diff --git a/vm/src/stdlib/json.rs b/vm/src/stdlib/json.rs
index 84b82389ed9..81fb364d48d 100644
--- a/vm/src/stdlib/json.rs
+++ b/vm/src/stdlib/json.rs
@@ -188,15 +188,36 @@ impl<'de> Visitor<'de> for PyObjectDeserializer<'de> {
     }
 }
 
+pub fn ser_pyobject(vm: &mut VirtualMachine, obj: &PyObjectRef) -> PyResult<String> {
+    let serializer = PyObjectSerializer { pyobject: obj, vm };
+    serde_json::to_string(&serializer).map_err(|err| vm.new_type_error(err.to_string()))
+}
+
+pub fn de_pyobject(vm: &mut VirtualMachine, s: &str) -> PyResult {
+    let de = PyObjectDeserializer { vm };
+    // TODO: Support deserializing string sub-classes
+    de.deserialize(&mut serde_json::Deserializer::from_str(s))
+        .map_err(|err| {
+            let json_decode_error = vm
+                .sys_module
+                .get_item("modules")
+                .unwrap()
+                .get_item("json")
+                .unwrap()
+                .get_item("JSONDecodeError")
+                .unwrap();
+            let exc = vm.new_exception(json_decode_error, format!("{}", err));
+            vm.ctx.set_attr(&exc, "lineno", vm.ctx.new_int(err.line()));
+            vm.ctx.set_attr(&exc, "colno", vm.ctx.new_int(err.column()));
+            exc
+        })
+}
+
 /// Implement json.dumps
 fn json_dumps(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     // TODO: Implement non-trivial serialisation case
     arg_check!(vm, args, required = [(obj, None)]);
-    let res = {
-        let serializer = PyObjectSerializer { pyobject: obj, vm };
-        serde_json::to_string(&serializer)
-    };
-    let string = res.map_err(|err| vm.new_type_error(format!("{}", err)))?;
+    let string = ser_pyobject(vm, obj)?;
     Ok(vm.context().new_str(string))
 }
 
@@ -204,28 +225,8 @@ fn json_dumps(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 fn json_loads(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     // TODO: Implement non-trivial deserialization case
     arg_check!(vm, args, required = [(string, Some(vm.ctx.str_type()))]);
-    let res = {
-        let de = PyObjectDeserializer { vm };
-        // TODO: Support deserializing string sub-classes
-        de.deserialize(&mut serde_json::Deserializer::from_str(&objstr::get_value(
-            &string,
-        )))
-    };
-
-    res.map_err(|err| {
-        let json_decode_error = vm
-            .sys_module
-            .get_item("modules")
-            .unwrap()
-            .get_item("json")
-            .unwrap()
-            .get_item("JSONDecodeError")
-            .unwrap();
-        let exc = vm.new_exception(json_decode_error, format!("{}", err));
-        vm.ctx.set_attr(&exc, "lineno", vm.ctx.new_int(err.line()));
-        vm.ctx.set_attr(&exc, "colno", vm.ctx.new_int(err.column()));
-        exc
-    })
+
+    de_pyobject(vm, &objstr::get_value(&string))
 }
 
 pub fn make_module(ctx: &PyContext) -> PyObjectRef {
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index c3bb543f524..b0b61119c3e 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -1,6 +1,6 @@
 mod ast;
 mod dis;
-mod json;
+pub(crate) mod json;
 mod keyword;
 mod math;
 mod platform;
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
index ac97e8e9c3e..f78d657ccf9 100644
--- a/vm/src/vm.rs
+++ b/vm/src/vm.rs
@@ -626,6 +626,14 @@ impl VirtualMachine {
         })
     }
 
+    pub fn serialize(&mut self, obj: &PyObjectRef) -> PyResult<String> {
+        crate::stdlib::json::ser_pyobject(self, obj)
+    }
+
+    pub fn deserialize(&mut self, s: &str) -> PyResult {
+        crate::stdlib::json::de_pyobject(self, s)
+    }
+
     pub fn _sub(&mut self, a: PyObjectRef, b: PyObjectRef) -> PyResult {
         self.call_or_reflection(a, b, "__sub__", "__rsub__", |vm, a, b| {
             Err(vm.new_unsupported_operand_error(a, b, "-"))
diff --git a/wasm/lib/src/convert.rs b/wasm/lib/src/convert.rs
index 1cf8907681b..1113ace8783 100644
--- a/wasm/lib/src/convert.rs
+++ b/wasm/lib/src/convert.rs
@@ -111,13 +111,14 @@ pub fn py_to_js(vm: &mut VirtualMachine, py_obj: PyObjectRef) -> JsValue {
 
             return func;
         }
-        // the browser module might not be injected
-        if let Ok(promise_type) = browser_module::import_promise_type(vm) {
-            if objtype::isinstance(&py_obj, &promise_type) {
-                return browser_module::get_promise_value(&py_obj).into();
-            }
+    }
+    // the browser module might not be injected
+    if let Ok(promise_type) = browser_module::import_promise_type(vm) {
+        if objtype::isinstance(&py_obj, &promise_type) {
+            return browser_module::get_promise_value(&py_obj).into();
         }
     }
+
     if objtype::isinstance(&py_obj, &vm.ctx.bytes_type())
         || objtype::isinstance(&py_obj, &vm.ctx.bytearray_type())
     {
@@ -129,12 +130,8 @@ pub fn py_to_js(vm: &mut VirtualMachine, py_obj: PyObjectRef) -> JsValue {
         }
         arr.into()
     } else {
-        let dumps = vm.class("json", "dumps");
-        match vm.invoke(dumps, PyFuncArgs::new(vec![py_obj], vec![])) {
-            Ok(value) => {
-                let json = vm.to_pystr(&value).unwrap();
-                js_sys::JSON::parse(&json).unwrap_or(JsValue::UNDEFINED)
-            }
+        match vm.serialize(&py_obj) {
+            Ok(json) => js_sys::JSON::parse(&json).unwrap_or(JsValue::UNDEFINED),
             Err(_) => JsValue::UNDEFINED,
         }
     }
@@ -226,15 +223,10 @@ pub fn js_to_py(vm: &mut VirtualMachine, js_val: JsValue) -> PyObjectRef {
         // Because `JSON.stringify(undefined)` returns undefined
         vm.get_none()
     } else {
-        let loads = vm.class("json", "dumps");
         let json = match js_sys::JSON::stringify(&js_val) {
             Ok(json) => String::from(json),
             Err(_) => return vm.get_none(),
         };
-        let py_json = vm.new_str(json);
-
-        vm.invoke(loads, PyFuncArgs::new(vec![py_json], vec![]))
-            // can safely unwrap because we know it's valid JSON
-            .unwrap()
+        vm.deserialize(&json).unwrap_or_else(|_| vm.get_none())
     }
 }