diff --git a/include/villas/web.h b/include/villas/web.h
index fb0645b87..06aa0c12d 100644
--- a/include/villas/web.h
+++ b/include/villas/web.h
@@ -26,6 +26,7 @@
 #include <pthread.h>
 
 #include <villas/common.h>
+#include <villas/queue.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -42,6 +43,8 @@ struct web {
 	struct lws_context *context;	/**< The libwebsockets server context. */
 	struct lws_vhost *vhost;	/**< The libwebsockets vhost. */
 
+	struct queue writables;		/**< Queue of WSIs for which we will call lws_callback_on_writable() */
+
 	int port;			/**< Port of the build in HTTP / WebSocket server. */
 	char *htdocs;			/**< The root directory for files served via HTTP. */
 	char *ssl_cert;			/**< Path to the SSL certitifcate for HTTPS / WSS. */
@@ -65,6 +68,8 @@ int web_stop(struct web *w);
 /** Parse HTTPd and WebSocket related options */
 int web_parse(struct web *w, json_t *cfg);
 
+void web_callback_on_writable(struct lws *wsi);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/api.c b/lib/api.c
index 8f836dc17..04c6da9b9 100644
--- a/lib/api.c
+++ b/lib/api.c
@@ -326,7 +326,7 @@ int api_stop(struct api *a)
 
 		s->state = API_SESSION_STATE_SHUTDOWN;
 
-		lws_callback_on_writable(s->wsi);
+		web_callback_on_writable(s->wsi);
 	}
 
 	for (int i = 0; i < 10 && list_length(&a->sessions) > 0; i++) {
@@ -373,7 +373,7 @@ static void * api_worker(void *ctx)
 
 		queue_push(&s->response.queue, resp);
 
-		lws_callback_on_writable(s->wsi);
+		web_callback_on_writable(s->wsi);
 	}
 
 	return NULL;
diff --git a/lib/nodes/websocket.c b/lib/nodes/websocket.c
index 788218c6d..8c3034ecc 100644
--- a/lib/nodes/websocket.c
+++ b/lib/nodes/websocket.c
@@ -164,7 +164,7 @@ static int websocket_connection_write(struct websocket_connection *c, struct sam
 
 	/* Client connections which are currently conecting don't have an associate c->wsi yet */
 	if (c->wsi)
-		lws_callback_on_writable(c->wsi);
+		web_callback_on_writable(c->wsi);
 
 	return 0;
 }
diff --git a/lib/web.c b/lib/web.c
index 4194537ef..13e321da1 100644
--- a/lib/web.c
+++ b/lib/web.c
@@ -165,19 +165,34 @@ static void logger(int level, const char *msg) {
 	}
 }
 
+void web_callback_on_writable(struct lws *wsi)
+{
+	struct lws_context *ctx = lws_get_context(wsi);
+	struct web *w = lws_context_user(ctx);
+
+	queue_push(&w->writables, (void *) wsi);
+}
+
 static void * web_worker(void *ctx)
 {
+	struct lws *wsi;
 	struct web *w = ctx;
 
-	for (;;)
+	for (;;) {
 		lws_service(w->context, 100);
 
+		while (queue_available(&w->writables)) {
+			queue_pull(&w->writables, (void **) &wsi);
+			lws_callback_on_writable(wsi);
+		}
+	}
+
 	return NULL;
 }
 
 int web_init(struct web *w, struct api *a)
 {
-	int lvl = LLL_ERR | LLL_WARN | LLL_NOTICE;
+	int ret, lvl = LLL_ERR | LLL_WARN | LLL_NOTICE;
 
 	if (global_log->level >=10 && global_log->facilities & LOG_WEB)
 		lvl |= (1 << LLL_COUNT) - 1;
@@ -190,6 +205,10 @@ int web_init(struct web *w, struct api *a)
 	w->port = getuid() > 0 ? 8080 : 80; /**< @todo Use libcap to check if user can bind to ports < 1024 */
 	w->htdocs = strdup(WEB_PATH);
 
+	ret = queue_init(&w->writables, 128, &memory_heap);
+	if (ret)
+		return ret;
+
 	w->state = STATE_INITIALIZED;
 
 	return 0;
@@ -312,6 +331,8 @@ int web_stop(struct web *w)
 
 int web_destroy(struct web *w)
 {
+	int ret;
+
 	if (w->state == STATE_DESTROYED)
 		return 0;
 
@@ -328,6 +349,10 @@ int web_destroy(struct web *w)
 	if (w->htdocs)
 		free(w->htdocs);
 
+	ret = queue_destroy(&w->writables);
+	if (ret)
+		return ret;
+
 	w->state = STATE_DESTROYED;
 
 	return 0;