nb2wb 0.1.2

Write in Jupyter Notebooks. Publish anywhere.

nb2wb

Write in notebooks. Publish anywhere.

nb2wb converts:

• Jupyter notebooks (.ipynb)
• Quarto documents (.qmd)
• Markdown files (.md)

into platform-ready HTML for:

• Substack
• Medium
• X Articles

The output is designed for copy/paste workflows where platforms often break MathJax and code formatting.

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Why nb2wb

Most publishing editors strip or mangle:

• LaTeX
• code blocks
• notebook outputs

nb2wb preserves fidelity by rendering complex parts as images and converting inline math to Unicode.

Content type	Converted as
Inline math $...$	Unicode + light HTML formatting
Display math ($$...$$, \[...\], \begin{...})	PNG
Code input	Syntax-highlighted PNG (or copyable text snippet)
Text outputs / errors	PNG
image/png outputs	Embedded as image data URI
image/svg+xml outputs	Sanitized SVG as image data URI
text/html outputs	Sanitized HTML fragment

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Feature Overview

• Converts .ipynb, .qmd, and .md from one CLI.
• Platform-specific page wrappers for Substack, Medium, and X.
• One-click copy toolbar in generated HTML.
• Medium/X per-image copy buttons for reliable image transfer.
• Optional --serve mode (local server + ngrok URL).
• Equation labels and cross-references:
  • \label{...} in display math
  • \eqref{...} replaced with (N)
• LaTeX rendering strategy:
  • tries full latex + dvipng
  • falls back to matplotlib mathtext
• Inline LaTeX conversion pipeline:
  • unicode command replacement
  • superscript/subscript expansion
  • variable italicization
• Code rendering controls:
  • Pygments theme
  • line numbers
  • font size
  • padding / border radius
• Cell-level visibility and behavior tags:
  • hide-cell, hide-input, hide-output, latex-preamble, text-snippet
• Markdown directives in .md via <!-- nb2wb: ... -->.
• Quarto #| options mapped to notebook-style tags.
• Security hardening for image fetching and HTML/SVG embedding.

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Installation

pip install nb2wb

Development install:

git clone https://github.com/the-palindrome/nb2wb.git
cd nb2wb
pip install -e ".[dev]"

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Quick Start

nb2wb notebook.ipynb
nb2wb notebook.ipynb -t medium
nb2wb notebook.ipynb -t x
nb2wb notebook.ipynb -o article.html
nb2wb notebook.ipynb --open
nb2wb notebook.ipynb --serve
nb2wb article.md
nb2wb article.md --execute
nb2wb report.qmd

Default output path is <input_basename>.html.

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CLI Reference

nb2wb <input.{ipynb|qmd|md}> [options]

Option	Meaning
-t, --target {substack,medium,x}	Target platform (substack default)
-c, --config PATH	YAML config file
-o, --output PATH	Output HTML path
--open	Open generated HTML in browser
--serve	Extract images, start local server, expose via ngrok
--execute	Execute code cells for .md files (ignored for .qmd, which are always executed)

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Platform Behavior

Platform	Paste workflow	Image behavior
Substack	One-click copy/paste	Embedded images transfer directly
Medium	Copy/paste + optional per-image copy	Base64 images may be stripped by editor
X Articles	Copy/paste + optional per-image copy	Base64 images may be stripped by editor

--serve mode

--serve helps Medium/X workflows by replacing embedded data URIs with public HTTP URLs.

What it does:

1. Extracts supported image MIME types from the generated HTML into images/
2. Rewrites <img src="..."> to those files
3. Starts local HTTP server
4. Starts ngrok tunnel and opens the public URL

Requirements:

• ngrok installed
• ngrok authenticated (ngrok config add-authtoken <TOKEN>)

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Input Format Support

.ipynb

• Uses notebook cells and outputs directly.
• Supports notebook tags in cell.metadata.tags.
• Uses notebook/kernel metadata to infer language for syntax highlighting.

.md

Supported features:

• Optional YAML front matter
• Fenced code blocks with backticks or tildes
• Per-fence tags (```python hide-input style)
• Directive comments:
  • <!-- nb2wb: hide-input -->
  • <!-- nb2wb: hide-output -->
  • <!-- nb2wb: hide-cell -->
  • <!-- nb2wb: text-snippet -->
  • comma-separated combinations are supported
• Special fence language:
  • latex-preamble

Execution:

• Not executed by default
• Executed when --execute is provided

.qmd

Supported features:

• Optional YAML front matter
• Quarto fenced chunks (```{python} etc.)
• Quarto options mapped to tags:
  • #| echo: false -> hide-input
  • #| output: false -> hide-output
  • #| include: false or #| eval: false -> hide-cell
  • #| tags: [tag1, tag2] -> tags
• Special chunk languages:
  • latex-preamble
  • output (attaches stdout to the immediately preceding code cell)

Execution:

• .qmd code execution is always attempted by design

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Cell Tags

Tag	Effect
hide-cell	Hide entire cell (input + output)
hide-input	Hide code input
hide-output	Hide outputs
latex-preamble	Use cell/chunk content as LaTeX preamble and hide it
text-snippet	Render code as <pre><code> instead of PNG

hide-cell applies to markdown cells too.

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LaTeX Features

Display math

Detected forms include:

• $$...$$
• \[...\]
• \begin{equation}...\end{equation}
• \begin{align}...\end{align}
• \begin{gather}...\end{gather}
• \begin{multline}...\end{multline}
• \begin{eqnarray}...\end{eqnarray}
• starred variants where applicable

Equation numbering and references

• \label{eq:name} assigns equation number
• \eqref{eq:name} is replaced with (N) across the document

Inline math

Inline $...$ expressions are converted to Unicode-oriented text with script handling.

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LaTeX Preamble Sources

All of these are combined:

1. Config (latex.preamble)
2. Notebook markdown cells tagged latex-preamble
3. .md fenced blocks labeled latex-preamble
4. .qmd chunks {latex-preamble}

Note:

• preamble only affects full LaTeX (try_usetex: true path)
• matplotlib mathtext fallback ignores custom preamble

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Output Rendering Details

For code cells:

• Source code -> syntax-highlighted PNG
• Footer includes execution count and language label
• Text output / tracebacks -> muted output PNG block

Rich outputs:

• image/png -> embedded directly
• image/svg+xml -> sanitized and embedded as data:image/svg+xml;base64,...
• text/html -> sanitized HTML fragment

Raw notebook cells are skipped.

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Configuration

Pass with:

nb2wb notebook.ipynb -c config.yaml

Complete config schema (with defaults)

# Global defaults
image_width: 1920
border_radius: 14

code:
  font_size: 48
  theme: "monokai"
  line_numbers: true
  font: "DejaVu Sans Mono"
  image_width: 1920
  padding_x: 100
  padding_y: 100
  separator: 0
  background: ""       # empty = use theme background
  border_radius: 14

latex:
  font_size: 48
  dpi: 150
  color: "black"
  background: "white"
  padding: 68          # pixels
  image_width: 1920
  try_usetex: true
  preamble: ""
  border_radius: 0

Inheritance behavior:

• code.image_width and latex.image_width inherit top-level image_width unless overridden
• code.border_radius and latex.border_radius inherit top-level border_radius unless overridden

Platform defaults applied automatically

When target is medium or x, defaults are adjusted for narrower layouts:

• top-level image_width: 680
• code.font_size: 42
• code.image_width: 1200
• code.padding_x: 30
• code.padding_y: 30
• code.separator: 0
• latex.font_size: 35
• latex.padding: 50
• latex.image_width: 1200

Substack keeps base defaults unless your config overrides them.

Code themes

Any Pygments style works. Example:

python -c "from pygments.styles import get_all_styles; print(sorted(get_all_styles()))"

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Security Model

nb2wb includes guardrails for image ingestion and HTML embedding:

Image URL/file safety

• Only http / https remote image URLs are allowed
• Requests to private/loopback hosts are blocked (SSRF protection)
• Redirect targets are re-validated (no public-to-private redirect bypass)
• Download timeout and max size checks are enforced
• MIME type allowlist is enforced for fetched/read images
• Local image paths:
  • absolute paths rejected
  • .. traversal rejected
  • symlink escape outside current working directory rejected

Embedded content sanitization

• Markdown-generated HTML is sanitized before embedding
• text/html outputs are sanitized
• SVG outputs are sanitized, then embedded via image data URI
• Dangerous tags/attributes/URI schemes are stripped or neutralized

Important:

• Notebook execution (.qmd or --execute) runs code. Treat untrusted notebooks as untrusted code.
• Sanitization is best-effort, not a browser sandbox.

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Requirements

Core dependencies:

• Python >=3.9
• nbformat
• nbconvert
• ipykernel
• matplotlib
• Pillow
• Pygments
• PyYAML
• markdown
• unicodeit

Optional system tools:

• LaTeX + dvipng (for highest-fidelity display math rendering)
• ngrok (for --serve)

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Development

Run tests:

pytest
pytest tests/unit/
pytest tests/integration/
pytest tests/workflow/

Format:

black nb2wb tests
isort nb2wb tests

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Limitations

• Platforms can change paste behavior without notice.
• Medium/X may still require per-image copy depending editor behavior.
• Extremely complex custom HTML can be altered by sanitization.
• .qmd execution requires a working Jupyter kernel setup.

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License

MIT