diff --git a/dist/py/codemp.pyi b/dist/py/codemp.pyi
index 5a92bbc..528f37f 100644
--- a/dist/py/codemp.pyi
+++ b/dist/py/codemp.pyi
@@ -8,7 +8,7 @@ class Driver:
 	def stop(self) -> None: ...
 
 
-def init(logger_cb: Callable, debug: bool) -> Driver: ...
+def init(logger_cb: Callable[[str], None], debug: bool) -> Driver: ...
 
 class Promise[T]:
 	"""
@@ -19,8 +19,8 @@ class Promise[T]:
 
 	It can either be used directly or you can wrap it inside a future python side.
 	"""
-	def wait(self) -> T: ...
-	def is_done(self) -> bool: ...
+	def wait(self) 		-> T: ...
+	def is_done(self) 	-> bool: ...
 
 class TextChange:
 	"""
@@ -31,10 +31,10 @@ class TextChange:
 	end: int
 	content: str
 
-	def is_delete(self) -> bool: ...
-	def is_insert(self) -> bool: ...
-	def is_empty(self) -> bool: ...
-	def apply(self, txt: str) -> str: ...
+	def is_delete(self) 		-> bool: ...
+	def is_insert(self) 		-> bool: ...
+	def is_empty(self) 			-> bool: ...
+	def apply(self, txt: str) 	-> str: ...
 
 
 class BufferController:
@@ -42,15 +42,18 @@ class BufferController:
 	Handle to the controller for a specific buffer, which manages the back and forth
 	of operations to and from other peers.
 	"""
-	def content(self) -> Promise[str]: ...
+	def content(self) 							-> Promise[str]: ...
 	def send(self,
 		start: int,
 		end: int,
-		txt: str) -> Promise[None]: ...
-	def try_recv(self) -> Optional[TextChange]: ...
-	def recv(self) -> Promise[TextChange]: ...
-	def poll(self) -> Promise[None]: ...
-	def stop(self) -> bool: ...
+		txt: str) 								-> Promise[None]: ...
+	def try_recv(self) 							-> Optional[TextChange]: ...
+	def recv(self) 								-> Promise[TextChange]: ...
+	def poll(self) 								-> Promise[None]: ...
+	def callback(self,
+		cb: Callable[[BufferController], None]) -> None: ...
+	def clear_callback(self) 					-> None: ...
+	def stop(self) 								-> bool: ...
 
 
 
@@ -72,11 +75,14 @@ class CursorController:
 	def send(self,
 		path: str,
 		start: Tuple[int, int],
-		end: Tuple[int, int]) -> Promise[None]: ...
-	def try_recv(self) -> Optional[Cursor]: ...
-	def recv(self) -> Promise[Cursor]: ...
-	def poll(self) -> Promise[None]: ...
-	def stop(self) -> bool: ...
+		end: Tuple[int, int]) 					-> Promise[None]: ...
+	def try_recv(self) 							-> Optional[Cursor]: ...
+	def recv(self) 								-> Promise[Cursor]: ...
+	def poll(self) 								-> Promise[None]: ...
+	def callback(self,
+		cb: Callable[[CursorController], None]) -> None: ...
+	def clear_callback(self) 					-> None: ...
+	def stop(self) 								-> bool: ...
 
 
 class Workspace:
@@ -84,18 +90,18 @@ class Workspace:
 	Handle to a workspace inside codemp. It manages buffers.
 	A cursor is tied to the single workspace.
 	"""
-	def create(self, path: str) -> Promise[None]: ...
-	def attach(self, path: str) -> Promise[BufferController]: ...
-	def detach(self, path: str) -> bool: ...
-	def fetch_buffers(self) -> Promise[None]: ...
-	def fetch_users(self) -> Promise[None]: ...
-	def list_buffer_users(self, path: str) -> Promise[list[str]]: ...
-	def delete(self, path: str) -> Promise[None]: ...
-	def id(self) -> str: ...
-	def cursor(self) -> CursorController: ...
-	def buffer_by_name(self, path: str) -> Optional[BufferController]: ...
-	def buffer_list(self) -> list[str]: ...
-	def filetree(self, filter: Optional[str]) -> list[str]: ...
+	def create(self, path: str) 				-> Promise[None]: ...
+	def attach(self, path: str) 				-> Promise[BufferController]: ...
+	def detach(self, path: str) 				-> bool: ...
+	def fetch_buffers(self) 					-> Promise[None]: ...
+	def fetch_users(self) 						-> Promise[None]: ...
+	def list_buffer_users(self, path: str) 		-> Promise[list[str]]: ...
+	def delete(self, path: str) 				-> Promise[None]: ...
+	def id(self) 								-> str: ...
+	def cursor(self) 							-> CursorController: ...
+	def buffer_by_name(self, path: str) 		-> Optional[BufferController]: ...
+	def buffer_list(self) 						-> list[str]: ...
+	def filetree(self, filter: Optional[str]) 	-> list[str]: ...
 
 
 class Client:
@@ -103,9 +109,11 @@ class Client:
 	Handle to the actual client that manages the session. It manages the connection
 	to a server and joining/creating new workspaces
 	"""
-	def __new__(cls, host: str, username: str, password: str) -> None: ...
-	def join_workspace(self, workspace: str) -> Promise[Workspace]: ...
-	def leave_workspace(self, workspace: str) -> bool: ...
-	def get_workspace(self, id: str) -> Workspace: ...
-	def active_workspaces(self) -> list[str]: ...
-	def user_id(self) -> str: ...
+	def __new__(cls,
+		host: str,
+		username: str, password: str) 			-> Client: ...
+	def join_workspace(self, workspace: str) 	-> Promise[Workspace]: ...
+	def leave_workspace(self, workspace: str) 	-> bool: ...
+	def get_workspace(self, id: str) 			-> Workspace: ...
+	def active_workspaces(self) 				-> list[str]: ...
+	def user_id(self) 							-> str: ...
diff --git a/src/ffi/python/controllers.rs b/src/ffi/python/controllers.rs
index d599ca7..f68f14f 100644
--- a/src/ffi/python/controllers.rs
+++ b/src/ffi/python/controllers.rs
@@ -4,6 +4,7 @@ use crate::api::TextChange;
 use crate::buffer::Controller as BufferController;
 use crate::cursor::Controller as CursorController;
 use pyo3::prelude::*;
+use pyo3::types::PyFunction;
 
 use super::Promise;
 use crate::a_sync_allow_threads;
@@ -48,6 +49,23 @@ impl CursorController {
 		a_sync_allow_threads!(py, this.poll().await)
 	}
 
+	#[pyo3(name = "callback")]
+	fn pycallback(&self, py: Python, cb: Py<PyFunction>) {
+		py.allow_threads(move || {
+			self.callback(move |ctl| {
+				Python::with_gil(|py| {
+					// TODO what to do with this error?
+					let _ = cb.call1(py, (ctl,));
+				})
+			})
+		})
+	}
+
+	#[pyo3(name = "clear_callback")]
+	fn pyclear_callback(&self) {
+		self.clear_callback();
+	}
+
 	#[pyo3(name = "stop")]
 	fn pystop(&self) -> bool {
 		self.stop()
@@ -94,6 +112,23 @@ impl BufferController {
 		a_sync_allow_threads!(py, this.poll().await)
 	}
 
+	#[pyo3(name = "callback")]
+	fn pycallback(&self, py: Python, cb: Py<PyFunction>) {
+		py.allow_threads(move || {
+			self.callback(move |ctl| {
+				Python::with_gil(|py| {
+					// TODO what to do with this error?
+					let _ = cb.call1(py, (ctl,));
+				})
+			})
+		})
+	}
+
+	#[pyo3(name = "clear_callback")]
+	fn pyclear_callback(&self) {
+		self.clear_callback();
+	}
+
 	#[pyo3(name = "stop")]
 	fn pystop(&self) -> bool {
 		self.stop()