diff --git a/include/sway/container.h b/include/sway/container.h
index 215c0b07..67b747a0 100644
--- a/include/sway/container.h
+++ b/include/sway/container.h
@@ -2,6 +2,7 @@
 #define _SWAY_CONTAINER_H
 #include <sys/types.h>
 #include <wlc/wlc.h>
+#include <stdint.h>
 
 #include "list.h"
 
@@ -58,6 +59,12 @@ struct sway_container {
 	 */
 	wlc_handle handle;
 
+	/**
+	 * A unique ID to identify this container. Primarily used in the
+	 * get_tree JSON output.
+	 */
+	size_t id;
+
 	enum swayc_types type;
 	enum swayc_layouts layout;
 	enum swayc_layouts prev_layout;
diff --git a/sway/container.c b/sway/container.c
index 561dcba6..73b627ec 100644
--- a/sway/container.c
+++ b/sway/container.c
@@ -18,8 +18,12 @@
 #define ASSERT_NONNULL(PTR) \
 	sway_assert (PTR, #PTR "must be non-null")
 
+
 static swayc_t *new_swayc(enum swayc_types type) {
+	// next id starts at 1 because 0 is assigned to root_container in layout.c
+	static size_t next_id = 1;
 	swayc_t *c = calloc(1, sizeof(swayc_t));
+	c->id = next_id++;
 	c->handle = -1;
 	c->gaps = -1;
 	c->layout = L_NONE;
diff --git a/sway/ipc-json.c b/sway/ipc-json.c
index 1ca7f9ce..e08b3c60 100644
--- a/sway/ipc-json.c
+++ b/sway/ipc-json.c
@@ -161,7 +161,6 @@ static void ipc_json_describe_view(swayc_t *c, json_object *object) {
 		ipc_json_layout_description(c->parent->prev_layout) : "none";
 	wlc_handle parent = wlc_view_get_parent(c->handle);
 
-	json_object_object_add(object, "id", json_object_new_int(c->handle));
 	json_object_object_add(object, "type", json_object_new_string((c->is_floating) ? "floating_con" : "con"));
 
 	json_object_object_add(object, "scratchpad_state",
@@ -211,7 +210,7 @@ json_object *ipc_json_describe_container(swayc_t *c) {
 
 	json_object *object = json_object_new_object();
 
-	json_object_object_add(object, "id", json_object_new_int((uintptr_t)&c));
+	json_object_object_add(object, "id", json_object_new_int((int)c->id));
 	json_object_object_add(object, "name", (c->name) ? json_object_new_string(c->name) : NULL);
 	json_object_object_add(object, "rect", ipc_json_create_rect(c));
 	json_object_object_add(object, "visible", json_object_new_boolean(c->visible));
diff --git a/sway/layout.c b/sway/layout.c
index 7802c412..6012af66 100644
--- a/sway/layout.c
+++ b/sway/layout.c
@@ -22,6 +22,7 @@ int min_sane_h = 60;
 int min_sane_w = 100;
 
 void init_layout(void) {
+	root_container.id = 0; // normally assigned in new_swayc()
 	root_container.type = C_ROOT;
 	root_container.layout = L_NONE;
 	root_container.name = strdup("root");