diff --git a/.gitmodules b/.gitmodules
index 111d41b..07d0dd5 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "submodules/cpp-httplib"]
 	path = submodules/cpp-httplib
 	url = https://github.com/yhirose/cpp-httplib
+[submodule "submodules/qssb.h"]
+	path = submodules/qssb.h
+	url = https://git.quitesimple.org/qssb.h
diff --git a/submodules/qssb.h b/submodules/qssb.h
new file mode 160000
index 0000000..60776be
--- /dev/null
+++ b/submodules/qssb.h
@@ -0,0 +1 @@
+Subproject commit 60776be4160fe7e2178b3790cd43a76d412843b6