diff --git a/Cargo.toml b/Cargo.toml
index 808dc626..eabc13f1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,3 +22,5 @@ egui_web = { path = 'egui_web' }
 # opt-level = 1 # very slow and big wasm. Don't do this.
 opt-level = 2 # fast and small wasm, basically same as `opt-level = 's'`
 # opt-level = 3 # unecessarily large wasm for no performance gain
+
+# debug = true # include debug symbols, useful when profiling wasm
diff --git a/build_demo_web.sh b/build_demo_web.sh
index a40772c2..b76eeac8 100755
--- a/build_demo_web.sh
+++ b/build_demo_web.sh
@@ -30,8 +30,11 @@ wasm-bindgen "target/wasm32-unknown-unknown/$BUILD/$TARGET_NAME" \
   --out-dir docs --no-modules --no-typescript
 
 # brew install wabt # to get wasm-strip
-wasm-strip docs/${CRATE_NAME}_bg.wasm
+# wasm-strip docs/${CRATE_NAME}_bg.wasm
 
-echo "Finished: docs/${CRATE_NAME}_bg.wasm"
+echo "Optimizing wasm…"
+# brew install binaryen # to get wasm-opt
+wasm-opt docs/egui_demo_app_bg.wasm -O2 --fast-math -o docs/egui_demo_app_bg.wasm # add -g to get debug symbols
+echo "Finished docs/${CRATE_NAME}_bg.wasm"
 
 open http://localhost:8888/index.html