diff --git a/py/h2o_nitro/core.py b/py/h2o_nitro/core.py
index 7d6a5694..a05d9035 100644
--- a/py/h2o_nitro/core.py
+++ b/py/h2o_nitro/core.py
@@ -17,12 +17,32 @@
 import random
 from pathlib import Path
 from collections import OrderedDict
-import msgpack
 from enum import Enum, IntEnum
-from .version import __version__
+from .version import __version__, __nitride__
 
 web_directory = str(Path(__file__).parent / 'www')
 
+if __nitride__:
+    import json
+
+
+    def _marshal(d: dict):
+        return json.dumps(d)
+
+
+    def _unmarshal(b) -> dict:
+        return json.loads(b)
+else:
+    import msgpack
+
+
+    def _marshal(d: dict):
+        return msgpack.packb(d)
+
+
+    def _unmarshal(b) -> dict:
+        return msgpack.unpackb(b)
+
 __xid = 0
 
 
@@ -71,14 +91,6 @@ def __init__(self):
         super().__init__('Interrupted')
 
 
-def _marshal(d: dict):
-    return msgpack.packb(d)
-
-
-def _unmarshal(b) -> dict:
-    return msgpack.unpackb(b)
-
-
 def _dump(x):  # recursive
     if isinstance(x, OrderedDict):
         return _dump([(k, v) for k, v in x.items()])
@@ -607,7 +619,7 @@ def _unwrap_input(x):
     return None if x is None else x[1]
 
 
-def _marshal_error(code: int, text: str) -> dict:
+def _marshal_error(code: int, text: str):
     return _marshal(dict(t=_MsgType.Error, code=code, text=text))
 
 
@@ -619,7 +631,7 @@ def _marshal_set(
         theme: Optional[Theme] = None,
         plugins: Optional[Iterable[Plugin]] = None,
         mode: Optional[str] = None,
-) -> dict:
+):
     return _marshal(dict(
         t=_MsgType.Set,
         xid=_xid(),
diff --git a/py/h2o_nitro/version.py b/py/h2o_nitro/version.py
index 1f4c4d43..afe6f02a 100644
--- a/py/h2o_nitro/version.py
+++ b/py/h2o_nitro/version.py
@@ -1 +1,2 @@
 __version__ = "0.10.1"
+__nitride__ = False
diff --git a/web/public/nitride.js b/web/public/nitride.js
new file mode 100644
index 00000000..8f416e91
--- /dev/null
+++ b/web/public/nitride.js
@@ -0,0 +1,34 @@
+
+const pollInterval = 100
+
+let _poller = 0;
+
+async function init(runtime, program, autoload) {
+  importScripts(runtime);
+  self.pyodide = await loadPyodide();
+  await self.pyodide.loadPackage(["micropip"]);
+  if (autoload) await self.pyodide.loadPackagesFromImports(program);
+  await self.pyodide.runPythonAsync(program);
+  clearInterval(_poller);
+  _poller = setInterval(() => {
+    const message = self.pyodide.globals.get('_nitro_io').read();
+    if (message) self.postMessage({ t: 1, message });
+  }, pollInterval);
+}
+
+self.onmessage = async (event) => {
+  const c = event.data;
+  try {
+    switch (c.t) {
+      case 1:
+        self.pyodide.globals.get('_nitro_io').write(c.message);
+        break;
+      case 2:
+        await init(c.runtime, c.program, c.autoload);
+        self.postMessage({ t: 3 });
+        break;
+    }
+  } catch (error) {
+    self.postMessage({ t: 0, error: error.message });
+  }
+}