Pandoc HTML Pipeline with Diagram Support | A defaults-driven approach to Markdown to HTML with first-class Mermaid rendering

January 2026 9 min read

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<h1 data-number="1" id="the-problem">1 The Problem</h1> Pandoc is powerful but repetitive command usage becomes difficult to maintain. A typical invocation can look like this: <div class="sourceCode" id="cb1"><pre class="sourceCode numberSource bash numberLines"><code class="sourceCode bash"><a href="#cb1-1"></a>pandoc \ <a href="#cb1-2"></a> --standalone \ <a href="#cb1-3"></a> --toc \ <a href="#cb1-4"></a> --number-sections \ <a href="#cb1-5"></a> --filter pandoc/filters/diagram.lua \ <a href="#cb1-6"></a> --highlight-style=pygments \ <a href="#cb1-7"></a> input.md \ <a href="#cb1-8"></a> -o output.html</code></pre></div> When this command is copied across repositories or CI jobs, configuration begins to drift. Teams may add flags in different orders or forget important options. At the same time, introducing a full static site generator felt unnecessary. The requirement was limited to: <ul> <li>Markdown to HTML conversion</li> <li>Proper diagram rendering</li> <li>Consistent syntax highlighting</li> <li>Reproducible output</li> </ul> Pandoc does not support a traditional <code>.rc</code> file, but it does support defaults files. That feature provides a clean and versionable solution. <hr /> <h1 data-number="2" id="architecture-overview">2 Architecture Overview</h1> The architecture is intentionally minimal. <img src="data:image/svg+xml;base64,<svg id="my-svg" width="100%" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" class="flowchart" style="max-width: 276px; background-color: white;" viewBox="0 0 276 430" role="graphics-document document" aria-roledescription="flowchart-v2"><style>#my-svg{font-family:"trebuchet ms",verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#my-svg .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#my-svg .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#my-svg .error-icon{fill:#552222;}#my-svg .error-text{fill:#552222;stroke:#552222;}#my-svg .edge-thickness-normal{stroke-width:1px;}#my-svg .edge-thickness-thick{stroke-width:3.5px;}#my-svg .edge-pattern-solid{stroke-dasharray:0;}#my-svg .edge-thickness-invisible{stroke-width:0;fill:none;}#my-svg .edge-pattern-dashed{stroke-dasharray:3;}#my-svg .edge-pattern-dotted{stroke-dasharray:2;}#my-svg .marker{fill:#333333;stroke:#333333;}#my-svg .marker.cross{stroke:#333333;}#my-svg svg{font-family:"trebuchet ms",verdana,arial,sans-serif;font-size:16px;}#my-svg p{margin:0;}#my-svg .label{font-family:"trebuchet ms",verdana,arial,sans-serif;color:#333;}#my-svg .cluster-label text{fill:#333;}#my-svg .cluster-label span{color:#333;}#my-svg .cluster-label span p{background-color:transparent;}#my-svg .label text,#my-svg span{fill:#333;color:#333;}#my-svg .node rect,#my-svg .node circle,#my-svg .node ellipse,#my-svg .node polygon,#my-svg .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#my-svg .rough-node .label text,#my-svg .node .label text,#my-svg .image-shape .label,#my-svg .icon-shape .label{text-anchor:middle;}#my-svg .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#my-svg .rough-node .label,#my-svg .node .label,#my-svg .image-shape .label,#my-svg .icon-shape .label{text-align:center;}#my-svg .node.clickable{cursor:pointer;}#my-svg .root .anchor path{fill:#333333!important;stroke-width:0;stroke:#333333;}#my-svg .arrowheadPath{fill:#333333;}#my-svg .edgePath .path{stroke:#333333;stroke-width:2.0px;}#my-svg .flowchart-link{stroke:#333333;fill:none;}#my-svg .edgeLabel{background-color:rgba(232,232,232, 0.8);text-align:center;}#my-svg .edgeLabel p{background-color:rgba(232,232,232, 0.8);}#my-svg .edgeLabel rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#my-svg .labelBkg{background-color:rgba(232, 232, 232, 0.5);}#my-svg .cluster rect{fill:#ffffde;stroke:#aaaa33;stroke-width:1px;}#my-svg .cluster text{fill:#333;}#my-svg .cluster span{color:#333;}#my-svg div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:"trebuchet ms",verdana,arial,sans-serif;font-size:12px;background:hsl(80, 100%, 96.2745098039%);border:1px solid #aaaa33;border-radius:2px;pointer-events:none;z-index:100;}#my-svg .flowchartTitleText{text-anchor:middle;font-size:18px;fill:#333;}#my-svg rect.text{fill:none;stroke-width:0;}#my-svg .icon-shape,#my-svg .image-shape{background-color:rgba(232,232,232, 0.8);text-align:center;}#my-svg .icon-shape p,#my-svg .image-shape p{background-color:rgba(232,232,232, 0.8);padding:2px;}#my-svg .icon-shape rect,#my-svg .image-shape rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#my-svg .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#my-svg .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#my-svg :root{--mermaid-font-family:"trebuchet ms",verdana,arial,sans-serif;}</style><g><marker id="my-svg_flowchart-v2-pointEnd" class="marker flowchart-v2" viewBox="0 0 10 10" refX="5" refY="5" markerUnits="userSpaceOnUse" markerWidth="8" markerHeight="8" orient="auto"><path d="M 0 0 L 10 5 L 0 10 z" class="arrowMarkerPath" style="stroke-width: 1; 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stroke-dasharray: 1, 0;"/></marker><marker id="my-svg_flowchart-v2-crossStart" class="marker cross flowchart-v2" viewBox="0 0 11 11" refX="-1" refY="5.2" markerUnits="userSpaceOnUse" markerWidth="11" markerHeight="11" orient="auto"><path d="M 1,1 l 9,9 M 10,1 l -9,9" class="arrowMarkerPath" style="stroke-width: 2; stroke-dasharray: 1, 0;"/></marker><g class="root"><g class="clusters"/><g class="edgePaths"><path d="M138,62L138,66.167C138,70.333,138,78.667,138,86.333C138,94,138,101,138,104.5L138,108" id="L_A_B_0" class="edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link" style=";" data-edge="true" data-et="edge" data-id="L_A_B_0" data-points="W3sieCI6MTM4LCJ5Ijo2Mn0seyJ4IjoxMzgsInkiOjg3fSx7IngiOjEzOCwieSI6MTEyfV0=" marker-end="url(#my-svg_flowchart-v2-pointEnd)"/><path d="M138,190L138,194.167C138,198.333,138,206.667,138,214.333C138,222,138,229,138,232.5L138,236" id="L_B_C_0" class="edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link" style=";" data-edge="true" data-et="edge" data-id="L_B_C_0" data-points="W3sieCI6MTM4LCJ5IjoxOTB9LHsieCI6MTM4LCJ5IjoyMTV9LHsieCI6MTM4LCJ5IjoyNDB9XQ==" marker-end="url(#my-svg_flowchart-v2-pointEnd)"/><path d="M138,318L138,322.167C138,326.333,138,334.667,138,342.333C138,350,138,357,138,360.5L138,364" id="L_C_D_0" class="edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link" style=";" data-edge="true" data-et="edge" data-id="L_C_D_0" data-points="W3sieCI6MTM4LCJ5IjozMTh9LHsieCI6MTM4LCJ5IjozNDN9LHsieCI6MTM4LCJ5IjozNjh9XQ==" marker-end="url(#my-svg_flowchart-v2-pointEnd)"/></g><g class="edgeLabels"><g class="edgeLabel"><g class="label" data-id="L_A_B_0" transform="translate(0, 0)"><foreignObject width="0" height="0"><div xmlns="http://www.w3.org/1999/xhtml" class="labelBkg" style="display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;"><span class="edgeLabel"></span></div></foreignObject></g></g><g class="edgeLabel"><g class="label" data-id="L_B_C_0" transform="translate(0, 0)"><foreignObject width="0" height="0"><div xmlns="http://www.w3.org/1999/xhtml" class="labelBkg" style="display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;"><span class="edgeLabel"></span></div></foreignObject></g></g><g class="edgeLabel"><g class="label" data-id="L_C_D_0" transform="translate(0, 0)"><foreignObject width="0" height="0"><div xmlns="http://www.w3.org/1999/xhtml" class="labelBkg" style="display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;"><span class="edgeLabel"></span></div></foreignObject></g></g></g><g class="nodes"><g class="node default" id="flowchart-A-0" transform="translate(138, 35)"><rect class="basic label-container" style="" x="-60.6875" y="-27" width="121.375" height="54"/><g class="label" style="" transform="translate(-30.6875, -12)"><rect/><foreignObject width="61.375" height="24"><div xmlns="http://www.w3.org/1999/xhtml" style="display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;"><span class="nodeLabel"><p>input.md</p></span></div></foreignObject></g></g><g class="node default" id="flowchart-B-1" transform="translate(138, 151)"><rect class="basic label-container" style="" x="-130" y="-39" width="260" height="78"/><g class="label" style="" transform="translate(-100, -24)"><rect/><foreignObject width="200" height="48"><div xmlns="http://www.w3.org/1999/xhtml" style="display: table; white-space: break-spaces; line-height: 1.5; max-width: 200px; text-align: center; width: 200px;"><span class="nodeLabel"><p>pandoc --defaults pandoc/html.yaml</p></span></div></foreignObject></g></g><g class="node default" id="flowchart-C-3" transform="translate(138, 279)"><rect class="basic label-container" style="" x="-130" y="-39" width="260" height="78"/><g class="label" style="" transform="translate(-100, -24)"><rect/><foreignObject width="200" height="48"><div xmlns="http://www.w3.org/1999/xhtml" style="display: table; white-space: break-spaces; line-height: 1.5; max-width: 200px; text-align: center; width: 200px;"><span class="nodeLabel"><p>diagram.lua filter (mermaid, dot, plantuml)</p></span></div></foreignObject></g></g><g class="node default" id="flowchart-D-5" transform="translate(138, 395)"><rect class="basic label-container" style="" x="-69.578125" y="-27" width="139.15625" height="54"/><g class="label" style="" transform="translate(-39.578125, -12)"><rect/><foreignObject width="79.15625" height="24"><div xmlns="http://www.w3.org/1999/xhtml" style="display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;"><span class="nodeLabel"><p>output.html</p></span></div></foreignObject></g></g></g></g></g></svg>" /> The system consists of: <ul> <li>Pandoc</li> <li>Project-local defaults files</li> <li>A vendored <code>pandoc-ext-diagram</code> Lua filter at <code>pandoc/filters/diagram.lua</code></li> </ul> There are no wrapper scripts or hidden logic. <hr /> <h1 data-number="3" id="what-i-learned">3 What I Learned</h1> <h2 data-number="3.1" id="defaults-files-scale-better-than-aliases">3.1 Defaults Files Scale Better Than Aliases</h2> The core of the project is a small set of defaults files: <div class="sourceCode" id="cb2"><pre class="sourceCode numberSource yaml numberLines"><code class="sourceCode yaml"><a href="#cb2-1"></a># pandoc/html.yaml <a href="#cb2-2"></a> <a href="#cb2-3"></a>from: markdown+fenced_code_blocks+pipe_tables+task_lists <a href="#cb2-4"></a>to: html5 <a href="#cb2-5"></a> <a href="#cb2-6"></a>standalone: true <a href="#cb2-7"></a>embed-resources: true <a href="#cb2-8"></a> <a href="#cb2-9"></a>filters: <a href="#cb2-10"></a> - pandoc/filters/diagram.lua <a href="#cb2-11"></a> <a href="#cb2-12"></a>metadata: <a href="#cb2-13"></a> diagram: <a href="#cb2-14"></a> cache: true <a href="#cb2-15"></a> <a href="#cb2-16"></a>highlight-style: pygments <a href="#cb2-17"></a> <a href="#cb2-18"></a>toc: true <a href="#cb2-19"></a>toc-depth: 3 <a href="#cb2-20"></a>number-sections: true <a href="#cb2-21"></a> <a href="#cb2-22"></a>html-q-tags: true <a href="#cb2-23"></a>wrap: none</code></pre></div> Key observations: <ul> <li>Defaults files are version-controlled.</li> <li>Configuration is explicit and shared across environments.</li> <li>CLI overrides remain possible.</li> </ul> For example: <div class="sourceCode" id="cb3"><pre class="sourceCode numberSource bash numberLines"><code class="sourceCode bash"><a href="#cb3-1"></a>pandoc \ <a href="#cb3-2"></a> --defaults pandoc/html.yaml \ <a href="#cb3-3"></a> --toc-depth=2 \ <a href="#cb3-4"></a> input.md \ <a href="#cb3-5"></a> -o output.html</code></pre></div> This structure reduces duplication while preserving flexibility. <hr /> <h2 data-number="3.2" id="pandoc-ext-diagram-integrates-cleanly">3.2 <code>pandoc-ext-diagram</code> Integrates Cleanly</h2> Mermaid content in Markdown: <div class="sourceCode" id="cb4"><pre class="sourceCode markdown"><code class="sourceCode markdown"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a>```mermaid {.numberLines} <a href="#cb4-2" aria-hidden="true" tabindex="-1"></a>sequenceDiagram <a href="#cb4-3" aria-hidden="true" tabindex="-1"></a> Alice->>Bob: Hello <a href="#cb4-4" aria-hidden="true" tabindex="-1"></a> Bob-->>Alice: Hi <a href="#cb4-5" aria-hidden="true" tabindex="-1"></a>```</code></pre></div> The filter configuration: <div class="sourceCode" id="cb5"><pre class="sourceCode numberSource yaml numberLines"><code class="sourceCode yaml"><a href="#cb5-1"></a>filters: <a href="#cb5-2"></a> - pandoc/filters/diagram.lua</code></pre></div> The filter intercepts supported diagram languages and renders them appropriately. Non-diagram code blocks are processed by Pandoc’s built-in syntax highlighter: <div class="sourceCode" id="cb6"><pre class="sourceCode markdown"><code class="sourceCode markdown"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>```python {.numberLines} <a href="#cb6-2" aria-hidden="true" tabindex="-1"></a>def hello(): <a href="#cb6-3" aria-hidden="true" tabindex="-1"></a> print("hi") <a href="#cb6-4" aria-hidden="true" tabindex="-1"></a>```</code></pre></div> Enabling caching is important for performance: <div class="sourceCode" id="cb7"><pre class="sourceCode numberSource yaml numberLines"><code class="sourceCode yaml"><a href="#cb7-1"></a>metadata: <a href="#cb7-2"></a> diagram: <a href="#cb7-3"></a> cache: true</code></pre></div> Without caching, rebuild times increase significantly when diagrams are present. <hr /> <h2 data-number="3.3" id="standalone-true-is-important">3.3 <code>standalone: true</code> Is Important</h2> <div class="sourceCode" id="cb8"><pre class="sourceCode numberSource yaml numberLines"><code class="sourceCode yaml"><a href="#cb8-1"></a>standalone: true</code></pre></div> Without this option: <ul> <li>The output is not a complete HTML document.</li> <li>Metadata handling can be inconsistent.</li> <li>Integration with preview tools becomes less predictable.</li> </ul> Using standalone mode ensures a full HTML document with proper structure. <hr /> <h2 data-number="3.4" id="explicit-markdown-extensions-prevent-inconsistencies">3.4 Explicit Markdown Extensions Prevent Inconsistencies</h2> <div class="sourceCode" id="cb9"><pre class="sourceCode numberSource yaml numberLines"><code class="sourceCode yaml"><a href="#cb9-1"></a>from: markdown+fenced_code_blocks+pipe_tables+task_lists</code></pre></div> Explicitly defining extensions avoids version-dependent behavior changes. It ensures consistent parsing across environments and CI systems. Relying on implicit defaults can lead to subtle formatting differences when Pandoc versions change. <hr /> <h2 data-number="3.5" id="avoid-expanding-scope-prematurely">3.5 Avoid Expanding Scope Prematurely</h2> This project intentionally excludes: <ul> <li>Custom HTML templates</li> <li>Static asset pipelines</li> <li>Wrapper scripts</li> <li>JavaScript integrations</li> </ul> The responsibility of this configuration is limited to Markdown to HTML conversion with diagram support. A reusable syntax highlighting stylesheet is provided at <code>pandoc/syntax-highlighting.css</code>, but styling decisions are intentionally minimal. Additional features can be layered separately if required. <hr /> <h1 data-number="4" id="using-it">4 Using It</h1> A typical invocation: <div class="sourceCode" id="cb10"><pre class="sourceCode numberSource bash numberLines"><code class="sourceCode bash"><a href="#cb10-1"></a>pandoc \ <a href="#cb10-2"></a> --defaults pandoc/html.yaml \ <a href="#cb10-3"></a> input.md \ <a href="#cb10-4"></a> -o output.html</code></pre></div> The defaults file centralizes shared configuration while keeping input and output explicit. To introduce additional output types, create new defaults files: <div class="sourceCode" id="cb11"><pre class="sourceCode numberSource numberLines"><code class="sourceCode"><a href="#cb11-1"></a>pandoc/pdf.yaml <a href="#cb11-2"></a>pandoc/slides.yaml</code></pre></div> Each configuration remains isolated and independently maintainable. <hr /> <h1 data-number="5" id="whats-next">5 What’s Next</h1> Potential extensions include: <ul> <li>A PDF defaults configuration using a LaTeX engine</li> <li>Custom HTML templates</li> <li>Diagram backend customization</li> <li>Version pinning Pandoc in CI</li> <li>Integrating into a broader publishing workflow</li> </ul> These can be added without changing the existing HTML configuration. <hr /> The full project, including the defaults configuration and setup instructions, is available here: GitHub: <a href="https://github.com/nanacnote/md2html-pipeline">https://github.com/nanacnote/md2html-pipeline</a>

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