diff --git a/src/bayou.rs b/src/bayou.rs
index afe3c75..3c525b3 100644
--- a/src/bayou.rs
+++ b/src/bayou.rs
@@ -58,12 +58,12 @@ pub struct Bayou<S: BayouState> {
 }
 
 impl<S: BayouState> Bayou<S> {
-    pub fn new(creds: &Credentials, path: String) -> Result<Self> {
-        let storage = creds.storage.build()?;
+    pub async fn new(creds: &Credentials, path: String) -> Result<Self> {
+        let storage = creds.storage.build().await?;
 
         //let target = k2v_client.row(&path, WATCH_SK);
         let target = storage::RowRef::new(&path, WATCH_SK);
-        let watch = K2vWatch::new(creds, target.clone())?;
+        let watch = K2vWatch::new(creds, target.clone()).await?;
 
         Ok(Self {
             path,
@@ -418,8 +418,8 @@ impl K2vWatch {
     /// Creates a new watch and launches subordinate threads.
     /// These threads hold Weak pointers to the struct;
     /// they exit when the Arc is dropped.
-    fn new(creds: &Credentials, target: storage::RowRef) -> Result<Arc<Self>> {
-        let storage = creds.storage.build()?;
+    async fn new(creds: &Credentials, target: storage::RowRef) -> Result<Arc<Self>> {
+        let storage = creds.storage.build().await?;
 
         let (tx, rx) = watch::channel::<storage::RowRef>(target.clone());
         let notify = Notify::new();
diff --git a/src/mail/incoming.rs b/src/mail/incoming.rs
index 2a6c947..3eafac7 100644
--- a/src/mail/incoming.rs
+++ b/src/mail/incoming.rs
@@ -51,8 +51,8 @@ async fn incoming_mail_watch_process_internal(
     creds: Credentials,
     mut rx_inbox_id: watch::Receiver<Option<(UniqueIdent, ImapUidvalidity)>>,
 ) -> Result<()> {
-    let mut lock_held = k2v_lock_loop(creds.storage.build()?, storage::RowRef::new(INCOMING_PK, INCOMING_LOCK_SK));
-    let storage = creds.storage.build()?;
+    let mut lock_held = k2v_lock_loop(creds.storage.build().await?, storage::RowRef::new(INCOMING_PK, INCOMING_LOCK_SK));
+    let storage = creds.storage.build().await?;
 
     let mut inbox: Option<Arc<Mailbox>> = None;
     let mut incoming_key = storage::RowRef::new(INCOMING_PK, INCOMING_WATCH_SK);
@@ -411,7 +411,7 @@ impl EncryptedMessage {
     }
 
     pub async fn deliver_to(self: Arc<Self>, creds: PublicCredentials) -> Result<()> {
-        let storage = creds.storage.build()?;
+        let storage = creds.storage.build().await?;
 
         // Get causality token of previous watch key
         let query = storage::RowRef::new(INCOMING_PK, INCOMING_WATCH_SK);
diff --git a/src/mail/mailbox.rs b/src/mail/mailbox.rs
index 65f44b1..60a91dd 100644
--- a/src/mail/mailbox.rs
+++ b/src/mail/mailbox.rs
@@ -25,7 +25,7 @@ impl Mailbox {
         let index_path = format!("index/{}", id);
         let mail_path = format!("mail/{}", id);
 
-        let mut uid_index = Bayou::<UidIndex>::new(creds, index_path)?;
+        let mut uid_index = Bayou::<UidIndex>::new(creds, index_path).await?;
         uid_index.sync().await?;
 
         let uidvalidity = uid_index.state().uidvalidity;
@@ -44,7 +44,7 @@ impl Mailbox {
         let mbox = RwLock::new(MailboxInternal {
             id,
             encryption_key: creds.keys.master.clone(),
-            storage: creds.storage.build()?,
+            storage: creds.storage.build().await?,
             uid_index,
             mail_path,
         });
diff --git a/src/mail/user.rs b/src/mail/user.rs
index 8413cbf..8d12c58 100644
--- a/src/mail/user.rs
+++ b/src/mail/user.rs
@@ -174,7 +174,7 @@ impl User {
     // ---- Internal user & mailbox management ----
 
     async fn open(username: String, creds: Credentials) -> Result<Arc<Self>> {
-        let storage = creds.storage.build()?;
+        let storage = creds.storage.build().await?;
 
         let (tx_inbox_id, rx_inbox_id) = watch::channel(None);
 
diff --git a/src/storage/garage.rs b/src/storage/garage.rs
index f202067..5d00ed6 100644
--- a/src/storage/garage.rs
+++ b/src/storage/garage.rs
@@ -1,5 +1,6 @@
 use crate::storage::*;
 use serde::Serialize;
+use aws_sdk_s3 as s3;
 
 #[derive(Clone, Debug, Serialize)]
 pub struct GarageConf {
@@ -26,9 +27,26 @@ impl GarageBuilder {
     } 
 }
 
+#[async_trait]
 impl IBuilder for GarageBuilder {
-    fn build(&self) -> Result<Store, StorageError> {
-        unimplemented!();
+    async fn build(&self) -> Result<Store, StorageError> {
+        let creds = s3::config::Credentials::new(
+            self.conf.aws_access_key_id.clone(), 
+            self.conf.aws_secret_access_key.clone(), 
+            None, 
+            None, 
+            "aerogramme"
+        );
+
+        let config = aws_config::from_env()
+            .region(aws_config::Region::new(self.conf.region.clone()))
+            .credentials_provider(creds)
+            .endpoint_url(self.conf.s3_endpoint.clone())
+            .load()
+            .await;
+
+        let s3_client = aws_sdk_s3::Client::new(&config);
+        Ok(Box::new(GarageStore { s3: s3_client }))
     }
     fn unique(&self) -> UnicityBuffer {
         UnicityBuffer(self.unicity.clone())
@@ -36,7 +54,7 @@ impl IBuilder for GarageBuilder {
 }
 
 pub struct GarageStore {
-    dummy: String,
+    s3: s3::Client,
 }
 
 #[async_trait]
diff --git a/src/storage/in_memory.rs b/src/storage/in_memory.rs
index fb6e599..723bca0 100644
--- a/src/storage/in_memory.rs
+++ b/src/storage/in_memory.rs
@@ -106,8 +106,9 @@ impl MemBuilder {
     }
 }
 
+#[async_trait]
 impl IBuilder for MemBuilder {
-    fn build(&self) -> Result<Store, StorageError> {
+    async fn build(&self) -> Result<Store, StorageError> {
         Ok(Box::new(MemStore {
             row: self.row.clone(),
             blob: self.blob.clone(),
diff --git a/src/storage/mod.rs b/src/storage/mod.rs
index 0fedfab..10149e9 100644
--- a/src/storage/mod.rs
+++ b/src/storage/mod.rs
@@ -157,8 +157,9 @@ pub trait IStore {
 #[derive(Clone,Debug,PartialEq,Eq,Hash)]
 pub struct UnicityBuffer(Vec<u8>);
 
+#[async_trait]
 pub trait IBuilder: std::fmt::Debug {
-    fn build(&self) -> Result<Store, StorageError>;
+    async fn build(&self) -> Result<Store, StorageError>;
 
     /// Returns an opaque buffer that uniquely identifies this builder
     fn unique(&self) -> UnicityBuffer;