diff --git a/pyproject.toml b/pyproject.toml
index e38a537..43fbb6c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -104,10 +104,12 @@ ignore = [
     "E402", # Module level import not at top of file
     "E731", # Do not assign a lambda expression, use a def
     "E741", # Ambiguous variable name
+    "PLR2004", # magic-value-comparison
 ]
 fix = true
 unfixable = [
     "F401", # unused imports
+    "F841", # unused variables
 ]
 
 [tool.ruff.per-file-ignores]
diff --git a/src/clean_notebook/clean.py b/src/clean_notebook/clean.py
index a89b0fe..fc0935f 100644
--- a/src/clean_notebook/clean.py
+++ b/src/clean_notebook/clean.py
@@ -1,9 +1,12 @@
 from __future__ import annotations
 
 import json
+import uuid
 from pathlib import Path
 from typing import Any, AnyStr, Iterator
 
+__all__ = ("clean_notebook", "clean_single_notebook")
+
 
 def clean_notebook(
     paths: list[str | Path],
@@ -29,6 +32,11 @@ def find_line_ending(s: AnyStr) -> AnyStr:
     return counter[max(counter)]
 
 
+def _check_set_id(nb: dict[str, Any]) -> bool:
+    # https://jupyter.org/enhancement-proposals/62-cell-id/cell-id.html
+    return (nb["nbformat"] == 4 and nb["nbformat_minor"] >= 5) or nb["nbformat"] >= 5
+
+
 def clean_single_notebook(
     file: Path,
     *,
@@ -42,6 +50,7 @@ def clean_single_notebook(
     newline = find_line_ending(raw)
     nb = json.loads(raw)
 
+    set_id = _check_set_id(nb)
     cleaned = False
     for cell in nb["cells"].copy():
         cleaned |= _update_value(cell, "outputs", [])
@@ -53,6 +62,9 @@ def clean_single_notebook(
         if "attachments" in cell and len(cell["attachments"]) == 0:
             del cell["attachments"]
             cleaned = True
+        if set_id and cell.get("id") is None:
+            cell["id"] = str(uuid.uuid4())
+            cleaned = True
 
     if not nb["cells"]:
         print(f"Notebook '{file}' does not have any valid cells.")
@@ -63,7 +75,7 @@ def clean_single_notebook(
 
     if cleaned and not dryrun:
         with open(file, "w", encoding="utf8", newline=newline) as f:
-            json.dump(nb, f, indent=1, ensure_ascii=False)
+            json.dump(nb, f, indent=1, ensure_ascii=False, sort_keys=True)
             f.write(newline)  # empty line at the end of the file
         print(f"Cleaned notebook: {file}")
     elif cleaned:
diff --git a/tests/data/clean_colab.ipynb b/tests/data/clean_colab.ipynb
index 38eb476..b83cb28 100644
--- a/tests/data/clean_colab.ipynb
+++ b/tests/data/clean_colab.ipynb
@@ -1,12 +1,4 @@
 {
- "nbformat": 4,
- "nbformat_minor": 0,
- "metadata": {
-  "language_info": {
-   "name": "python",
-   "pygments_lexer": "ipython3"
-  }
- },
  "cells": [
   {
    "cell_type": "code",
@@ -21,21 +13,29 @@
   },
   {
    "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
    "source": [
     "print(\"saved from colab\")"
-   ],
-   "metadata": {},
-   "execution_count": null,
-   "outputs": []
+   ]
   },
   {
    "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
    "source": [
     ""
-   ],
-   "metadata": {},
-   "execution_count": null,
-   "outputs": []
+   ]
   }
- ]
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
 }
diff --git a/tests/data/clean_id.ipynb b/tests/data/clean_id.ipynb
new file mode 100644
index 0000000..3a83443
--- /dev/null
+++ b/tests/data/clean_id.ipynb
@@ -0,0 +1,38 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3d183bd1-509f-4758-9f2d-db94b23c58f9",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "a = 2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "66cdc779-4931-4306-881a-4bf30cb0fdbb",
+   "metadata": {},
+   "source": [
+    "Markdown"
+   ]
+  },
+  {
+   "cell_type": "raw",
+   "id": "5cbb8154-79ee-4290-953c-89a89b4276b7",
+   "metadata": {},
+   "source": [
+    "Raw"
+   ]
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/tests/data/dirty_id.ipynb b/tests/data/dirty_id.ipynb
new file mode 100644
index 0000000..b1fa9f7
--- /dev/null
+++ b/tests/data/dirty_id.ipynb
@@ -0,0 +1,42 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "a = 2"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Markdown"
+   ]
+  },
+  {
+   "cell_type": "raw",
+   "metadata": {},
+   "source": [
+    "Raw"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "name": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/tests/test_clean_notebook.py b/tests/test_clean_notebook.py
index 6be68e1..8c874c6 100644
--- a/tests/test_clean_notebook.py
+++ b/tests/test_clean_notebook.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import uuid
 from pathlib import Path
 from shutil import copy2, rmtree
 from typing import TYPE_CHECKING, Iterator
@@ -10,6 +11,7 @@
 
 if TYPE_CHECKING:
     from _pytest.capture import CaptureFixture
+    from _pytest.monkeypatch import MonkeyPatch
     from _pytest.tmpdir import TempPathFactory
 
 
@@ -34,7 +36,7 @@ def temp_path(tmp_path_factory: TempPathFactory) -> Iterator[Path]:
 TESTS = ["ascii", "jupyterlab", "vscode", "colab", "empty_cell", "empty_multi_cell"]
 
 
-@pytest.mark.parametrize("test", [*TESTS, "ignore_slideshow"])
+@pytest.mark.parametrize("test", [*TESTS, "ignore_slideshow", "id"])
 def test_noclean_notebook(temp_path: Path, test: str) -> None:
     dirty = temp_path / f"dirty_{test}.ipynb"
     clean = temp_path / f"clean_{test}.ipynb"
@@ -74,6 +76,31 @@ def test_ignore_metadata(temp_path: Path) -> None:
     assert clean_bytes != dirty_bytes
 
 
+def test_notebook_id(temp_path: Path, monkeypatch: MonkeyPatch) -> None:
+    test = "id"
+    dirty = temp_path / f"dirty_{test}.ipynb"
+    clean = temp_path / f"clean_{test}.ipynb"
+
+    ids = [
+        "3d183bd1-509f-4758-9f2d-db94b23c58f9",
+        "66cdc779-4931-4306-881a-4bf30cb0fdbb",
+        "5cbb8154-79ee-4290-953c-89a89b4276b7",
+    ]
+    iterator = iter(ids)
+    monkeypatch.setattr(uuid, "uuid4", lambda: next(iterator))
+
+    clean_single_notebook(dirty)
+    clean_bytes = load_file(clean)
+    dirty_bytes = load_file(dirty)
+    assert clean_bytes == dirty_bytes
+
+
+def test_notebook_no_overwrite_ids(temp_path: Path) -> None:
+    test = "id"
+    clean = temp_path / f"clean_{test}.ipynb"
+    assert not clean_single_notebook(clean)
+
+
 def test_empty_notebook(capsys: CaptureFixture[str], temp_path: Path) -> None:
     dirty = temp_path / "dirty_empty.ipynb"