diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6be026fa..1e4d6df7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -87,8 +87,8 @@ if (EMSCRIPTEN)
   set(ZLIB_LIBRARIES)
   set(ZLIB_INCLUDE_DIR)
 
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Os -s ALLOW_MEMORY_GROWTH=1 -s MEMFS_APPEND_TO_TYPED_ARRAYS=1 -s USE_ZLIB=1 -s MODULARIZE=1 -s WEBSOCKET_URL=\"'wss:#'\" -s EXTRA_EXPORTED_RUNTIME_METHODS=\"['FS','cwrap']\"")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Os -s ALLOW_MEMORY_GROWTH=1 -s MEMFS_APPEND_TO_TYPED_ARRAYS=1 -s USE_ZLIB=1 -s MODULARIZE=1 -s WEBSOCKET_URL=\"'wss:#'\" -s EXTRA_EXPORTED_RUNTIME_METHODS=\"['FS','cwrap']\"")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -s ALLOW_MEMORY_GROWTH=1 -s MEMFS_APPEND_TO_TYPED_ARRAYS=1 -s USE_ZLIB=1 -s MODULARIZE=1 -s WEBSOCKET_URL=\"'wss:#'\" -s EXTRA_EXPORTED_RUNTIME_METHODS=\"['FS','cwrap']\"")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -s ALLOW_MEMORY_GROWTH=1 -s MEMFS_APPEND_TO_TYPED_ARRAYS=1 -s USE_ZLIB=1 -s MODULARIZE=1 -s WEBSOCKET_URL=\"'wss:#'\" -s EXTRA_EXPORTED_RUNTIME_METHODS=\"['FS','cwrap']\"")
   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -s DEMANGLE_SUPPORT=1 -s ASSERTIONS=1")
   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -s DEMANGLE_SUPPORT=1 -s ASSERTIONS=1")
 
diff --git a/example/web/build-tdlib.sh b/example/web/build-tdlib.sh
index 548c77e3..da24706f 100755
--- a/example/web/build-tdlib.sh
+++ b/example/web/build-tdlib.sh
@@ -29,11 +29,11 @@ cmake $TD_ROOT || exit 1
 cd ../..
 
 cd build/wasm
-eval emconfigure cmake -DCMAKE_BUILD_TYPE=Release $OPENSSL_OPTIONS $TD_ROOT || exit 1
+eval emconfigure cmake -DCMAKE_BUILD_TYPE=MinSizeRel $OPENSSL_OPTIONS $TD_ROOT || exit 1
 cd ../..
 
 cd build/asmjs
-eval emconfigure cmake -DCMAKE_BUILD_TYPE=Release $OPENSSL_OPTIONS -DASMJS=1 $TD_ROOT || exit 1
+eval emconfigure cmake -DCMAKE_BUILD_TYPE=MinSizeRel $OPENSSL_OPTIONS -DASMJS=1 $TD_ROOT || exit 1
 cd ../..
 
 echo "Generating TDLib autogenerated source files..."
diff --git a/example/web/tdweb/package.json b/example/web/tdweb/package.json
index 7d51ea19..6401dc14 100644
--- a/example/web/tdweb/package.json
+++ b/example/web/tdweb/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@arseny30/tdweb",
-  "version": "0.2.42",
+  "version": "0.2.43",
   "description": "Javascript interface for TDLib (telegram library)",
   "main": "dist/tdweb.js",
   "files": [