Beautiful Diagrams

Generate professional article diagrams using HTML + Playwright screenshots.

Style: bold white carousel. White background, thick black borders (3-4px), chunky rounded cards with 6px drop shadows, terracotta (#E27D5B) icon tiles, Inter 900 typography at large sizes. Designed to be readable in-feed on LinkedIn / Substack, not a reader-hostile monitoring UI.

Design tokens:

Typography: Inter (400–900 weights), loaded from Google Fonts. Headings use weight 900 at 24-28px. Body text is 14-18px. Connector labels and badges are uppercase bold at 11-14px on accent pills. Nothing smaller than 13px.

Rules:

1. NEVER use small fonts. If content doesn't fit, increase the canvas width or drop the fixed height — don't shrink the text.
2. Thick borders (3-4px) on everything. No hairlines.
3. Cards have a 6-7px solid black offset shadow (no blur, no gradients).
4. Icon tiles are rounded squares (14px radius) with 4px black borders and terracotta fill.
5. Connector labels are small uppercase pills on terracotta with black borders.
6. Use the color field to override an individual card/node's accent. Default is terracotta.

Requirements

pip install playwright
python -m playwright install chromium

Quick Start

python scripts/diagram-generator.py --config diagram.json -o diagram.png

Diagram Types

Icons (IBM Carbon Design System)

The icon field in JSON configs supports IBM Carbon icon names (preferred) or emoji fallback. Use Carbon icon names for a professional, monoline look.

Available Carbon icons:

Usage: Set "icon": "branch" instead of "icon": "🔀". Emoji still works as fallback.

1. Pipeline (Architecture / Flow)

Horizontal flow of service cards connected by arrows. Great for system architecture, CI/CD pipelines, data flows.

{
  "type": "pipeline",
  "width": 900,
  "height": 627,
  "nodes": [
    {
      "name": "Developer",
      "desc": "/deploy prod",
      "icon": "👨‍💻",
      "color": "linkedin",
      "trigger": true,
      "child": {
        "name": "Slack",
        "desc": "Slash Command",
        "icon": "💬",
        "color": "slack",
        "width": 130
      }
    },
    {
      "name": "GitHub",
      "desc": "CI/CD",
      "icon": "⚙️",
      "color": "github",
      "components": [
        {"name": "Actions", "desc": "Run tests & build", "icon": "🔄", "tag": "CI"},
        {"name": "Deploy", "desc": "Push to production", "icon": "🚀", "tag": "CD"}
      ]
    },
    {
      "name": "AWS",
      "desc": "Hosting",
      "icon": "☁️",
      "color": "aws"
    }
  ],
  "connectors": [
    {"label": "git push"},
    {"label": "deploy"}
  ]
}

Node options:

• name - Service name (required)
• desc - Short description (optional)
• icon - Emoji icon (optional)
• color - Color preset or hex (see Colors below)
• trigger - If true, renders as a top trigger box with vertical arrow down
• child - When trigger is true, a service card rendered below the trigger (has name, desc, icon, color, width)
• width - Override card width in px (default 130)
• components - Sub-items inside the card (each has name, desc, icon, tag)

Connector options:

• label - Text on the arrow (optional)
• bidirectional - Two-way arrow (default false)
• forwardlabel / reverselabel - Labels for bidirectional arrows

2. Sequence

Sequence diagram with actors, lifelines, phase labels, messages, and notes. Great for API flows, request/response chains, workflow steps.

{
  "type": "sequence",
  "width": 890,
  "actors": [
    {"name": "Client", "color": "linkedin"},
    {"name": "API Gateway", "color": "cloudflare"},
    {"name": "Auth Service", "color": "teal"},
    {"name": "Database", "color": "postgres"}
  ],
  "steps": [
    {"type": "phase", "label": "Authentication"},
    {"type": "message", "from": 0, "to": 1, "label": "POST /login", "style": "solid"},
    {"type": "message", "from": 1, "to": 2, "label": "validate token", "style": "solid"},
    {"type": "message", "from": 2, "to": 1, "label": "200 OK", "style": "dashed"},
    {"type": "spacer"},
    {"type": "phase", "label": "Data Fetch"},
    {"type": "message", "from": 1, "to": 3, "label": "SELECT * FROM users", "style": "solid"},
    {"type": "note", "over": 3, "text": "Query executes<br>Index scan on email"}
  ]
}

Step types:

• message - Arrow between two actors: from (index), to (index), label, style ("solid" | "dashed")
• self - Self-referencing note on an actor: actor (index), label
• note - Highlighted note box: over (actor index), text (supports <br>)
• phase - Section label in teal: label
• spacer - Vertical spacing

3. Grid (Tokens / Secrets / Config Map)

Card grid with items inside each card, plus optional connection arrows. Great for secrets/tokens maps, config overviews, feature comparisons.

{
  "type": "grid",
  "width": 800,
  "columns": 2,
  "cards": [
    {
      "name": "Environment Variables",
      "icon": "🔧",
      "color": "github",
      "items": [
        {"name": "DATABASE_URL", "hint": "PostgreSQL connection string"},
        {"name": "REDIS_URL", "hint": "Redis cache endpoint"},
        {"name": "DEBUG", "hint": "Set to false in production", "badge": "optional"}
      ]
    },
    {
      "name": "API Keys",
      "icon": "🔑",
      "color": "cobalt",
      "items": [
        {"name": "OPENAI_API_KEY", "hint": "From platform.openai.com"},
        {"name": "STRIPE_SECRET", "hint": "Dashboard → Developers → API keys"}
      ]
    }
  ],
  "connections": [
    {"from": "DATABASE_URL", "to": "PostgreSQL"},
    {"from": "REDIS_URL", "to": "Redis", "dashed": true}
  ]
}

Card options:

• name - Card title (required)
• icon - Emoji icon (optional)
• color - Color preset or hex
• items - List of items, each with name, hint (optional), badge (optional)

Connection options:

• from / to - Label text on each side of the arrow
• dashed - Dashed line style (default false)

4. Stack (Numbered Hero Cards)

Vertical stack of big numbered cards. Perfect for "3 lessons", "5 principles", "N reasons why" articles — each item gets full-width treatment with a large 72px number, icon tile, bold title, and descriptive subtitle.

{
  "type": "stack",
  "width": 1200,
  "title": "Optional heading above the stack",
  "items": [
    {
      "number": "01",
      "icon": "close",
      "color": "terracotta",
      "name": "Item title",
      "desc": "Longer explanation that wraps to multiple lines if needed."
    },
    {
      "icon": "activity",
      "color": "teal",
      "name": "Second item",
      "desc": "number is auto-generated when omitted"
    }
  ]
}

Item options:

• number - Display number (optional, auto-generated as "01", "02", ... if omitted)
• icon - Carbon icon name or emoji (optional)
• color - Accent color for the icon tile (optional, default terracotta)
• name - Item title, required
• desc - Longer description (optional)

Sizing tip: use width: 1200 and omit height — stack auto-sizes to content. For 3-item stacks expect ~700px height, for 5-item ~1100px.

5. Comparison (Before / After, A vs B)

Two-column head-to-head comparison with a divider pill in the middle. Use for before/after migrations, naive vs optimized approaches, old vs new workflows.

{
  "type": "comparison",
  "width": 1200,
  "title": "Optional heading",
  "divider": "VS",
  "left": {
    "name": "Before",
    "icon": "close",
    "color": "github",
    "items": [
      "Simple string item",
      {"name": "Item with hint", "hint": "Longer explanation under the name"}
    ]
  },
  "right": {
    "name": "After",
    "icon": "checkmark",
    "color": "teal",
    "items": [
      "Better approach",
      {"name": "With context", "hint": "why it's better"}
    ]
  }
}

Column options:

• name - Column header title, required
• icon - Carbon icon name or emoji (optional)
• color - Accent color for the icon tile (optional, default terracotta)
• items - List of strings OR {name, hint} objects

Top-level options:

• title - Heading above the comparison (optional)
• divider - Text shown in the center pill (default "VS"). Use "→", "THEN", "NOW", etc.

Color Presets

Use these preset names in the color field:

You can also use raw hex colors: "#FF5733". Legacy two-item lists ["#FF5733", "#C70039"] are still accepted (first value wins).

Default: If color is omitted, the card uses terracotta (#E27D5B). The color fills the icon tile; card borders and text are always solid black.

CLI Options

python scripts/diagram-generator.py [options]

Animated GIF Output

For diagrams with CSS animations (flowing particles, pulse effects, fade-ins), use --gif to capture as an animated GIF. Also saves a static PNG of the final frame automatically.

Requirements: ffmpeg (brew install ffmpeg)

CLI usage:

python scripts/diagram-generator.py --config diagram.json --gif -o diagram.gif
python scripts/diagram-generator.py --config diagram.json --gif --gif-duration 6000 --gif-fps 12 -o diagram.gif

JSON config:

{
  "type": "pipeline",
  "animated": true,
  "gif_duration": 5500,
  "gif_fps": 10,
  "width": 1200,
  "height": 627,
  "nodes": [...]
}

Setting "animated": true in the config has the same effect as --gif. The generator captures frames at the specified FPS for the duration, then assembles them into a GIF with ffmpeg.

Output files:

• diagram.gif - Animated GIF
• diagram_static.png - Static final frame (useful for Substack covers which don't support GIF)

Tips:

• Add CSS @keyframes animations to your HTML for flowing particles, pulse rings, fade-ins
• 10fps at 5.5 seconds (55 frames) keeps GIF size under 200KB
• Use height in config (required for GIF mode)

Workflow

1. Determine diagram type from user's description: pipeline (flow/architecture), sequence (interactions/steps), or grid (config/tokens/comparison)
2. Build the JSON config with nodes, actors, or cards as appropriate
3. Save the JSON to the article's files/ folder (e.g., diagram_architecture.json)
4. Run the generator to create the PNG
5. Optionally save HTML with --save-html for future editing

Examples

Architecture diagram for an article:

python scripts/diagram-generator.py \
  --config posts/daily-thoughts/09-fix-my-bug/files/diagram_architecture.json \
  --save-html posts/daily-thoughts/09-fix-my-bug/files/diagram_architecture.html \
  -o posts/daily-thoughts/09-fix-my-bug/files/diagram_architecture.png

Quick diagram from inline JSON:

echo '{"type":"pipeline","nodes":[{"name":"A","icon":"📦","color":"github"},{"name":"B","icon":"🚀","color":"teal"}],"connectors":[{"label":"deploy"}]}' | \
  python scripts/diagram-generator.py --stdin -o quick-diagram.png

Sizing (IMPORTANT)

The bold style uses large typography and chunky cards, so the default canvas should be WIDER than the old dark-minimal style. Recommended starting points:

• Pipeline (horizontal flow): "width": 1400-1600, "height": 520-600. For 4+ nodes prefer 1500+.
• Grid (2 columns × 2 rows): "width": 1200, OMIT height (let it auto-size to content).
• Grid (2 × 3+ rows): "width": 1200, omit height.
• Sequence: "width": 1200-1400, omit height for short flows, set 800-1000 for long ones.
• Stack (numbered cards): "width": 1200, omit height. 3-item stacks land ~700px, 5-item ~1100px.
• Comparison (two columns): "width": 1200-1400, omit height. Each column should hold 3-5 items for best balance.

Rule of thumb: if content looks cramped, INCREASE the width. Do NOT shrink the font sizes — they are deliberately large so the diagrams are readable in-feed on LinkedIn and Substack.

When to set height:

• Fixed aspect ratio for a cover image (e.g., 1200×627 for LinkedIn landscape).
• GIF mode — height is required.
• Otherwise omit it and let the content define the height.

Tips

• Increase canvas width before shrinking content. Small fonts are a regression.
• Keep node/actor names short (1-3 words) — the bold weight eats horizontal space fast.
• Use components in pipeline nodes to show sub-services within a larger card.
• Use phase steps in sequence diagrams to label sections (renders as an accent pill).
• Grid diagrams with connections work best with 2 columns.
• --save-html saves the generated HTML for manual tweaks in a browser.
• Use trigger: true on the first pipeline node for user-initiated flows.

Cost

Free! No API costs. Runs locally with Playwright.