diff --git a/tools/web.py b/tools/web.py
index dea42b26b..fb173c3e2 100644
--- a/tools/web.py
+++ b/tools/web.py
@@ -46,6 +46,9 @@ def generate(env):
     env.Append(CCFLAGS=["-sSUPPORT_LONGJMP='wasm'"])
     env.Append(LINKFLAGS=["-sSUPPORT_LONGJMP='wasm'"])
 
+    # Use big int
+    env.Append(LINKFLAGS=["-sWASM_BIGINT"])
+
     env.Append(CPPDEFINES=["WEB_ENABLED", "UNIX_ENABLED"])
 
     common_compiler_flags.generate(env)