diff --git a/src/external-api-docs/doxygen.cfg.in b/src/external-api-docs/doxygen.cfg.in
index 1be71d895e2..7ae4c83dfb8 100644
--- a/src/external-api-docs/doxygen.cfg.in
+++ b/src/external-api-docs/doxygen.cfg.in
@@ -56,3 +56,5 @@ GENERATE_TREEVIEW = YES
 OPTIMIZE_OUTPUT_FOR_C  = YES
 
 USE_MDFILE_AS_MAINPAGE = doc/external-api/README.md
+
+QUIET = YES
diff --git a/src/internal-api-docs/doxygen.cfg.in b/src/internal-api-docs/doxygen.cfg.in
index 86c64a3961d..bf4c42d11c7 100644
--- a/src/internal-api-docs/doxygen.cfg.in
+++ b/src/internal-api-docs/doxygen.cfg.in
@@ -97,3 +97,6 @@ EXPAND_AS_DEFINED      = \
   DECLARE_WORKER_SERIALISER \
   DECLARE_SERVE_SERIALISER \
   LENGTH_PREFIXED_PROTO_HELPER
+
+WARN_IF_UNDOCUMENTED = NO
+QUIET = YES