diff --git a/openless-all/app/src-tauri/src/lib.rs b/openless-all/app/src-tauri/src/lib.rs
index 3210c9db..9bc92e98 100644
--- a/openless-all/app/src-tauri/src/lib.rs
+++ b/openless-all/app/src-tauri/src/lib.rs
@@ -20,6 +20,7 @@ mod persistence;
 mod polish;
 mod recorder;
 mod types;
+mod windows_ime_ipc;
 mod windows_ime_profile;
 mod windows_ime_protocol;
 
diff --git a/openless-all/app/src-tauri/src/windows_ime_ipc.rs b/openless-all/app/src-tauri/src/windows_ime_ipc.rs
new file mode 100644
index 00000000..3fe8b0c3
--- /dev/null
+++ b/openless-all/app/src-tauri/src/windows_ime_ipc.rs
@@ -0,0 +1,365 @@
+use std::time::Duration;
+
+use crate::windows_ime_protocol::ImeSubmitStatus;
+
+pub const IME_CLIENT_WAIT_TIMEOUT: Duration = Duration::from_millis(700);
+pub const IME_SUBMIT_TIMEOUT: Duration = Duration::from_millis(900);
+const IME_PIPE_RETRY_INTERVAL: Duration = Duration::from_millis(25);
+
+const ERROR_FILE_NOT_FOUND: u32 = 2;
+const ERROR_PATH_NOT_FOUND: u32 = 3;
+const ERROR_SEM_TIMEOUT: u32 = 121;
+const ERROR_PIPE_BUSY: u32 = 231;
+const NMPWAIT_NOWAIT: u32 = 0x00000001;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum WindowsImeIpcError {
+    Unavailable(String),
+    NoReadyClient,
+    Timeout,
+    Protocol(String),
+    Io(String),
+}
+
+impl std::fmt::Display for WindowsImeIpcError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Unavailable(message) | Self::Protocol(message) | Self::Io(message) => {
+                write!(f, "{message}")
+            }
+            Self::NoReadyClient => write!(f, "no OpenLess IME client is ready"),
+            Self::Timeout => write!(f, "OpenLess IME IPC timed out"),
+        }
+    }
+}
+
+impl std::error::Error for WindowsImeIpcError {}
+
+pub type WindowsImeIpcResult<T> = Result<T, WindowsImeIpcError>;
+
+fn map_wait_named_pipe_error(error_code: Option<u32>) -> WindowsImeIpcError {
+    match error_code {
+        Some(ERROR_FILE_NOT_FOUND | ERROR_PATH_NOT_FOUND | ERROR_PIPE_BUSY) => {
+            WindowsImeIpcError::NoReadyClient
+        }
+        Some(ERROR_SEM_TIMEOUT) => WindowsImeIpcError::Timeout,
+        Some(code) => WindowsImeIpcError::Io(format!("WaitNamedPipeW failed with OS error {code}")),
+        None => WindowsImeIpcError::Io("WaitNamedPipeW failed without OS error".to_string()),
+    }
+}
+
+fn is_retryable_pipe_error(error_code: Option<u32>) -> bool {
+    matches!(
+        error_code,
+        Some(ERROR_FILE_NOT_FOUND | ERROR_PATH_NOT_FOUND | ERROR_PIPE_BUSY | ERROR_SEM_TIMEOUT)
+    )
+}
+
+#[derive(Debug)]
+pub struct PendingImeSubmit {
+    session_id: String,
+    completed: bool,
+}
+
+impl PendingImeSubmit {
+    pub fn new(session_id: String) -> Self {
+        Self {
+            session_id,
+            completed: false,
+        }
+    }
+
+    pub fn accept_result(
+        &mut self,
+        session_id: &str,
+        status: ImeSubmitStatus,
+    ) -> WindowsImeIpcResult<ImeSubmitStatus> {
+        if self.completed {
+            return Err(WindowsImeIpcError::Protocol(
+                "submit result arrived after completion".to_string(),
+            ));
+        }
+        if self.session_id != session_id {
+            return Err(WindowsImeIpcError::Protocol(
+                "submit result belongs to a different session".to_string(),
+            ));
+        }
+        self.completed = true;
+        Ok(status)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct ImeSubmitRequest {
+    pub session_id: String,
+    pub text: String,
+    pub created_at: String,
+}
+
+#[derive(Clone)]
+pub struct WindowsImeIpcServer {
+    inner: std::sync::Arc<parking_lot::Mutex<WindowsImeIpcState>>,
+}
+
+#[derive(Debug, Default)]
+struct WindowsImeIpcState {
+    ready_client_id: Option<String>,
+}
+
+impl WindowsImeIpcServer {
+    pub fn new() -> Self {
+        Self {
+            inner: std::sync::Arc::new(parking_lot::Mutex::new(WindowsImeIpcState::default())),
+        }
+    }
+
+    pub fn mark_client_ready_for_test(&self, client_id: String) {
+        self.inner.lock().ready_client_id = Some(client_id);
+    }
+
+    pub fn has_ready_client(&self) -> bool {
+        self.inner.lock().ready_client_id.is_some()
+    }
+
+    pub async fn submit_text(
+        &self,
+        request: ImeSubmitRequest,
+    ) -> WindowsImeIpcResult<ImeSubmitStatus> {
+        #[cfg(target_os = "windows")]
+        {
+            let _ = self;
+            submit_text_to_platform(request).await
+        }
+
+        #[cfg(not(target_os = "windows"))]
+        {
+            let _ = self;
+            let _ = request;
+            Err(WindowsImeIpcError::Unavailable(
+                "OpenLess IME IPC is only available on Windows".to_string(),
+            ))
+        }
+    }
+}
+
+impl Default for WindowsImeIpcServer {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(target_os = "windows")]
+async fn submit_text_to_platform(
+    request: ImeSubmitRequest,
+) -> WindowsImeIpcResult<ImeSubmitStatus> {
+    windows_pipe::submit_text_over_pipe(request).await
+}
+
+#[cfg(target_os = "windows")]
+mod windows_pipe {
+    use std::ffi::OsStr;
+    use std::os::windows::ffi::OsStrExt;
+    use std::time::Instant;
+
+    use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+    use tokio::net::windows::named_pipe::{ClientOptions, NamedPipeClient};
+
+    use super::{
+        ImeSubmitRequest, PendingImeSubmit, WindowsImeIpcError, WindowsImeIpcResult,
+        IME_CLIENT_WAIT_TIMEOUT, IME_PIPE_RETRY_INTERVAL, IME_SUBMIT_TIMEOUT,
+    };
+    use crate::windows_ime_protocol::{
+        decode_message, encode_message, ImePipeMessage, OPENLESS_IME_PIPE_NAME,
+        OPENLESS_IME_PROTOCOL_VERSION,
+    };
+
+    extern "system" {
+        fn WaitNamedPipeW(lpNamedPipeName: *const u16, nTimeOut: u32) -> i32;
+    }
+
+    pub async fn submit_text_over_pipe(
+        request: ImeSubmitRequest,
+    ) -> WindowsImeIpcResult<crate::windows_ime_protocol::ImeSubmitStatus> {
+        let mut pending = PendingImeSubmit::new(request.session_id.clone());
+        let pipe = open_pipe_with_retry().await?;
+        let (read_half, mut write_half) = tokio::io::split(pipe);
+        let mut reader = BufReader::new(read_half);
+
+        let message = ImePipeMessage::SubmitText {
+            protocol_version: OPENLESS_IME_PROTOCOL_VERSION,
+            session_id: request.session_id,
+            text: request.text,
+            created_at: request.created_at,
+        };
+        let line = encode_message(&message)
+            .map_err(|error| WindowsImeIpcError::Protocol(error.to_string()))?;
+
+        let response = tokio::time::timeout(IME_SUBMIT_TIMEOUT, async {
+            write_half
+                .write_all(line.as_bytes())
+                .await
+                .map_err(|error| WindowsImeIpcError::Io(error.to_string()))?;
+            write_half
+                .flush()
+                .await
+                .map_err(|error| WindowsImeIpcError::Io(error.to_string()))?;
+
+            let mut response = String::new();
+            let bytes_read = reader
+                .read_line(&mut response)
+                .await
+                .map_err(|error| WindowsImeIpcError::Io(error.to_string()))?;
+
+            if bytes_read == 0 {
+                return Err(WindowsImeIpcError::Io(
+                    "IME pipe closed before submit result".to_string(),
+                ));
+            }
+
+            Ok(response)
+        })
+        .await
+        .map_err(|_| WindowsImeIpcError::Timeout)??;
+
+        match decode_message(response.trim_end())
+            .map_err(|error| WindowsImeIpcError::Protocol(error.to_string()))?
+        {
+            ImePipeMessage::SubmitResult {
+                protocol_version,
+                session_id,
+                status,
+                ..
+            } if protocol_version == OPENLESS_IME_PROTOCOL_VERSION => {
+                pending.accept_result(&session_id, status)
+            }
+            ImePipeMessage::SubmitResult {
+                protocol_version, ..
+            } => Err(WindowsImeIpcError::Protocol(format!(
+                "unsupported IME protocol version {protocol_version}"
+            ))),
+            _ => Err(WindowsImeIpcError::Protocol(
+                "message is not a submit result".to_string(),
+            )),
+        }
+    }
+
+    async fn open_pipe_with_retry() -> WindowsImeIpcResult<NamedPipeClient> {
+        let deadline = Instant::now() + IME_CLIENT_WAIT_TIMEOUT;
+
+        loop {
+            let retry_error = match wait_for_pipe_client() {
+                Ok(()) => match ClientOptions::new().open(OPENLESS_IME_PIPE_NAME) {
+                    Ok(pipe) => return Ok(pipe),
+                    Err(error) => {
+                        let error_code = error.raw_os_error().map(|code| code as u32);
+                        if !super::is_retryable_pipe_error(error_code) {
+                            return Err(WindowsImeIpcError::Io(error.to_string()));
+                        }
+                        super::map_wait_named_pipe_error(error_code)
+                    }
+                },
+                Err(error) => {
+                    if !is_retryable_wait_error(&error) {
+                        return Err(error);
+                    }
+                    error
+                }
+            };
+
+            if Instant::now() >= deadline {
+                return Err(retry_error);
+            }
+            tokio::time::sleep(next_retry_delay(deadline)).await;
+        }
+    }
+
+    fn wait_for_pipe_client() -> WindowsImeIpcResult<()> {
+        let pipe_name = OsStr::new(OPENLESS_IME_PIPE_NAME)
+            .encode_wide()
+            .chain(std::iter::once(0))
+            .collect::<Vec<u16>>();
+
+        let is_ready = unsafe { WaitNamedPipeW(pipe_name.as_ptr(), super::NMPWAIT_NOWAIT) };
+        if is_ready != 0 {
+            return Ok(());
+        }
+
+        Err(super::map_wait_named_pipe_error(
+            std::io::Error::last_os_error()
+                .raw_os_error()
+                .map(|code| code as u32),
+        ))
+    }
+
+    fn is_retryable_wait_error(error: &WindowsImeIpcError) -> bool {
+        matches!(
+            error,
+            WindowsImeIpcError::NoReadyClient | WindowsImeIpcError::Timeout
+        )
+    }
+
+    fn next_retry_delay(deadline: Instant) -> std::time::Duration {
+        deadline
+            .saturating_duration_since(Instant::now())
+            .min(IME_PIPE_RETRY_INTERVAL)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn pending_submit_accepts_only_matching_session() {
+        let mut pending = PendingImeSubmit::new("session-1".to_string());
+        assert!(pending
+            .accept_result("session-2", ImeSubmitStatus::Committed)
+            .is_err());
+        assert_eq!(
+            pending.accept_result("session-1", ImeSubmitStatus::Committed),
+            Ok(ImeSubmitStatus::Committed)
+        );
+    }
+
+    #[test]
+    fn pending_submit_rejects_second_result_after_completion() {
+        let mut pending = PendingImeSubmit::new("session-1".to_string());
+        assert_eq!(
+            pending.accept_result("session-1", ImeSubmitStatus::Committed),
+            Ok(ImeSubmitStatus::Committed)
+        );
+        assert!(pending
+            .accept_result("session-1", ImeSubmitStatus::Committed)
+            .is_err());
+    }
+
+    #[test]
+    fn wait_pipe_error_mapping_treats_missing_or_busy_pipe_as_no_ready_client() {
+        assert_eq!(
+            map_wait_named_pipe_error(Some(2)),
+            WindowsImeIpcError::NoReadyClient
+        );
+        assert_eq!(
+            map_wait_named_pipe_error(Some(231)),
+            WindowsImeIpcError::NoReadyClient
+        );
+    }
+
+    #[test]
+    fn wait_pipe_error_mapping_treats_wait_timeout_as_timeout() {
+        assert_eq!(
+            map_wait_named_pipe_error(Some(121)),
+            WindowsImeIpcError::Timeout
+        );
+    }
+
+    #[test]
+    fn missing_busy_and_timeout_pipe_errors_are_retryable_before_deadline() {
+        assert!(is_retryable_pipe_error(Some(2)));
+        assert!(is_retryable_pipe_error(Some(3)));
+        assert!(is_retryable_pipe_error(Some(121)));
+        assert!(is_retryable_pipe_error(Some(231)));
+        assert!(!is_retryable_pipe_error(Some(5)));
+        assert!(!is_retryable_pipe_error(None));
+    }
+}