diff --git a/src/builder/b-sai.c b/src/builder/b-sai.c
index 5ff35c8..78a13a3 100644
--- a/src/builder/b-sai.c
+++ b/src/builder/b-sai.c
@@ -519,6 +519,18 @@ crash_handler(int signum)
 }
 #endif
 
+#if defined(WIN32)
+static int log_fd = -1;
+
+static void
+lwsl_emit_file(int level, const char *line)
+{
+	if (log_fd >= 0) {
+		write(log_fd, line, (unsigned int)strlen(line));
+	}
+}
+#endif
+
 int
 saib_app_run(int argc, const char **argv)
 {
@@ -593,16 +605,17 @@ saib_app_run(int argc, const char **argv)
 		lws_set_log_level(logs, lwsl_emit_syslog);
 	} else
 #endif
-
+	{
 #if defined(__linux__) || defined(__APPLE__)
-	signal(SIGSEGV, crash_handler);
-	signal(SIGABRT, crash_handler);
-	signal(SIGBUS, crash_handler);
-	signal(SIGILL, crash_handler);
-	signal(SIGFPE, crash_handler);
+		signal(SIGSEGV, crash_handler);
+		signal(SIGABRT, crash_handler);
+		signal(SIGBUS, crash_handler);
+		signal(SIGILL, crash_handler);
+		signal(SIGFPE, crash_handler);
 #endif
 
-	lws_set_log_level(logs, NULL);
+		lws_set_log_level(logs, NULL);
+	}
 
 #if defined(WIN32)
 	{
@@ -623,6 +636,14 @@ saib_app_run(int argc, const char **argv)
 		lws_snprintf(stg_config_dir, sizeof(stg_config_dir),
 				"%s\\sai\\builder", temp);
 
+		if (lws_cmdline_option(argc, argv, "--service")) {
+			char logpath[512];
+			lws_snprintf(logpath, sizeof(logpath), "%s\\sai-builder-service.log", stg_config_dir);
+			log_fd = open(logpath, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+			if (log_fd >= 0)
+				lws_set_log_level(logs, lwsl_emit_file);
+		}
+
 		config_dir = stg_config_dir;
 		CoTaskMemFree(wdi);
 	}
diff --git a/src/builder/b-ws-server.c b/src/builder/b-ws-server.c
index 0fbe627..d371ec3 100644
--- a/src/builder/b-ws-server.c
+++ b/src/builder/b-ws-server.c
@@ -155,51 +155,49 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 	struct sai_plat_server *spm = (struct sai_plat_server *)userobj;
 	sai_plat_t *sp = NULL;
 	sai_resource_t *reso;
-	struct lejp_ctx ctx;
-	lws_struct_args_t a;
 	sai_rebuild_t *reb;
 	sai_cancel_t *can;
 	int m;
 
 	lws_ss_validity_confirmed(spm->ss);
 
-	/*
-	 * use the schema name on the incoming JSON to decide what kind of
-	 * structure to instantiate
-	 */
+	if (flags & LWSSS_FLAG_SOM) {
+		memset(&spm->a, 0, sizeof(spm->a));
+		spm->a.map_st[0]		= lsm_schema_map_m_to_b;
+		spm->a.map_entries_st[0]	= LWS_ARRAY_SIZE(lsm_schema_map_m_to_b);
+		spm->a.ac_block_size		= 512;
 
-	memset(&a, 0, sizeof(a));
-	a.map_st[0]		= lsm_schema_map_m_to_b;
-	a.map_entries_st[0]	= LWS_ARRAY_SIZE(lsm_schema_map_m_to_b);
-	a.ac_block_size		= 512;
+		lws_struct_json_init_parse(&spm->ctx, NULL, &spm->a);
+	}
 
-//	lwsl_hexdump_warn(in, len);
+	m = lejp_parse(&spm->ctx, (uint8_t *)in, (int)len);
+	if (m == LEJP_CONTINUE)
+		return LWSSSSRET_OK;
 
-	lws_struct_json_init_parse(&ctx, NULL, &a);
-	m = lejp_parse(&ctx, (uint8_t *)in, (int)len);
 	if (m < 0) {
 		lwsl_hexdump_err(in, len);
 		lwsl_err("%s: builder rx JSON decode failed '%s'\n",
 			    __func__, lejp_error_to_string(m));
+		lwsac_free(&spm->a.ac);
 		return m;
 	}
 
-	if (!a.dest) {
-		lwsac_free(&a.ac);
+	if (!spm->a.dest) {
+		lwsac_free(&spm->a.ac);
 		return LWSSSSRET_OK;
 	}
 
-	switch (a.top_schema_index) {
+	switch (spm->a.top_schema_index) {
 
 	case SAIB_RX_TASK_ALLOCATION:
-		if (saib_consider_allocating_task(spm, &a, in, len, flags))
+		if (saib_consider_allocating_task(spm, &spm->a, in, len, flags))
 			break;
 
 		break;
 
 	case SAIB_RX_TASK_CANCEL:
 
-		can = (sai_cancel_t *)a.dest;
+		can = (sai_cancel_t *)spm->a.dest;
 
 		lwsl_notice("%s: received task cancel for %s, erase %d\n", __func__, can->task_uuid, can->erase);
 
@@ -260,7 +258,7 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 
 	case SAIB_RX_VIEWERSTATE:
 		{
-			sai_viewer_state_t *vs = (sai_viewer_state_t *)a.dest;
+			sai_viewer_state_t *vs = (sai_viewer_state_t *)spm->a.dest;
 			char any_busy = 0;
 
 		       lwsl_notice("Received viewer state update: %u viewers\n", vs->viewers);
@@ -306,7 +304,7 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 	case SAIB_RX_OPENSHELL:
 	{
 		extern int saib_shell_spawn(struct sai_plat_server *spm, const char *task_uuid);
-		sai_openshell_t *os = (sai_openshell_t *)a.dest;
+		sai_openshell_t *os = (sai_openshell_t *)spm->a.dest;
 		lwsl_notice("%s: OPENSHELL received from server for task %s\n", __func__, os->task_uuid);
 		saib_shell_spawn(spm, os->task_uuid);
 		break;
@@ -314,7 +312,7 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 
 		case SAIB_RX_PTYDATA:
 		{
-			sai_ptydata_t *pd = (sai_ptydata_t *)a.dest;
+			sai_ptydata_t *pd = (sai_ptydata_t *)spm->a.dest;
 			struct sai_shell *sh = NULL;
 
 			lws_start_foreach_dll(struct lws_dll2 *, d, builder.shell_owner.head) {
@@ -361,7 +359,7 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 		}
 
 	case SAIB_RX_RESOURCE_REPLY:
-		reso = (sai_resource_t *)a.dest;
+		reso = (sai_resource_t *)spm->a.dest;
 
 		lwsl_notice("%s: RESOURCE_REPLY: cookie %s\n",
 				__func__, reso->cookie);
@@ -370,7 +368,7 @@ saib_m_rx(void *userobj, const uint8_t *in, size_t len, int flags)
 		break;
 
 	case SAIB_RX_REBUILD:
-		reb = (sai_rebuild_t *)a.dest;
+		reb = (sai_rebuild_t *)spm->a.dest;
 
 		lwsl_notice("%s: REBUILD: %s\n", __func__, reb->builder_name);
 
diff --git a/src/common/include/private.h b/src/common/include/private.h
index 5e10bb4..a0f6346 100644
--- a/src/common/include/private.h
+++ b/src/common/include/private.h
@@ -542,6 +542,9 @@ typedef struct sai_plat_server {
 	char				last_msg_start[128];
 	uint8_t				inside_msg;
 	uint8_t				tx_corrupted;
+
+	struct lejp_ctx			ctx;
+	lws_struct_args_t		a;
 } sai_plat_server_t;
 
 struct sai_env {