
 use tokio::{
-    io::{AsyncRead, AsyncReadExt as _, AsyncWrite, BufWriter},
+    io::{AsyncRead, AsyncReadExt as _, AsyncWrite, AsyncWriteExt as _, BufWriter},
     net::TcpStream,
     time::error::Elapsed,
 };
 
-use crate::message::{Cursor, FrameError, Message, MessageError, MessageFrames};
+use crate::message::{Cursor, Frame, FrameError, Message, MessageError, MessageFrames};
 
 #[derive(Error, Debug)]
 pub enum ConnectionError {
@@ -26,6 +26,8 @@ pub enum ConnectionError {
     ReadMessageIo { source: io::Error },
     #[error("connection reset by peer")]
     ResetByPeer,
+    #[error("write message frame: {source}")]
+    WriteMessageFrame { source: io::Error },
 }
 
 impl ConnectionError {
@@ -44,6 +46,10 @@ impl ConnectionError {
     fn read_message_io(source: io::Error) -> Self {
         ConnectionError::ReadMessageIo { source }
     }
+
+    fn write_message_frame(source: io::Error) -> Self {
+        ConnectionError::WriteMessageFrame { source }
+    }
 }
 
 pub struct Connection<Stream = TcpStream> {
@@ -64,6 +70,35 @@ where
     }
 }
 
+impl<Stream> Connection<Stream>
+where
+    Stream: AsyncWrite + Unpin,
+{
+    pub async fn write_message(&mut self, message: Message) -> Result<(), ConnectionError> {
+        let frames: MessageFrames = message.into();
+
+        // TODO: impl in Into<MessageFrames>
+        // self.stream.write_u8(prefix::MESSAGE_FRAMES).await?;
+        // self.write_decimal(frames.len()).await?;
+
+        for frame in frames {
+            self.write_frame(frame).await?;
+        }
+
+        self.stream
+            .flush()
+            .await
+            .map_err(ConnectionError::write_message_frame)
+    }
+
+    async fn write_frame(&mut self, frame: Frame) -> Result<(), ConnectionError> {
+        frame
+            .write(&mut self.stream)
+            .await
+            .map_err(ConnectionError::write_message_frame)
+    }
+}
+
 impl<Stream> Connection<Stream>
 where
     Stream: AsyncRead + Unpin,
diff --git a/crates/synd_kvsd_protocol/src/message/authenticate.rs b/crates/synd_kvsd_protocol/src/message/authenticate.rs
index 96977e3..ce977de 100644
--- a/crates/synd_kvsd_protocol/src/message/authenticate.rs
+++ b/crates/synd_kvsd_protocol/src/message/authenticate.rs
@@ -1,4 +1,7 @@
-use crate::message::parse::{Parse, ParseError};
+use crate::message::{
+    parse::{Parse, ParseError},
+    MessageFrames,
+};
 
 /// `Authenticate` is a message in which client requests the server
 /// to perform authentication process.
@@ -29,3 +32,9 @@ impl Authenticate {
         Ok(Authenticate::new(username, password))
     }
 }
+
+impl From<Authenticate> for MessageFrames {
+    fn from(_m: Authenticate) -> Self {
+        todo!()
+    }
+}
diff --git a/crates/synd_kvsd_protocol/src/message/frame.rs b/crates/synd_kvsd_protocol/src/message/frame.rs
index d382f9d..56230c6 100644
--- a/crates/synd_kvsd_protocol/src/message/frame.rs
+++ b/crates/synd_kvsd_protocol/src/message/frame.rs
@@ -1,6 +1,9 @@
+use std::io;
+
 use thiserror::Error;
+use tokio::io::AsyncWriteExt;
 
-use crate::message::{cursor::Cursor, MessageError, MessageType};
+use crate::message::{cursor::Cursor, spec, MessageError, MessageType};
 
 #[derive(Error, Debug, PartialEq, Eq)]
 pub enum FrameError {
@@ -74,6 +77,8 @@ impl Frame {
                 }
                 let value = Vec::from(&src.chunk()[..len]);
 
+                // TODO: debug assert delimiter
+
                 src.skip(n)?;
 
                 Ok(Frame::Bytes(value))
@@ -93,6 +98,52 @@ impl Frame {
             _ => unreachable!(),
         }
     }
+
+    pub(crate) async fn write<W>(self, mut writer: W) -> Result<(), io::Error>
+    where
+        W: AsyncWriteExt + Unpin,
+    {
+        match self {
+            Frame::MessageType(mt) => {
+                writer.write_u8(prefix::MESSAGE_TYPE).await?;
+                writer.write_u8(mt.into()).await
+            }
+            Frame::String(val) => {
+                writer.write_u8(prefix::STRING).await?;
+                writer.write_all(val.as_bytes()).await?;
+                writer.write_all(spec::DELIMITER).await
+            }
+            Frame::Bytes(val) => {
+                writer.write_u8(prefix::BYTES).await?;
+                Frame::write_u64(val.len() as u64, &mut writer).await?;
+                writer.write_all(val.as_ref()).await?;
+                writer.write_all(spec::DELIMITER).await
+            }
+            Frame::Time(val) => {
+                writer.write_u8(prefix::TIME).await?;
+                writer.write_all(val.to_rfc3339().as_bytes()).await?;
+                writer.write_all(spec::DELIMITER).await
+            }
+            Frame::Null => writer.write_u8(prefix::NULL).await,
+        }
+    }
+
+    // TODO: refactor
+    async fn write_u64<W>(val: u64, mut writer: W) -> io::Result<()>
+    where
+        W: AsyncWriteExt + Unpin,
+    {
+        use std::io::Write;
+
+        let mut buf = [0u8; 12];
+        let mut buf = std::io::Cursor::new(&mut buf[..]);
+        write!(&mut buf, "{val}")?;
+
+        #[allow(clippy::cast_possible_truncation)]
+        let pos = buf.position() as usize;
+        writer.write_all(&buf.get_ref()[..pos]).await?;
+        writer.write_all(spec::DELIMITER).await
+    }
 }
 
 mod prefix {
diff --git a/crates/synd_kvsd_protocol/src/message/mod.rs b/crates/synd_kvsd_protocol/src/message/mod.rs
index fdc62eb..ac35efe 100644
--- a/crates/synd_kvsd_protocol/src/message/mod.rs
+++ b/crates/synd_kvsd_protocol/src/message/mod.rs
@@ -1,5 +1,5 @@
 mod frame;
-pub(crate) use frame::{FrameError, MessageFrames};
+pub(crate) use frame::{Frame, FrameError, MessageFrames};
 
 mod authenticate;
 use authenticate::Authenticate;
@@ -65,6 +65,14 @@ pub enum Message {
     // Delete(Delete),
 }
 
+impl From<Message> for MessageFrames {
+    fn from(message: Message) -> Self {
+        match message {
+            Message::Authenticate(m) => m.into(),
+        }
+    }
+}
+
 impl Message {
     pub(crate) fn parse(frames: MessageFrames) -> Result<Message, MessageError> {
         let mut parse = Parse::new(frames);