diff --git a/mongoose.c b/mongoose.c
index f38d37b9..17d64f86 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -16603,9 +16603,9 @@ size_t mg_ws_send(struct mg_connection *c, const void *buf, size_t len,
                   int op) {
   uint8_t header[14];
   size_t header_len = mkhdr(len, op, c->is_client, header);
-  mg_send(c, header, header_len);
+  if (!mg_send(c, header, header_len)) return 0;
+  if (!mg_send(c, buf, len)) return header_len;
   MG_VERBOSE(("WS out: %d [%.*s]", (int) len, (int) len, buf));
-  mg_send(c, buf, len);
   mg_ws_mask(c, len);
   return header_len + len;
 }
@@ -16757,12 +16757,12 @@ size_t mg_ws_wrap(struct mg_connection *c, size_t len, int op) {
   size_t header_len = mkhdr(len, op, c->is_client, header);
 
   // NOTE: order of operations is important!
-  mg_iobuf_add(&c->send, c->send.len, NULL, header_len);
-  p = &c->send.buf[c->send.len - len];         // p points to data
-  memmove(p, p - header_len, len);             // Shift data
-  memcpy(p - header_len, header, header_len);  // Prepend header
-  mg_ws_mask(c, len);                          // Mask data
-
+  if (mg_iobuf_add(&c->send, c->send.len, NULL, header_len) != 0) {
+    p = &c->send.buf[c->send.len - len];         // p points to data
+    memmove(p, p - header_len, len);             // Shift data
+    memcpy(p - header_len, header, header_len);  // Prepend header
+    mg_ws_mask(c, len);                          // Mask data
+  }
   return c->send.len;
 }
 
diff --git a/src/ws.c b/src/ws.c
index a3ed5c82..e3bc0281 100644
--- a/src/ws.c
+++ b/src/ws.c
@@ -133,9 +133,9 @@ size_t mg_ws_send(struct mg_connection *c, const void *buf, size_t len,
                   int op) {
   uint8_t header[14];
   size_t header_len = mkhdr(len, op, c->is_client, header);
-  mg_send(c, header, header_len);
+  if (!mg_send(c, header, header_len)) return 0;
+  if (!mg_send(c, buf, len)) return header_len;
   MG_VERBOSE(("WS out: %d [%.*s]", (int) len, (int) len, buf));
-  mg_send(c, buf, len);
   mg_ws_mask(c, len);
   return header_len + len;
 }
@@ -287,11 +287,11 @@ size_t mg_ws_wrap(struct mg_connection *c, size_t len, int op) {
   size_t header_len = mkhdr(len, op, c->is_client, header);
 
   // NOTE: order of operations is important!
-  mg_iobuf_add(&c->send, c->send.len, NULL, header_len);
-  p = &c->send.buf[c->send.len - len];         // p points to data
-  memmove(p, p - header_len, len);             // Shift data
-  memcpy(p - header_len, header, header_len);  // Prepend header
-  mg_ws_mask(c, len);                          // Mask data
-
+  if (mg_iobuf_add(&c->send, c->send.len, NULL, header_len) != 0) {
+    p = &c->send.buf[c->send.len - len];         // p points to data
+    memmove(p, p - header_len, len);             // Shift data
+    memcpy(p - header_len, header, header_len);  // Prepend header
+    mg_ws_mask(c, len);                          // Mask data
+  }
   return c->send.len;
 }