pdf export using webpdf fails

[vascotenner]

Describe the bug

When trying to export to PDF it gives the following error. How to solve? How to even debug?

> marimo export pdf .\test.py -o out.pdf
Exporting PDF: executing notebook...
Exporting PDF: notebook execution finished.
Exporting PDF: serializing notebook for PDF rendering...
Exporting PDF: rendering PDF via WebPDF...
Task exception was never retrieved
future: <Task finished name='Task-4' coro=<Connection.run() done, defined at C:\Users\user\.virtualenvs\marimo\Lib\site-packages\playwright\_impl\_connection.py:305> exception=NotImplementedError()>
Traceback (most recent call last):
  File "C:\Users\user\.virtualenvs\marimo\Lib\site-packages\playwright\_impl\_connection.py", line 312, in run
    await self._transport.connect()
  File "C:\Users\user\.virtualenvs\marimo\Lib\site-packages\playwright\_impl\_transport.py", line 133, in connect
    raise exc
  File "C:\Users\user\.virtualenvs\marimo\Lib\site-packages\playwright\_impl\_transport.py", line 120, in connect
    self._proc = await asyncio.create_subprocess_exec(
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<9 lines>...
    )
    ^
  File "C:\Users\user\AppData\Local\Programs\Python\Python314\Lib\asyncio\subprocess.py", line 224, in create_subprocess_exec
    transport, protocol = await loop.subprocess_exec(
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
        stderr=stderr, **kwds)
        ^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\user\AppData\Local\Programs\Python\Python314\Lib\asyncio\base_events.py", line 1798, in subprocess_exec
    transport = await self._make_subprocess_transport(
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        protocol, popen_args, False, stdin, stdout, stderr,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        bufsize, **kwargs)
        ^^^^^^^^^^^^^^^^^^
  File "C:\Users\user\AppData\Local\Programs\Python\Python314\Lib\asyncio\base_events.py", line 533, in _make_subprocess_transport
    raise NotImplementedError
NotImplementedError
Error: Failed to export PDF:

Will you submit a PR?

• Yes

Environment

Details

{
  "marimo": "0.23.8",
  "editable": false,
  "location": "C:/Users/user/.virtualenvs/marimo/Lib/site-packages/marimo",
  "OS": "Windows",
  "OS Version": "11",
  "Processor": "Intel64 Family 6 Model 186 Stepping 2, GenuineIntel",
  "Python Version": "3.14.0",
  "Locale": "--",
  "Binaries": {
    "Browser": "--",
    "Node": "--",
    "uv": "--"
  },
  "Dependencies": {
    "click": "8.3.1",
    "docutils": "0.22.4",
    "itsdangerous": "2.2.0",
    "jedi": "0.19.2",
    "markdown": "3.10.2",
    "narwhals": "2.18.1",
    "packaging": "26.0",
    "psutil": "7.2.2",
    "pygments": "2.20.0",
    "pymdown-extensions": "10.21.2",
    "pyyaml": "6.0.3",
    "starlette": "1.0.0",
    "tomlkit": "0.14.0",
    "typing-extensions": "4.15.0",
    "uvicorn": "0.42.0",
    "websockets": "16.0"
  },
  "Optional Dependencies": {
    "altair": "6.1.0",
    "anywidget": "0.11.0",
    "loro": "1.10.3",
    "nbformat": "5.10.4",
    "pandas": "3.0.3",
    "polars": "1.39.3",
    "pytest": "9.0.3",
    "ruff": "0.15.10"
  },
  "Experimental Flags": {}
}

Code to reproduce

No response

[akshayka]

Hi @vascotenner, thank you for reporting. It looks like this is an incompatibility with our PDF export on Windows.

We will look into fixing this.

In the meantime, here are some workarounds:

1. Can you try: marimo export pdf --no-webpdf .\test.py -o out.pdf? This will require you to install Pandoc/LaTeX, but may be more reliable.
2. If (1) is not a possibility, can you try to use Python 3.13 instead of 3.14?

[akshayka]

I believe a fix would be along the lines of #9194

[akshayka]

Here is the upstream issue: jupyter/nbconvert#2287

[Yasin197]

I've seen this error message too in the past