diff --git a/packages/cli/src/config/web.rs b/packages/cli/src/config/web.rs
index b3dea5631..8e1343f9f 100644
--- a/packages/cli/src/config/web.rs
+++ b/packages/cli/src/config/web.rs
@@ -62,6 +62,16 @@ pub(crate) struct WasmOptConfig {
     /// Enable memory packing
     #[serde(default = "false_bool")]
     pub(crate) memory_packing: bool,
+
+    /// Extra arguments to pass to wasm-opt
+    ///
+    /// For example, to enable simd, you can set this to `["--enable-simd"]`.
+    ///
+    /// You can also disable features by prefixing them with `--disable-`, e.g. `["--disable-bulk-memory"]`.
+    ///
+    /// Currently only --enable and --disable flags are supported.
+    #[serde(default)]
+    pub(crate) extra_features: Vec<String>,
 }
 
 /// The wasm-opt level to use for release web builds [default: Z]
diff --git a/packages/cli/src/wasm_opt.rs b/packages/cli/src/wasm_opt.rs
index fa3607c0d..0d6e30a3f 100644
--- a/packages/cli/src/wasm_opt.rs
+++ b/packages/cli/src/wasm_opt.rs
@@ -26,9 +26,12 @@ pub async fn optimize(input_path: &Path, output_path: &Path, cfg: &WasmOptConfig
 }
 
 async fn run_locally(input_path: &Path, output_path: &Path, cfg: &WasmOptConfig) -> Result<()> {
+    // defaults needed by wasm-bindgen.
+    // wasm is a moving target, and we add these by default since they progressively get enabled by default.
     let mut args = vec![
-        // needed by wasm-bindgen
         "--enable-reference-types",
+        "--enable-bulk-memory",
+        "--enable-mutable-globals",
     ];
 
     if cfg.memory_packing {
@@ -43,6 +46,10 @@ async fn run_locally(input_path: &Path, output_path: &Path, cfg: &WasmOptConfig)
         args.push("--debuginfo");
     }
 
+    for extra in &cfg.extra_features {
+        args.push(extra);
+    }
+
     let level = match cfg.level {
         WasmOptLevel::Z => "-Oz",
         WasmOptLevel::S => "-Os",
@@ -72,6 +79,8 @@ async fn run_from_lib(
     output_path: &Path,
     options: &WasmOptConfig,
 ) -> Result<()> {
+    use std::str::FromStr;
+
     let mut level = match options.level {
         WasmOptLevel::Z => wasm_opt::OptimizationOptions::new_optimize_for_size_aggressively(),
         WasmOptLevel::S => wasm_opt::OptimizationOptions::new_optimize_for_size(),
@@ -84,8 +93,30 @@ async fn run_from_lib(
 
     level
         .enable_feature(wasm_opt::Feature::ReferenceTypes)
+        .enable_feature(wasm_opt::Feature::BulkMemory)
+        .enable_feature(wasm_opt::Feature::MutableGlobals)
         .add_pass(wasm_opt::Pass::MemoryPacking)
-        .debug_info(options.debug)
+        .debug_info(options.debug);
+
+    for arg in options.extra_features.iter() {
+        if arg.starts_with("--enable-") {
+            let feature = arg.trim_start_matches("--enable-");
+            if let Ok(feature) = wasm_opt::Feature::from_str(feature) {
+                level.enable_feature(feature);
+            } else {
+                tracing::warn!("Unknown wasm-opt feature: {}", feature);
+            }
+        } else if arg.starts_with("--disable-") {
+            let feature = arg.trim_start_matches("--disable-");
+            if let Ok(feature) = wasm_opt::Feature::from_str(feature) {
+                level.disable_feature(feature);
+            } else {
+                tracing::warn!("Unknown wasm-opt feature: {}", feature);
+            }
+        }
+    }
+
+    level
         .run(input_path, output_path)
         .map_err(|err| crate::Error::Other(anyhow::anyhow!(err)))?;