diff --git a/hugr-py/src/hugr/hugr.py b/hugr-py/src/hugr/_hugr.py
similarity index 100%
rename from hugr-py/src/hugr/hugr.py
rename to hugr-py/src/hugr/_hugr.py
diff --git a/hugr-py/src/hugr/ops.py b/hugr-py/src/hugr/ops.py
new file mode 100644
index 000000000..c645d0664
--- /dev/null
+++ b/hugr-py/src/hugr/ops.py
@@ -0,0 +1,135 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass, field
+from typing import Generic, TypeVar, TYPE_CHECKING
+from hugr.serialization.ops import BaseOp, OpType as SerialOp
+import hugr.serialization.ops as sops
+import hugr.serialization.tys as tys
+
+if TYPE_CHECKING:
+    from hugr._hugr import Hugr, Node
+
+
+class Op(ABC):
+    @abstractmethod
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp: ...
+
+    @classmethod
+    def from_serial(cls, serial: SerialOp) -> Op:
+        match serial.root:
+            case sops.Input(types=types):
+                return Input(types=types)
+            case sops.Output(types=types):
+                return Output(types=types)
+            case sops.CustomOp(
+                extension=extension,
+                op_name=op_name,
+                signature=signature,
+                description=description,
+                args=args,
+            ):
+                return Custom(
+                    extension=extension,
+                    op_name=op_name,
+                    signature=signature,
+                    description=description,
+                    args=args,
+                )
+            case sops.MakeTuple(tys=types):
+                return MakeTuple(types=types)
+            case sops.UnpackTuple(tys=types):
+                return UnpackTuple(types=types)
+            case sops.DFG(signature=signature):
+                return DFG(signature=signature)
+        return SerWrap(serial.root)
+
+
+T = TypeVar("T", bound=BaseOp)
+
+
+@dataclass()
+class SerWrap(Op, Generic[T]):
+    # catch all for serial ops that don't have a corresponding Op class
+    _serial_op: T
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        root = self._serial_op.model_copy()
+        root.parent = parent.idx
+        return SerialOp(root=root)  # type: ignore
+
+
+@dataclass()
+class Input(Op):
+    types: list[tys.Type]
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(root=sops.Input(parent=parent.idx, types=self.types))
+
+
+@dataclass()
+class Output(Op):
+    types: list[tys.Type]
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(root=sops.Output(parent=parent.idx, types=self.types))
+
+
+@dataclass()
+class Custom(Op):
+    extension: tys.ExtensionId
+    op_name: str
+    signature: tys.FunctionType = field(default_factory=tys.FunctionType.empty)
+    description: str = ""
+    args: list[tys.TypeArg] = field(default_factory=list)
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(
+            root=sops.CustomOp(
+                parent=parent.idx,
+                extension=self.extension,
+                op_name=self.op_name,
+                signature=self.signature,
+                description=self.description,
+                args=self.args,
+            )
+        )
+
+
+@dataclass()
+class MakeTuple(Op):
+    types: list[tys.Type]
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(
+            root=sops.MakeTuple(
+                parent=parent.idx,
+                tys=self.types,
+            )
+        )
+
+
+@dataclass()
+class UnpackTuple(Op):
+    types: list[tys.Type]
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(
+            root=sops.UnpackTuple(
+                parent=parent.idx,
+                tys=self.types,
+            )
+        )
+
+
+@dataclass()
+class DFG(Op):
+    signature: tys.FunctionType = field(default_factory=tys.FunctionType.empty)
+
+    def to_serial(self, node: Node, parent: Node, hugr: Hugr) -> SerialOp:
+        return SerialOp(
+            root=sops.DFG(
+                parent=parent.idx,
+                signature=self.signature,
+            )
+        )
diff --git a/hugr-py/tests/test_hugr_build.py b/hugr-py/tests/test_hugr_build.py
index 830e5734e..522da06f6 100644
--- a/hugr-py/tests/test_hugr_build.py
+++ b/hugr-py/tests/test_hugr_build.py
@@ -3,7 +3,7 @@
 import subprocess
 import os
 import pathlib
-from hugr.hugr import Dfg, Hugr, DummyOp, Node, Command, Wire, Op
+from hugr._hugr import Dfg, Hugr, DummyOp, Node, Command, Wire, Op
 from hugr.serialization import SerialHugr
 import hugr.serialization.tys as stys
 import hugr.serialization.ops as sops