diff --git a/Cargo.toml b/Cargo.toml
index bb42113..9369aee 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,3 +29,4 @@ tonic-build = "0.9"
 default = ["proto", "global"]
 proto   = ["dep:prost"]
 global  = ["dep:lazy_static"]
+sync    = []
diff --git a/src/client.rs b/src/client.rs
index 903833d..60c911b 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -42,6 +42,7 @@ impl Client {
 	}
 
 	pub fn leave_workspace(&mut self) {
+		// TODO need to stop tasks?
 		self.workspace = None
 	}
 
diff --git a/src/instance.rs b/src/instance.rs
index b7772be..fd5b481 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -1,75 +1,171 @@
-use std::sync::{Arc, Mutex};
-
-use tokio::runtime::Runtime;
-
-use crate::{
-	buffer::controller::BufferController,
-	errors::Error, client::Client, cursor::controller::CursorController,
-};
-
 #[cfg(feature = "global")]
 pub mod global {
+	#[cfg(not(feature = "sync"))]
 	lazy_static::lazy_static! {
-		pub static ref INSTANCE : super::Instance = super::Instance::default();
+		pub static ref INSTANCE : super::a_sync::Instance = super::a_sync::Instance::default();
+	}
+
+	#[cfg(feature = "sync")]
+	lazy_static::lazy_static! {
+		pub static ref INSTANCE : super::sync::Instance = super::sync::Instance::default();
 	}
 }
 
-pub struct Instance {
-	client: Mutex<Option<Client>>,
-	runtime: Runtime,
-}
+#[cfg(not(feature = "sync"))]
+pub mod a_sync {
+	use std::sync::Arc;
+	
+	use tokio::sync::Mutex;
+	
+	use crate::{
+		buffer::controller::BufferController,
+		errors::Error, client::Client, cursor::controller::CursorController,
+	};
 
-impl Default for Instance {
-	fn default() -> Self {
-		Instance {
-			client: Mutex::new(None),
-			runtime: Runtime::new().expect("could not start tokio runtime"),
+	#[derive(Default)]
+	pub struct Instance {
+		client: Mutex<Option<Client>>,
+	}
+	
+	impl Instance {
+		pub async fn connect(&self, addr: &str) -> Result<(), Error> {
+			*self.client.lock().await = Some(Client::new(addr).await?);
+			Ok(())
+		}
+	
+		pub async fn join(&self, session: &str) -> Result<Arc<CursorController>, Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.join(session)
+				.await
+		}
+	
+		pub async fn create(&self, path: &str, content: Option<&str>) -> Result<(), Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.create(path, content)
+				.await
+		}
+	
+		pub async fn attach(&self, path: &str) -> Result<Arc<BufferController>, Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.attach(path)
+				.await
+		}
+	
+		pub async fn get_cursor(&self) -> Result<Arc<CursorController>, Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.get_cursor()
+				.ok_or(Error::InvalidState { msg: "join workspace first".into() })
+		}
+	
+		pub async fn get_buffer(&self, path: &str) -> Result<Arc<BufferController>, Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.get_buffer(path)
+				.ok_or(Error::InvalidState { msg: "join workspace first".into() })
+		}
+	
+		pub async fn leave_workspace(&self) -> Result<(), Error> {
+			self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.leave_workspace();
+			Ok(())
+		}
+	
+		pub async fn disconnect_buffer(&self, path: &str) -> Result<bool, Error> {
+			let res = self.client
+				.lock().await
+				.as_mut()
+				.ok_or(Error::InvalidState { msg: "connect first".into() })?
+				.disconnect_buffer(path);
+			Ok(res)
 		}
 	}
 }
 
-impl Instance {
+#[cfg(feature = "sync")]
+pub mod sync {
+	use std::sync::{Mutex, Arc};
 
-	fn if_client<T>(&self, op: impl FnOnce(&mut Client) -> T) -> Result<T, Error> {
-		if let Some(c) = self.client.lock().expect("client mutex poisoned").as_mut() {
-			Ok(op(c))
-		} else {
-			Err(Error::InvalidState { msg: "connect first".into() })
+	use tokio::runtime::Runtime;
+
+	use crate::{
+		client::Client, Error,
+		cursor::controller::CursorController,
+		buffer::controller::BufferController
+	};
+
+	pub struct Instance {
+		client: Mutex<Option<Client>>,
+		runtime: Runtime,
+	}
+	
+	impl Default for Instance {
+		fn default() -> Self {
+			Instance {
+				client: Mutex::new(None),
+				runtime: Runtime::new().expect("could not start tokio runtime"),
+			}
 		}
 	}
-
-	pub fn rt(&self) -> &Runtime { &self.runtime }
-
-	pub fn connect(&self, addr: &str) -> Result<(), Error> {
-		*self.client.lock().expect("client mutex poisoned") = Some(self.rt().block_on(Client::new(addr))?);
-		Ok(())
-	}
-
-	pub fn join(&self, session: &str) -> Result<Arc<CursorController>, Error> {
-		self.if_client(|c| self.rt().block_on(c.join(session)))?
-	}
-
-	pub fn create(&self, path: &str, content: Option<&str>) -> Result<(), Error> {
-		self.if_client(|c| self.rt().block_on(c.create(path, content)))?
-	}
-
-	pub fn attach(&self, path: &str) -> Result<Arc<BufferController>, Error> {
-		self.if_client(|c| self.rt().block_on(c.attach(path)))?
-	}
-
-	pub fn get_cursor(&self) -> Result<Arc<CursorController>, Error> {
-		self.if_client(|c| c.get_cursor().ok_or(Error::InvalidState { msg: "join workspace first".into() }))?
-	}
-
-	pub fn get_buffer(&self, path: &str) -> Result<Arc<BufferController>, Error> {
-		self.if_client(|c| c.get_buffer(path).ok_or(Error::InvalidState { msg: "join workspace or create requested buffer first".into() }))?
-	}
-
-	pub fn leave_workspace(&self) -> Result<(), Error> {
-		self.if_client(|c| c.leave_workspace())
-	}
-
-	pub fn disconnect_buffer(&self, path: &str) -> Result<bool, Error> {
-		self.if_client(|c| c.disconnect_buffer(path))
+	
+	impl Instance {
+		fn if_client<T>(&self, op: impl FnOnce(&mut Client) -> T) -> Result<T, Error> {
+			if let Some(c) = self.client.lock().expect("client mutex poisoned").as_mut() {
+				Ok(op(c))
+			} else {
+				Err(Error::InvalidState { msg: "connect first".into() })
+			}
+		}
+	
+		pub fn rt(&self) -> &Runtime { &self.runtime }
+	
+		pub fn connect(&self, addr: &str) -> Result<(), Error> {
+			*self.client.lock().expect("client mutex poisoned") = Some(self.rt().block_on(Client::new(addr))?);
+			Ok(())
+		}
+	
+		pub fn join(&self, session: &str) -> Result<Arc<CursorController>, Error> {
+			self.if_client(|c| self.rt().block_on(c.join(session)))?
+		}
+	
+		pub fn create(&self, path: &str, content: Option<&str>) -> Result<(), Error> {
+			self.if_client(|c| self.rt().block_on(c.create(path, content)))?
+		}
+	
+		pub fn attach(&self, path: &str) -> Result<Arc<BufferController>, Error> {
+			self.if_client(|c| self.rt().block_on(c.attach(path)))?
+		}
+	
+		pub fn get_cursor(&self) -> Result<Arc<CursorController>, Error> {
+			self.if_client(|c| c.get_cursor().ok_or(Error::InvalidState { msg: "join workspace first".into() }))?
+		}
+	
+		pub fn get_buffer(&self, path: &str) -> Result<Arc<BufferController>, Error> {
+			self.if_client(|c| c.get_buffer(path).ok_or(Error::InvalidState { msg: "join workspace or create requested buffer first".into() }))?
+		}
+	
+		pub fn leave_workspace(&self) -> Result<(), Error> {
+			self.if_client(|c| c.leave_workspace())
+		}
+	
+		pub fn disconnect_buffer(&self, path: &str) -> Result<bool, Error> {
+			self.if_client(|c| c.disconnect_buffer(path))
+		}
 	}
 }