diff --git a/src/wasm-lib/Cargo.lock b/src/wasm-lib/Cargo.lock
index 9e6b6f235..e69eac223 100644
--- a/src/wasm-lib/Cargo.lock
+++ b/src/wasm-lib/Cargo.lock
@@ -1426,7 +1426,7 @@ dependencies = [
 
 [[package]]
 name = "kcl-lib"
-version = "0.1.39"
+version = "0.1.40"
 dependencies = [
  "anyhow",
  "async-recursion",
diff --git a/src/wasm-lib/kcl/Cargo.toml b/src/wasm-lib/kcl/Cargo.toml
index d95d7bafc..69b852507 100644
--- a/src/wasm-lib/kcl/Cargo.toml
+++ b/src/wasm-lib/kcl/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "kcl-lib"
 description = "KittyCAD Language implementation and tools"
-version = "0.1.39"
+version = "0.1.40"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/KittyCAD/modeling-app"
diff --git a/src/wasm-lib/kcl/src/engine/conn.rs b/src/wasm-lib/kcl/src/engine/conn.rs
index 356211a6f..0ff96c0e6 100644
--- a/src/wasm-lib/kcl/src/engine/conn.rs
+++ b/src/wasm-lib/kcl/src/engine/conn.rs
@@ -69,7 +69,16 @@ impl EngineConnection {
     async fn start_write_actor(mut tcp_write: WebSocketTcpWrite, mut engine_req_rx: mpsc::Receiver<ToEngineReq>) {
         while let Some(req) = engine_req_rx.recv().await {
             let ToEngineReq { req, request_sent } = req;
-            let res = Self::inner_send_to_engine(req, &mut tcp_write).await;
+            let res = if let kittycad::types::WebSocketRequest::ModelingCmdReq { cmd, cmd_id: _ } = &req {
+                if let kittycad::types::ModelingCmd::ImportFiles { .. } = cmd {
+                    // Send it as binary.
+                    Self::inner_send_to_engine_binary(req, &mut tcp_write).await
+                } else {
+                    Self::inner_send_to_engine(req, &mut tcp_write).await
+                }
+            } else {
+                Self::inner_send_to_engine(req, &mut tcp_write).await
+            };
             let _ = request_sent.send(res);
         }
     }
@@ -84,6 +93,16 @@ impl EngineConnection {
         Ok(())
     }
 
+    /// Send the given `request` to the engine via the WebSocket connection `tcp_write` as binary.
+    async fn inner_send_to_engine_binary(request: WebSocketRequest, tcp_write: &mut WebSocketTcpWrite) -> Result<()> {
+        let msg = bson::to_vec(&request).map_err(|e| anyhow!("could not serialize bson: {e}"))?;
+        tcp_write
+            .send(WsMsg::Binary(msg))
+            .await
+            .map_err(|e| anyhow!("could not send json over websocket: {e}"))?;
+        Ok(())
+    }
+
     pub async fn new(ws: reqwest::Upgraded) -> Result<EngineConnection> {
         let ws_stream = tokio_tungstenite::WebSocketStream::from_raw_socket(
             ws,