diff --git a/requirements.txt b/requirements.txt
index 5b0e2a3..cd00860 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,8 +7,8 @@ cryptography>=41.0.0
 # Optional: HTTP/2 multiplexing (faster apps_script relay)
 h2>=4.1.0
 
-# Optional: CA bundle for TLS verification (recommended on macOS / Windows)
-certifi>=2024.1.0
+# CA bundle for TLS verification — skipped on Windows (uses system cert store).
+certifi>=2024.1.0; sys_platform != "win32"
 
 # Optional: Brotli decompression (modern websites send `br` encoding)
 brotli>=1.1.0