diff --git a/.gitignore b/.gitignore
index 9ef1177..db191e5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -66,3 +66,4 @@ Makefile.in
 /src/matrix-enums.c
 /src/matrix-http-api.c
 /src/matrix-http-client.c
+/src/matrix-compacts.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 3273a95..52ee23a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,6 +21,7 @@ libmatrix_glib_0_0_la_VALA_SOURCES = \
 	matrix-enums.vala \
 	matrix-http-api.vala \
 	matrix-http-client.vala \
+	matrix-compacts.vala \
 	$(NULL)
 
 AM_CPPFLAGS += \
diff --git a/src/matrix-compacts.vala b/src/matrix-compacts.vala
new file mode 100644
index 0000000..bf4d318
--- /dev/null
+++ b/src/matrix-compacts.vala
@@ -0,0 +1,38 @@
+/*
+ * This file is part of matrix-glib-sdk
+ *
+ * matrix-glib-sdk is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * matrix-glib-sdk is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with matrix-glib-sdk. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+namespace Matrix {
+    /**
+     * Abstract parent class for classes that can be saved to JSON.
+     */
+    public abstract class JsonCompact {
+        public abstract Json.Node?
+        get_json_node()
+            throws Matrix.Error;
+
+        public string
+        get_json_data(out size_t datalen)
+            throws Matrix.Error
+        {
+            var generator = new Json.Generator();
+
+            generator.set_root(get_json_node());
+
+            return generator.to_data(out datalen);
+        }
+    }
+}