diff --git a/mm2src/mm2_net/Cargo.toml b/mm2src/mm2_net/Cargo.toml
index fd42e034ac..5627f003ff 100644
--- a/mm2src/mm2_net/Cargo.toml
+++ b/mm2src/mm2_net/Cargo.toml
@@ -49,7 +49,7 @@ wasm-bindgen-futures = "0.4.21"
 web-sys = { version = "0.3.55", features = ["console", "CloseEvent", "DomException", "ErrorEvent", "IdbDatabase",
     "IdbCursor", "IdbCursorWithValue", "IdbFactory", "IdbIndex", "IdbIndexParameters", "IdbObjectStore",
     "IdbObjectStoreParameters", "IdbOpenDbRequest", "IdbKeyRange", "IdbTransaction", "IdbTransactionMode",
-    "IdbVersionChangeEvent", "MessageEvent", "MessagePort", "ReadableStreamDefaultReader", "ReadableStream", "SharedWorker", "WebSocket"] }
+    "IdbVersionChangeEvent", "MessageEvent", "MessagePort", "ReadableStreamDefaultReader", "ReadableStream", "SharedWorker", "Url", "WebSocket"] }
 
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
diff --git a/mm2src/mm2_net/src/wasm/wasm_ws.rs b/mm2src/mm2_net/src/wasm/wasm_ws.rs
index 661babef3c..a0a7bbb067 100644
--- a/mm2src/mm2_net/src/wasm/wasm_ws.rs
+++ b/mm2src/mm2_net/src/wasm/wasm_ws.rs
@@ -16,7 +16,7 @@ use std::sync::Arc;
 use std::task::{Context, Poll};
 use wasm_bindgen::prelude::*;
 use wasm_bindgen::JsCast;
-use web_sys::{CloseEvent, DomException, MessageEvent, WebSocket};
+use web_sys::{CloseEvent, DomException, MessageEvent, Url, WebSocket};
 
 const NORMAL_CLOSURE_CODE: u16 = 1000;
 
@@ -50,8 +50,17 @@ pub enum InitWsError {
 impl InitWsError {
     fn from_ws_new_err(e: JsValue, url: &str) -> InitWsError {
         let reason = stringify_js_error(&e);
-        match e.dyn_ref::<DomException>().map(DomException::code) {
-            Some(DomException::SYNTAX_ERR) => InitWsError::InvalidUrl {
+
+        // Check for TypeError
+        if reason.contains("URL constructor") {
+            return InitWsError::InvalidUrl {
+                url: url.to_owned(),
+                reason,
+            };
+        };
+
+        match e.dyn_ref::<DomException>().map(DomException::name) {
+            Some(ref name) if name == "SyntaxError" => InitWsError::InvalidUrl {
                 url: url.to_owned(),
                 reason,
             },
@@ -312,6 +321,7 @@ struct WebSocketImpl {
 
 impl WebSocketImpl {
     fn init(url: &str) -> InitWsResult<(WebSocketImpl, WsTransportReceiver)> {
+        Self::validate_websocket_url(url)?;
         let ws = WebSocket::new(url).map_to_mm(|e| InitWsError::from_ws_new_err(e, url))?;
 
         let (tx, rx) = mpsc::channel(1024);
@@ -355,6 +365,20 @@ impl WebSocketImpl {
             },
         }
     }
+
+    fn validate_websocket_url(url: &str) -> Result<(), MmError<InitWsError>> {
+        let parsed_url = Url::new(url).map_to_mm(|e| InitWsError::from_ws_new_err(e, url))?;
+
+        let scheme = parsed_url.protocol();
+        if scheme != "ws:" && scheme != "wss:" {
+            return MmError::err(InitWsError::InvalidUrl {
+                url: url.to_string(),
+                reason: "URL must use 'ws' or 'wss' scheme".to_string(),
+            });
+        }
+
+        Ok(())
+    }
 }
 
 impl Drop for WebSocketImpl {