diff --git a/Source/Engine/Serialization/Json.h b/Source/Engine/Serialization/Json.h
index d691085f3..6f300f3ae 100644
--- a/Source/Engine/Serialization/Json.h
+++ b/Source/Engine/Serialization/Json.h
@@ -5,7 +5,9 @@
 #include "Engine/Core/Types/String.h"
 #include "Engine/Core/Types/StringView.h"
 
-#if PLATFORM_SIMD_SSE4_2
+#if PLATFORM_WEB
+#define RAPIDJSON_SSE2
+#elif PLATFORM_SIMD_SSE4_2
 #define RAPIDJSON_SSE42
 #elif PLATFORM_SIMD_SSE2
 #define RAPIDJSON_SSE2
diff --git a/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs b/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
index 115c67fed..b10a3b272 100644
--- a/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
+++ b/Source/Tools/Flax.Build/Platforms/Web/WebToolchain.cs
@@ -95,7 +95,7 @@ namespace Flax.Build.Platforms
             options.CompileEnv.PreprocessorDefinitions.Add("PLATFORM_UNIX");
             options.CompileEnv.PreprocessorDefinitions.Add("__EMSCRIPTEN__");
             options.CompileEnv.EnableExceptions = false;
-            options.CompileEnv.CpuArchitecture = CpuArchitecture.None; // TODO: try SIMD support in Emscripten
+            options.CompileEnv.CpuArchitecture = CpuArchitecture.SSE4_2;
         }
 
         private void AddSharedArgs(List<string> args, BuildOptions options, bool debugInformation, bool optimization)
@@ -129,6 +129,27 @@ namespace Flax.Build.Platforms
             else
                 args.Add("-fno-exceptions");
 
+            if (options.CompileEnv.CpuArchitecture != CpuArchitecture.None)
+                args.Add("-msimd128 -mno-nontrapping-fptoint");
+            switch (options.CompileEnv.CpuArchitecture)
+            {
+            case CpuArchitecture.AVX:
+                args.Add("-mavx");
+                break;
+            case CpuArchitecture.AVX2:
+                args.Add("-mavx2");
+                break;
+            case CpuArchitecture.SSE2:
+                args.Add("-msse2");
+                break;
+            case CpuArchitecture.SSE4_2:
+                args.Add("-msse4.2");
+                break;
+            case CpuArchitecture.NEON:
+                args.Add("-mfpu=neon");
+                break;
+            }
+
             if (options.LinkEnv.LinkTimeCodeGeneration)
                 args.Add("-flto");