diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 441c673..232db9b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -31,3 +31,14 @@ jobs:
         run: pixi run pre-commit-all
       - name: Run unit tests
         run: pixi run test
+      - name: Run example notebook
+        run: |
+          pixi run serve-jupyter nbconvert \
+            --to notebook \
+            --execute \
+            --ExecutePreprocessor.store_widget_state=False \
+            --output "${PWD}/out.ipynb" \
+            examples/widgets.ipynb
+
+          # Widgets did render successufully as mime bundle
+          grep 'application/vnd.jupyter.ywidget-view+json' "${PWD}/out.ipynb"
diff --git a/R/comm.R b/R/comm.R
index 5bcbb4b..6438786 100644
--- a/R/comm.R
+++ b/R/comm.R
@@ -221,7 +221,8 @@ mime_bundle.CommWidget <- function(x, mimetypes = mime_types(x), ...) {
         model_id = x$comm_id()
       )
     ),
-    metadata = list()
+    # Serialize as dict, not list
+    metadata = structure(list(), names = character(0))
   )
 }
 
diff --git a/examples/widgets.ipynb b/examples/widgets.ipynb
new file mode 100644
index 0000000..fa2469a
--- /dev/null
+++ b/examples/widgets.ipynb
@@ -0,0 +1,149 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8ea1654d-6607-46dc-ad2f-60d58b451741",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# devtools::load_all(\".\")\n",
+    "\n",
+    "library(\"ywidget\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fc523884-6cdd-4191-84ea-cb2fafda18c2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "IntSlider <- make_comm_widget(\n",
+    "    \"IntSlider\",\n",
+    "    value = 50L,\n",
+    "    min = 0L,\n",
+    "    max = 100L,\n",
+    "    step = 1L\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "f0df5ce5-779b-4b8c-b338-3e5cab824318",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "s <- IntSlider$new()\n",
+    "s"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "359d9faa-7400-4548-b03e-641edc373b19",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "s$value"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "51225b68-1855-4557-9825-d76270e07468",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "s$value = 0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "1ce581d9-2932-40bd-92f0-8b7ab5e64610",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "s2 <- IntSlider$new()\n",
+    "s2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "163e7eb1-400b-4e54-9ca4-bb8186259c64",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "s"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "54f82252-6b3d-402f-8525-b4980ef4e5a8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "Textarea <- make_comm_widget(\n",
+    "    \"Textarea\",\n",
+    "    value = \"\",\n",
+    "    rows = 0L,\n",
+    "    disabled = FALSE,\n",
+    "    continuous_update = TRUE\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7c327b3f-9f81-4a94-a013-760b3ee9bc93",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "t <- Textarea$new()\n",
+    "t"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b8fa605f-e8f1-403a-a429-21ede9dfd29c",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "t$value"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "237427fd-6d51-4d8b-a85c-27a4a269a4d6",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "t$value <- \"Hello world!\""
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "R 4.4.3 (xr)",
+   "language": "R",
+   "name": "xr"
+  },
+  "language_info": {
+   "codemirror_mode": "",
+   "file_extension": ".R",
+   "mimetype": "text/x-R",
+   "name": "R",
+   "nbconvert_exporter": "",
+   "pygments_lexer": "r",
+   "version": "4.4.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/pixi.lock b/pixi.lock
index d3dc5e8..7ef50e5 100644
--- a/pixi.lock
+++ b/pixi.lock
@@ -819,7 +819,8 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/linux-64/xorg-libxrender-0.9.12-hb9d3cd8_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/xorg-libxt-1.3.1-hb9d3cd8_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/yaml-0.2.5-h280c20c_3.conda
-      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.1-pyhcf101f3_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-collection-0.5.1-pyh09b8992_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/zeromq-4.3.5-h41580af_10.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/zipp-3.23.1-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/linux-64/zstd-1.5.7-hb78ec9c_6.conda
@@ -1171,7 +1172,8 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/osx-64/xeus-r-0.11.0-r45h45edcf1_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-64/xeus-zmq-4.0.0-h695af4d_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-64/yaml-0.2.5-h4132b18_3.conda
-      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.1-pyhcf101f3_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-collection-0.5.1-pyh09b8992_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-64/zeromq-4.3.5-h27d9b8f_10.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/zipp-3.23.1-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-64/zlib-1.3.2-hbb4bfdb_2.conda
@@ -1524,7 +1526,8 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/xeus-r-0.11.0-r44he0f44cb_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/xeus-zmq-4.0.0-h5cc99d8_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/yaml-0.2.5-h925e9cb_3.conda
-      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.1-pyhcf101f3_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-collection-0.5.1-pyh09b8992_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/zeromq-4.3.5-h4818236_10.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/zipp-3.23.1-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/osx-arm64/zlib-1.3.2-h8088a28_2.conda
@@ -1855,7 +1858,8 @@ environments:
       - conda: https://conda.anaconda.org/conda-forge/win-64/xeus-r-0.11.0-r45h72f11de_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/xeus-zmq-4.0.0-hecdc818_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/yaml-0.2.5-h6a83c73_3.conda
-      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.0-pyhcf101f3_1.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.1-pyhcf101f3_0.conda
+      - conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-collection-0.5.1-pyh09b8992_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/zeromq-4.3.5-h507cc87_10.conda
       - conda: https://conda.anaconda.org/conda-forge/noarch/zipp-3.23.1-pyhcf101f3_0.conda
       - conda: https://conda.anaconda.org/conda-forge/win-64/zstd-1.5.7-h534d264_6.conda
@@ -13485,16 +13489,25 @@ packages:
   license_family: MIT
   size: 63944
   timestamp: 1753484092156
-- conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.0-pyhcf101f3_1.conda
-  sha256: 774bf6e7e2aacc57bfeae08151327a8f29739826cc96154f4f11d8cd5db47a1e
-  md5: 23dc2f4422c692df7e572ffc51ff473e
+- conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-0.5.1-pyhcf101f3_0.conda
+  sha256: b71a470cb5205e0917746b705434c25c00a45227ba2044469bd17de9500fadd0
+  md5: 0b9a1b6ac64d07fd43c783f0da66141e
   depends:
   - python >=3.10
   - python
   license: BSD-3-Clause
-  license_family: BSD
-  size: 38437
-  timestamp: 1778658872139
+  size: 38600
+  timestamp: 1779191003900
+- conda: https://conda.anaconda.org/conda-forge/noarch/yjs-widgets-collection-0.5.1-pyh09b8992_0.conda
+  sha256: a757728a193793799cfe58cee7f842fec86563127871de6f473506b7156114c6
+  md5: 635c6d948f936e415717fee074df379a
+  depends:
+  - yjs-widgets ==0.5.1 pyhcf101f3_0
+  - python >=3.10
+  - python
+  license: BSD-3-Clause
+  size: 31544
+  timestamp: 1779191003900
 - conda: https://conda.anaconda.org/conda-forge/linux-64/zeromq-4.3.5-h41580af_10.conda
   sha256: 325d370b28e2b9cc1f765c5b4cdb394c91a5d958fbd15da1a14607a28fee09f6
   md5: 755b096086851e1193f3b10347415d7c
diff --git a/pixi.toml b/pixi.toml
index c8c4112..ae1e498 100644
--- a/pixi.toml
+++ b/pixi.toml
@@ -30,6 +30,15 @@ typos = "*"
 pre-commit = "*"
 jupyterlab = ">=4"
 jupyterlab-kernelspy = "*"
+yjs-widgets = "*"
+yjs-widgets-collection = "*"
+
+[feature.dev.tasks.install-ywidget]
+cmd = "R CMD INSTALL ."
+
+[feature.dev.tasks.serve-jupyter]
+cmd = "jupyter"
+depends-on = ["install-ywidget"]
 
 [feature.dev.tasks]
 # Document