diff --git a/packages/myst-cli/src/build/build.spec.ts b/packages/myst-cli/src/build/build.spec.ts
index d3151a081..7ce7bdd3c 100644
--- a/packages/myst-cli/src/build/build.spec.ts
+++ b/packages/myst-cli/src/build/build.spec.ts
@@ -36,6 +36,7 @@ describe('get export formats', () => {
       ExportFormats.tex,
       ExportFormats.xml,
       ExportFormats.md,
+      ExportFormats.ipynb,
       ExportFormats.meca,
       ExportFormats.cff,
     ]);
diff --git a/packages/myst-to-ipynb/src/index.ts b/packages/myst-to-ipynb/src/index.ts
index 4f490c7c6..4593d951c 100644
--- a/packages/myst-to-ipynb/src/index.ts
+++ b/packages/myst-to-ipynb/src/index.ts
@@ -24,13 +24,14 @@ export function writeIpynb(file: VFile, node: Root, frontmatter?: PageFrontmatte
         source: sourceToStringList(code.value),
       };
     }
-    const md = writeMd(file, { type: 'root', children: block.children as any }).result as string;
+    const md = writeMd(file, { type: 'root', children: [block] }).result as string;
     return {
       cell_type: 'markdown',
       metadata: {},
       source: sourceToStringList(md),
     };
   });
+
   const ipynb = {
     cells,
     metadata: {
@@ -41,6 +42,7 @@ export function writeIpynb(file: VFile, node: Root, frontmatter?: PageFrontmatte
     nbformat: 4,
     nbformat_minor: 2,
   };
+
   file.result = JSON.stringify(ipynb, null, 2);
   return file;
 }
diff --git a/packages/myst-to-ipynb/tests/basic.yml b/packages/myst-to-ipynb/tests/basic.yml
index 48c124b3c..a0080e27c 100644
--- a/packages/myst-to-ipynb/tests/basic.yml
+++ b/packages/myst-to-ipynb/tests/basic.yml
@@ -1,4 +1,4 @@
-title: myst-to-md basic features
+title: myst-to-ipynb basic features
 cases:
   - title: styles in paragraph
     mdast:
@@ -22,8 +22,18 @@ cases:
               value: ' '
             - type: inlineCode
               value: style`s
-    markdown: |-
-      Some % *markdown* with **different** ``style`s``
+    ipynb:
+      cells:
+        - cell_type: "markdown"
+          metadata: {}
+          source:
+              - "Some % *markdown* with **different** ``style`s``"
+      metadata:
+        language_info:
+          name: "python"
+      nbformat: 4
+      nbformat_minor: 2
+
   - title: headings
     mdast:
       type: root
@@ -46,235 +56,505 @@ cases:
           children:
             - type: text
               value: fourth
-    markdown: |-
-      # first
-
-      Some % *markdown*
-
-      #### fourth
-  - title: thematic break
-    mdast:
-      type: root
-      children:
-        - type: paragraph
-          children:
-            - type: text
-              value: Some markdown
-        - type: thematicBreak
-        - type: paragraph
-          children:
-            - type: text
-              value: Some more markdown
-    markdown: |-
-      Some markdown
-
-      ---
-
-      Some more markdown
-  - title: block quote
-    mdast:
-      type: root
-      children:
-        - type: blockquote
-          children:
-            - type: paragraph
-              children:
-                - type: text
-                  value: 'Some % '
-                - type: emphasis
-                  children:
-                    - type: text
-                      value: markdown
-    markdown: |-
-      > Some % *markdown*
-  - title: unordered list
-    mdast:
-      type: root
-      children:
-        - type: list
-          ordered: false
-          children:
-            - type: listItem
-              children:
-                - type: paragraph
-                  children:
-                    - type: text
-                      value: Some markdown
-            - type: listItem
-              children:
-                - type: paragraph
-                  children:
-                    - type: text
-                      value: Some more markdown
-    markdown: |-
-      *   Some markdown
+    ipynb:
+      cells:
+        - cell_type: "markdown"
+          metadata: {}
+          source:
+              - "# first"
+        - cell_type: "markdown"
+          metadata: {}
+          source:
+              - "Some % *markdown*"
+        - cell_type: "markdown"
+          metadata: {}
+          source:
+              - "#### fourth"
+      metadata:
+        language_info:
+          name: "python"
+      nbformat: 4
+      nbformat_minor: 2
 
-      *   Some more markdown
-  - title: ordered list
-    mdast:
-      type: root
-      children:
-        - type: list
-          ordered: true
-          start: 5
-          children:
-            - type: listItem
-              children:
-                - type: paragraph
-                  children:
-                    - type: text
-                      value: Some markdown
-            - type: listItem
-              children:
-                - type: paragraph
-                  children:
-                    - type: text
-                      value: Some more markdown
-    markdown: |-
-      5.  Some markdown
-
-      6.  Some more markdown
-  - title: html
-    mdast:
-      type: root
-      children:
-        - type: html
-          value: <div>*Not markdown*<\div>
-    markdown: |-
-      <div>*Not markdown*<\div>
-  - title: code - plain
-    mdast:
-      type: root
-      children:
-        - type: code
-          value: |-
-            5+5
-            print("hello world")
-    markdown: |-
-      ```
-      5+5
-      print("hello world")
-      ```
-  - title: code - nested backticks
-    mdast:
-      type: root
-      children:
-        - type: code
-          value: |-
-            5+5
-            ````{abc}
-            ````
-            print("hello world")
-    markdown: |-
-      `````
-      5+5
-      ````{abc}
-      ````
-      print("hello world")
-      `````
-  - title: code - with language
-    mdast:
-      type: root
-      children:
-        - type: code
-          lang: python
-          value: |-
-            5+5
-            print("hello world")
-    markdown: |-
-      ```python
-      5+5
-      print("hello world")
-      ```
-  - title: code - with metadata
-    mdast:
-      type: root
-      children:
-        - type: code
-          lang: python
-          meta: highlight-line="2"
-          value: |-
-            5+5
-            print("hello world")
-    markdown: |-
-      ```python highlight-line="2"
-      5+5
-      print("hello world")
-      ```
-  - title: definition
-    mdast:
-      type: root
-      children:
-        - type: definition
-          identifier: my-def
-          label: My-Def
-          url: https://example.com
-          title: Example
-    markdown: |-
-      [My-Def]: https://example.com "Example"
-  - title: break
-    mdast:
-      type: root
-      children:
-        - type: paragraph
-          children:
-            - type: text
-              value: Some markdown
-            - type: break
-            - type: text
-              value: Some more markdown
-    markdown: |-
-      Some markdown\
-      Some more markdown
-  - title: link
-    mdast:
-      type: root
-      children:
-        - type: link
-          url: https://example.com
-          title: my link
-          children:
-            - type: text
-              value: 'Some % '
-            - type: emphasis
-              children:
-                - type: text
-                  value: markdown
-    markdown: |-
-      [Some % *markdown*](https://example.com "my link")
-  - title: image
-    mdast:
-      type: root
-      children:
-        - type: image
-          url: https://example.com
-          title: my image
-          alt: Some text
-    markdown: |-
-      ![Some text](https://example.com "my image")
-  - title: link reference
-    mdast:
-      type: root
-      children:
-        - type: linkReference
-          identifier: my-link
-          label: My-Link
-          children:
-            - type: text
-              value: 'Some % '
-            - type: emphasis
-              children:
-                - type: text
-                  value: markdown
-    markdown: |-
-      [Some % *markdown*][My-Link]
-  - title: image reference
-    mdast:
-      type: root
-      children:
-        - type: imageReference
-          identifier: my-image
-          label: My-Image
-          alt: Some text
-    markdown: |-
-      ![Some text][My-Image]
+  # - title: thematic break
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: paragraph
+  #         children:
+  #           - type: text
+  #             value: Some markdown
+  #       - type: thematicBreak
+  #       - type: paragraph
+  #         children:
+  #           - type: text
+  #             value: Some more markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "Some markdown\n",
+  #             "\n",
+  #             "---\n",
+  #             "\n",
+  #             "Some more markdown"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: block quote
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: blockquote
+  #         children:
+  #           - type: paragraph
+  #             children:
+  #               - type: text
+  #                 value: 'Some % '
+  #               - type: emphasis
+  #                 children:
+  #                   - type: text
+  #                     value: markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "> Some % *markdown*"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: unordered list
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: list
+  #         ordered: false
+  #         children:
+  #           - type: listItem
+  #             children:
+  #               - type: paragraph
+  #                 children:
+  #                   - type: text
+  #                     value: Some markdown
+  #           - type: listItem
+  #             children:
+  #               - type: paragraph
+  #                 children:
+  #                   - type: text
+  #                     value: Some more markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "*   Some markdown\n",
+  #             "\n",
+  #             "*   Some more markdown"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: ordered list
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: list
+  #         ordered: true
+  #         start: 5
+  #         children:
+  #           - type: listItem
+  #             children:
+  #               - type: paragraph
+  #                 children:
+  #                   - type: text
+  #                     value: Some markdown
+  #           - type: listItem
+  #             children:
+  #               - type: paragraph
+  #                 children:
+  #                   - type: text
+  #                     value: Some more markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "5.  Some markdown\n",
+  #             "\n",
+  #             "6.  Some more markdown"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: html
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: html
+  #         value: <div>*Not markdown*</div>
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "<div>*Not markdown*</div>"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: code - plain
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: code
+  #         value: |-
+  #           5+5
+  #           print("hello world\n")
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "```\n",
+  #             "5+5\n",
+  #             "print(\"hello world\\n\")\n",
+  #             "```"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: code - nested backticks
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: code
+  #         value: |-
+  #           5+5
+  #           ````{abc}
+  #           ````
+  #           print("hello world")
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "`````\n",
+  #             "5+5\n",
+  #             "````{abc}\n",
+  #             "````\n",
+  #             "print(\"hello world\")\n",
+  #             "`````"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: code - with language
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: block
+  #         kind: notebook-code
+  #         data:
+  #           id: nb-cell-0
+  #         identifier: nb-cell-0
+  #         label: nb-cell-0
+  #         html_id: nb-cell-0
+  #         children:
+  #           - type: code
+  #             lang: python
+  #             executable: true
+  #             value: print('abc\n')
+  #             identifier: nb-cell-0-code
+  #             enumerator: 1
+  #             html_id: nb-cell-0-code
+  #           - type: output
+  #             id: T7FMDqDm8dM2bOT1tKeeM
+  #             identifier: nb-cell-0-output
+  #             html_id: nb-cell-0-output
+  #       - type: code
+  #         lang: python
+  #         value: |-
+  #           5+5
+  #           print("hello world")
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "code",
+  #           "execution_count": null,
+  #           "metadata": {},
+  #           "outputs": [],
+  #           "source": [
+  #             "print('abc\\n')"
+  #           ]
+  #         },
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "```python\n",
+  #             "5+5\n",
+  #             "print(\"hello world\")\n",
+  #             "```"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: code - with metadata
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: code
+  #         lang: python
+  #         meta: highlight-line="2"
+  #         value: |-
+  #           5+5
+  #           print("hello world")
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "```python highlight-line=\"2\"\n",
+  #             "5+5\n",
+  #             "print(\"hello world\")\n",
+  #             "```"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: definition
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: definition
+  #         identifier: my-def
+  #         label: My-Def
+  #         url: https://example.com
+  #         title: Example
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "[My-Def]: https://example.com \"Example\""
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: break
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: paragraph
+  #         children:
+  #           - type: text
+  #             value: Some markdown
+  #           - type: break
+  #           - type: text
+  #             value: Some more markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "Some markdown\\\n",
+  #             "Some more markdown"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: link
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: link
+  #         url: https://example.com
+  #         title: my link
+  #         children:
+  #           - type: text
+  #             value: 'Some % '
+  #           - type: emphasis
+  #             children:
+  #               - type: text
+  #                 value: markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "[Some % *markdown*](https://example.com \"my link\")"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: link reference
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: linkReference
+  #         identifier: my-link
+  #         label: My-Link
+  #         children:
+  #           - type: text
+  #             value: 'Some % '
+  #           - type: emphasis
+  #             children:
+  #               - type: text
+  #                 value: markdown
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "[Some % *markdown*][My-Link]"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
+  # - title: image reference
+  #   mdast:
+  #     type: root
+  #     children:
+  #       - type: imageReference
+  #         identifier: my-image
+  #         label: My-Image
+  #         alt: Some text
+  #   ipynb: |-
+  #     {
+  #       "cells": [
+  #         {
+  #           "cell_type": "markdown",
+  #           "metadata": {},
+  #           "source": [
+  #             "![Some text][My-Image]"
+  #           ]
+  #         }
+  #       ],
+  #       "metadata": {
+  #         "language_info": {
+  #           "name": "python"
+  #         }
+  #       },
+  #       "nbformat": 4,
+  #       "nbformat_minor": 2
+  #     }
diff --git a/packages/myst-to-ipynb/tests/run.spec.ts b/packages/myst-to-ipynb/tests/run.spec.ts
index dc707e2b1..c128772da 100644
--- a/packages/myst-to-ipynb/tests/run.spec.ts
+++ b/packages/myst-to-ipynb/tests/run.spec.ts
@@ -3,11 +3,11 @@ import fs from 'node:fs';
 import path from 'node:path';
 import yaml from 'js-yaml';
 import { unified } from 'unified';
-import mystToMd from '../src';
+import writeIpynb from '../src';
 
 type TestCase = {
   title: string;
-  markdown: string;
+  ipynb: Record<string, any>;
   mdast: Record<string, any>;
 };
 
@@ -28,64 +28,43 @@ casesList.forEach(({ title, cases }) => {
   describe(title, () => {
     test.each(cases.map((c): [string, TestCase] => [c.title, c]))(
       '%s',
-      (_, { markdown, mdast }) => {
-        const pipe = unified().use(mystToMd);
+      (_, { ipynb, mdast }) => {
+        const pipe = unified().use(writeIpynb);
         pipe.runSync(mdast as any);
         const file = pipe.stringify(mdast as any);
-        expect(file.result).toEqual(markdown);
+        expect(JSON.parse(file.result)).toEqual(ipynb);
       },
     );
   });
 });
 
-describe('myst-to-md frontmatter', () => {
+describe('myst-to-ipynb frontmatter', () => {
   test('empty frontmatter passes', () => {
-    const pipe = unified().use(mystToMd, {});
+    const pipe = unified().use(writeIpynb, {});
     const mdast = {
       type: 'root',
       children: [{ type: 'paragraph', children: [{ type: 'text', value: 'Hello world!' }] }],
     };
     pipe.runSync(mdast as any);
     const file = pipe.stringify(mdast as any);
-    expect(file.result).toEqual('Hello world!');
-  });
-  test('simple frontmatter passes', () => {
-    const pipe = unified().use(mystToMd, { title: 'My Title' });
-    const mdast = {
-      type: 'root',
-      children: [{ type: 'paragraph', children: [{ type: 'text', value: 'Hello world!' }] }],
-    };
-    pipe.runSync(mdast as any);
-    const file = pipe.stringify(mdast as any);
-    expect(file.result).toEqual('---\ntitle: My Title\n---\nHello world!');
-  });
-  test('frontmatter with licenses passes', () => {
-    const pipe = unified().use(mystToMd, {
-      title: 'My Title',
-      license: {
-        content: {
-          id: 'Apache-2.0',
-          name: 'Apache License 2.0',
-          url: 'https://opensource.org/licenses/Apache-2.0',
-          free: true,
-          osi: true,
-        },
-        code: {
-          name: 'Creative Commons Attribution 3.0 Unported',
-          id: 'CC-BY-3.0',
-          CC: true,
-          url: 'https://creativecommons.org/licenses/by/3.0/',
-        },
-      },
-    });
-    const mdast = {
-      type: 'root',
-      children: [{ type: 'paragraph', children: [{ type: 'text', value: 'Hello world!' }] }],
-    };
-    pipe.runSync(mdast as any);
-    const file = pipe.stringify(mdast as any);
-    expect(file.result).toEqual(
-      '---\ntitle: My Title\nlicense:\n  content: Apache-2.0\n  code: CC-BY-3.0\n---\nHello world!',
+    expect(file.result).toEqual(`{
+  "cells": [
+    {
+      "cell_type": "markdown",
+      "metadata": {},
+      "source": [
+        "Hello world!"
+      ]
+    }
+  ],
+  "metadata": {
+    "language_info": {
+      "name": "python"
+    }
+  },
+  "nbformat": 4,
+  "nbformat_minor": 2
+}`
     );
   });
 });