diff --git a/CHANGELOG.md b/CHANGELOG.md
index f95f81f8..3731aaed 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,13 +14,14 @@
 
 #### @deathbeds/ipydrawio 1.2.0
 
+- adds support for data URI-encoded shape libraries (incompatible with `stealth`) [#80]
 - fixes selection in widget diagrams with more than 10 shapes [#85]
 
 #### @deathbeds/ipydrawio-notebook 1.2.0
 
-#### @deathbeds/ipydrawio-webpack 16.4.0
+#### @deathbeds/ipydrawio-webpack 16.4.500
 
-- updates to drawio v16.4.0
+- updates to drawio v16.4.5
 
 #### @deathbeds/ipydrawio-jupyter-templates 1.2.0
 
@@ -31,6 +32,7 @@
 #### @deathbeds/ipydrawio-pdf 1.2.0
 
 [#63]: https://github.com/deathbeds/ipydrawio/issues/63
+[#80]: https://github.com/deathbeds/ipydrawio/issues/80
 [#85]: https://github.com/deathbeds/ipydrawio/issues/85
 [#88]: https://github.com/deathbeds/ipydrawio/issues/88
 
diff --git a/atest/_Variables.robot b/atest/_Variables.robot
index 8338fdab..0dfdb1be 100644
--- a/atest/_Variables.robot
+++ b/atest/_Variables.robot
@@ -97,3 +97,6 @@ ${XP DIO PAGE SIZE}    //div[contains(@class, "geFormatSection")][contains(., "P
 ${MIME STDERR}    application/vnd.jupyter.stderr
 # retro
 ${CSS RETRO TREE DIO BTN}    css:button[title='${CREATE A BLANK}']
+# docs
+${TUTORIALS}      ${ROOT}${/}docs${/}tutorials
+${CLIB TUTORIAL}    ${TUTORIALS}${/}working-with-custom-libraries${/}index.ipynb
diff --git a/atest/lab/Tutorials.robot b/atest/lab/Tutorials.robot
new file mode 100644
index 00000000..85855884
--- /dev/null
+++ b/atest/lab/Tutorials.robot
@@ -0,0 +1,51 @@
+# Copyright 2022 ipydrawio contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#                 http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+*** Settings ***
+Documentation     Do the tutorials work?
+Resource          ../_Keywords.robot
+Library           OperatingSystem
+Force Tags        component:tutorials
+Suite Setup       Set Screenshot Directory    ${OUTPUT DIR}${/}screenshots${/}tutorials
+
+*** Variables ***
+${XP MY LIBRARY TITLE}    xpath://a[starts-with(@title, 'my+library')]
+${XP MY LIBRARY SHAPES}    ${XP MY LIBRARY TITLE}/following-sibling::div[1]//a[contains(@class, 'geItem')]
+${XP SHAPE TOOLTIP}    xpath://*[contains(@class, 'geSidebarTooltip')]
+@{SHAPE TITLES}    Exit    Machine    Queue    Source
+
+*** Test Cases ***
+Custom Library URL Hack
+    [Documentation]    Does using a custom library work?
+    [Tags]    component:widget
+    Copy File    ${CLIB TUTORIAL}    ${HOME}${/}clib.ipynb
+    Wait Until Keyword Succeeds    5x    5s    Open clib.ipynb in ${MENU NOTEBOOK}
+    Lab Command    Restart Kernel and Run All Cells
+    Accept Default Dialog Option
+    Click Element    css:.jp-Cell:last-child
+    Wait Until Keyword Succeeds    5x    5s    Wait for a Diagram to be Ready
+    Wait Until Page Contains Element    ${XP MY LIBRARY TITLE}
+    ${shapes} =    Get WebElements    ${XP MY LIBRARY SHAPES}
+    Should be Equal as Integers    ${shapes.__len__()}    4
+    FOR    ${idx}    ${shape}    IN ENUMERATE    ${shapes}
+        Mouse Over    ${shape}
+        Wait Until Page Contains Element
+        ...    ${XP SHAPE TOOLTIP}\[contains(., '${SHAPE TITLES[${idx}]}')]
+    END
+    [Teardown]    Tear Down Custom Library Tutorial
+
+*** Keywords ***
+Tear Down Custom Library Tutorial
+    Unselect Frame
+    Remove File    ${HOME}${/}clib.ipynb
diff --git a/docs/tutorials/index.md b/docs/tutorials/index.md
index f51355f1..e51062ef 100644
--- a/docs/tutorials/index.md
+++ b/docs/tutorials/index.md
@@ -3,6 +3,7 @@
 ```{toctree}
 :maxdepth: 2
 designing-jupyter-extensions/index
+working-with-custom-libraries/index
 ```
 
 <!--
diff --git a/docs/tutorials/working-with-custom-libraries/index.ipynb b/docs/tutorials/working-with-custom-libraries/index.ipynb
new file mode 100644
index 00000000..2d633012
--- /dev/null
+++ b/docs/tutorials/working-with-custom-libraries/index.ipynb
@@ -0,0 +1,300 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "e9738510-4036-46e9-b728-4590dbd2c738",
+   "metadata": {},
+   "source": [
+    "# Working with Custom Shape Libraries\n",
+    "\n",
+    "When working with the `ipydrawio` TypeScript API, custom shape libraries can be added by providing a fully-resolved, absolute URL to an `.xml` file in `clibs`. \n",
+    "\n",
+    "From the [Widget API](../../Diagram%20Widget.ipynb), this is somewhat more complicated, but might be worth it for certain custom cases such as [issue #80](https://github.com/deathbeds/ipydrawio/issues/80), where a fully-kernel-driven solution is desirable, despite the _gotchas_ (see below)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ff64bdc4-2dd5-4738-affc-36dab7c82584",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import base64, json, urllib.parse, zlib\n",
+    "import ipydrawio"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "6f54b3ce-a88a-4a89-bebb-3074ad6dfee4",
+   "metadata": {},
+   "source": [
+    "## A Library\n",
+    "A library is, at its core, a list of shape descriptions. The best way to learn more about these is investigating the [drawio documentation](https://www.diagrams.net/blog/custom-libraries), which covers building them interactively. When done, you'd end up with some data like this."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8c582ec1-23ca-4e76-8733-cf8d8d7d8b46",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "library = [\n",
+    "    {\n",
+    "        \"w\": 80,\n",
+    "        \"h\": 80,\n",
+    "        \"aspect\": \"fixed\",\n",
+    "        \"title\": \"Source\",\n",
+    "        \"xml\": '<mxGraphModel><root><mxCell id=\"0\"/><mxCell id=\"1\" parent=\"0\"/><object label=\"\" type=\"Source\" interArrivalTime=\"\" id=\"2\"><mxCell style=\"rhombus;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object></root></mxGraphModel>',\n",
+    "    },\n",
+    "    {\n",
+    "        \"w\": 80,\n",
+    "        \"h\": 80,\n",
+    "        \"aspect\": \"fixed\",\n",
+    "        \"title\": \"Queue\",\n",
+    "        \"xml\": '<mxGraphModel><root><mxCell id=\"0\"/><mxCell id=\"1\" parent=\"0\"/><object label=\"\" type=\"Queue\" capacity=\"\" id=\"2\"><mxCell style=\"ellipse;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object></root></mxGraphModel>',\n",
+    "    },\n",
+    "    {\n",
+    "        \"w\": 80,\n",
+    "        \"h\": 80,\n",
+    "        \"aspect\": \"fixed\",\n",
+    "        \"title\": \"Machine\",\n",
+    "        \"xml\": '<mxGraphModel><root><mxCell id=\"0\"/><mxCell id=\"1\" parent=\"0\"/><object label=\"\" type=\"Machine\" processingTime=\"\" id=\"2\"><mxCell style=\"whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object></root></mxGraphModel>',\n",
+    "    },\n",
+    "    {\n",
+    "        \"w\": 80,\n",
+    "        \"h\": 80,\n",
+    "        \"aspect\": \"fixed\",\n",
+    "        \"title\": \"Exit\",\n",
+    "        \"xml\": '<mxGraphModel><root><mxCell id=\"0\"/><mxCell id=\"1\" parent=\"0\"/><object label=\"\" type=\"Exit\" id=\"2\"><mxCell style=\"rhombus;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object></root></mxGraphModel>',\n",
+    "    },\n",
+    "]\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "708fb970-bade-40a2-a495-b861ebadfbd3",
+   "metadata": {},
+   "source": [
+    "## JSON Encoding"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3c5665cf-9a04-4f28-b27d-7bd9cf880b2a",
+   "metadata": {},
+   "source": [
+    "Each element in the list has an `xml` attribute which is, as it suggests, XML, and must be carefully escaped. Because this will go through a URL parser, an XML parser, a JSON parser, and then another XML parser, the recommended approach is to use drawio's semi-convoluted base64/zlib technique."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3e9a519c-a868-4d71-885e-fcafe41915fa",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "zlib_opts = dict(wbits=-15)\n",
+    "\n",
+    "def inflate(deflated):\n",
+    "    infl = zlib.decompressobj(**zlib_opts)\n",
+    "    return urllib.parse.unquote(infl.decompress(base64.b64decode(deflated)) + infl.flush())\n",
+    "\n",
+    "def deflate(inflated):\n",
+    "    defl = zlib.compressobj(**zlib_opts)\n",
+    "    return base64.b64encode(defl.compress(urllib.parse.quote(inflated).encode(\"utf-8\")) + defl.flush()).decode('utf-8')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "0a33277f-abd0-4b97-a803-ad2ed82a6222",
+   "metadata": {},
+   "source": [
+    "Again, due to the number of parsers involved, it's best to avoid extra spaces in the data URI."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "63445943-ecea-441e-87f5-7d2f361b7c4d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "library_json = json.dumps(\n",
+    "    [dict(shape.items(), xml=deflate(shape[\"xml\"])) for shape in library],\n",
+    "    separators=(\",\", \":\")\n",
+    ")\n",
+    "library_json"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "ad6be53d-0d24-4e5e-99b4-33c9aaf531de",
+   "metadata": {},
+   "source": [
+    "## XML Encoding\n",
+    "\n",
+    "The JSON is wrapped inside an XML document, with a top-level tag of `mxlibrary`."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "82d193a9-2366-4df4-9263-84b65fa96c68",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "library_xml = f\"\"\"<mxlibrary>{library_json}</mxlibrary><!-- /my library -->\"\"\"\n",
+    "library_xml"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "76502de9-f2cb-4485-a438-acb6a06a8ca5",
+   "metadata": {},
+   "source": [
+    "This, in turn, must be transformed into a [Data URI](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs). The whole thing can't be `base64` encoded, because drawio expects a semicolon-separated list of ids. \n",
+    "\n",
+    "> **GOTCHA**: Use of data URIs relies on a **NASTY PATCH** applied when packaging `@deathbeds/jupyterlab-drawio-webpack`: by default, the upstream would rewrite this into a proxied request, which `ipydrawio` don't support. Usually, the name of the library will be derived from the filename, which is usually the last path component after the `/` ... in this case, the _whole document_ is the path, so we make do with some hacks."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "bcd588f0-100e-4dd9-96a7-ea0b16bc6a0f",
+   "metadata": {},
+   "source": [
+    "## URL Encoding"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3f062362-8691-42d9-b9d7-f4a29cf6c405",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "library_data_uri = f\"data:application/xml,{library_xml}\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "c59eeed7-8599-429e-a869-3964b4709964",
+   "metadata": {},
+   "source": []
+  },
+  {
+   "cell_type": "markdown",
+   "id": "ca0d0acc-7186-4f81-83cf-fd93da83f59c",
+   "metadata": {},
+   "source": [
+    "## URL Params\n",
+    "Finally, the most reliable means of communicating with drawio is via its [URL parameters](https://www.diagrams.net/doc/faq/supported-url-parameters), exposed on the widget as `url_params`\n",
+    "\n",
+    "> **GOTCHA** `url_params` should be set before the widget is displayed to avoid extra dialogs. \n",
+    "\n",
+    "The `clibs` parameters accepts a list of \"library keys,\" each with different formats. We are interest in `U` (for `URL`) library.\n",
+    "\n",
+    "> Some others that might be worth exploring some time include `L` for `Local`, which works with an `IndexedDB` instance... but is not guaranteed to be configured by the time a document loads.\n",
+    "\n",
+    "Note, we also override the `stealth` default... `stealth` isn't _strictly_ going to worsen the privacy posture, as all of the other providers are still disabled."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5a89ad37-caf4-4174-90f0-ba51f7c98c3b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "url_params = dict(ipydrawio.Diagram._default_url_params(None))\n",
+    "url_params.update(clibs=f\"U{library_data_uri}\", stealth=\"0\",)\n",
+    "url_params"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "40668d7d-0d2d-4727-add8-ef8d494f0b23",
+   "metadata": {},
+   "source": [
+    "### More URL Params\n",
+    "\n",
+    "A number of other parameters can be useful for custom embedding purposes, such as using a `min`imal `ui`, hiding the default `libs`, disabling additional `p`lugins."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "938af1fe-a2b5-42a0-beee-c93d910b7dfd",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "url_params.update(ui=\"min\", libs=\"0\", p=\"\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "7b7169ce-668f-426c-8146-1c27aa4ef66d",
+   "metadata": {},
+   "source": [
+    "## The Widget"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "91835331-2f68-48af-9ca1-c2512f25ded3",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "d = ipydrawio.Diagram(url_params=url_params, layout=dict(height=\"800px\"))\n",
+    "d"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "bbb0e474-649d-4e33-96c3-5f4f3bad56bd",
+   "metadata": {},
+   "source": [
+    "## Use The Source\n",
+    "\n",
+    "We should now be able to use the desired shapes in the diagram. Unlike `url_params`, the `value` of the diagram's `source` can be updated immediately."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5daa299b-08d8-4ad2-b35e-d599157612e4",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "d.source.value = '''<mxfile version=\"15.8.7\" type=\"embed\">\n",
+    "    <diagram id=\"x\" name=\"My Diagram\">\n",
+    "        <mxGraphModel dx=\"1687\" dy=\"681\" grid=\"1\" gridSize=\"10\" guides=\"1\" tooltips=\"1\" connect=\"1\" arrows=\"1\" fold=\"1\" page=\"1\" pageScale=\"1\" pageWidth=\"850\" pageHeight=\"1100\" math=\"0\" shadow=\"0\"><root><mxCell id=\"0\"/><mxCell id=\"1\" parent=\"0\"/><object label=\"apple\" type=\"Source\" interArrivalTime=\"\" id=\"2\"><mxCell style=\"rhombus;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry x=\"100\" y=\"90\" width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object><object label=\"banana\" type=\"Queue\" capacity=\"\" id=\"3\"><mxCell style=\"ellipse;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry x=\"250\" y=\"90\" width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object><object label=\"cherry\" type=\"Machine\" processingTime=\"\" id=\"4\"><mxCell style=\"whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry x=\"385\" y=\"90\" width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object><object label=\"date\" type=\"Exit\" id=\"5\"><mxCell style=\"rhombus;whiteSpace=wrap;html=1;\" vertex=\"1\" parent=\"1\"><mxGeometry x=\"510\" y=\"90\" width=\"80\" height=\"80\" as=\"geometry\"/></mxCell></object></root>\n",
+    "        </mxGraphModel>\n",
+    "    </diagram>\n",
+    "</mxfile>'''"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/packages/ipydrawio-webpack/drawio b/packages/ipydrawio-webpack/drawio
index bbf17d5f..bdfb2a39 160000
--- a/packages/ipydrawio-webpack/drawio
+++ b/packages/ipydrawio-webpack/drawio
@@ -1 +1 @@
-Subproject commit bbf17d5f5a1d73cb6c955b579cd3691fc55ebae7
+Subproject commit bdfb2a3944aaef1a9f95097a6c30d98fbefce1c4
diff --git a/packages/ipydrawio-webpack/package.json b/packages/ipydrawio-webpack/package.json
index 96680b34..a0940e4d 100644
--- a/packages/ipydrawio-webpack/package.json
+++ b/packages/ipydrawio-webpack/package.json
@@ -43,5 +43,5 @@
     "build:pre": "python scripts/patch.py && python scripts/static.py"
   },
   "types": "lib/index.d.ts",
-  "version": "16.4.0"
+  "version": "16.4.500"
 }
diff --git a/packages/ipydrawio-webpack/scripts/patch.py b/packages/ipydrawio-webpack/scripts/patch.py
index 9677bbec..261fe065 100644
--- a/packages/ipydrawio-webpack/scripts/patch.py
+++ b/packages/ipydrawio-webpack/scripts/patch.py
@@ -29,7 +29,12 @@
             "name": "global ref so we can get at the App at runtime",
             "before": "new App(new Editor",
             "after": "window.IPYDRAWIO_APP = new App(new Editor",
-        }
+        },
+        {
+            "name": "patch cors check for data URI",
+            "before": "this.editor.isCorsEnabledForUrl(n)||(n=",
+            "after": "(n.match(/^data:/) || this.editor.isCorsEnabledForUrl(n))||(n=",
+        },
     ]
 }
 
diff --git a/packages/ipydrawio/package.json b/packages/ipydrawio/package.json
index 9dc8d053..a0fa7350 100644
--- a/packages/ipydrawio/package.json
+++ b/packages/ipydrawio/package.json
@@ -8,7 +8,7 @@
     "@jupyterlab/application": "^3.1.0",
     "@jupyterlab/launcher": "^3.1.0",
     "@jupyterlab/mainmenu": "^3.1.0",
-    "@deathbeds/ipydrawio-webpack": "^16.4.0"
+    "@deathbeds/ipydrawio-webpack": "^16.4.500"
   },
   "description": "A JupyterLab extension for embedding interactive drawio / mxgraph diagrams.",
   "devDependencies": {
diff --git a/yarn.lock b/yarn.lock
index 37e77c09..6dfbeca8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -106,14 +106,14 @@
     "@jupyterlab/application" "^3.1.0"
 
 "@deathbeds/ipydrawio-webpack@file:packages/ipydrawio-webpack":
-  version "16.4.0"
+  version "16.4.500"
   dependencies:
     "@jupyterlab/application" "^3.1.0"
 
 "@deathbeds/ipydrawio@file:packages/ipydrawio":
   version "1.2.0"
   dependencies:
-    "@deathbeds/ipydrawio-webpack" "^16.4.0"
+    "@deathbeds/ipydrawio-webpack" "^16.4.500"
     "@jupyterlab/application" "^3.1.0"
     "@jupyterlab/launcher" "^3.1.0"
     "@jupyterlab/mainmenu" "^3.1.0"