diff --git a/um_wasm_loader/build.js b/um_wasm_loader/build.js
index d689266..df4efda 100644
--- a/um_wasm_loader/build.js
+++ b/um_wasm_loader/build.js
@@ -62,7 +62,8 @@ async function main() {
   const wasmDistDir = path.resolve(__dirname, 'dist');
   await rm(wasmOutDir, { recursive: true, force: true });
   const wasmRelOutDir = path.relative(wasmSourceDir, wasmOutDir);
-  await run(['wasm-pack', 'build', '--target', 'web', '--out-dir', wasmRelOutDir], {
+  const profileFlag = process.env.BUILD_RELEASE ? '--release' : '--dev';
+  await run(['wasm-pack', 'build', profileFlag, '--target', 'web', '--out-dir', wasmRelOutDir], {
     cwd: path.resolve(__dirname, '..', 'um_wasm'),
   });