HTML to PDF API Guide: Production Patterns for Stable Output

HTML to PDF works best when layout is deterministic. The goal is to remove rendering surprises across dynamic content lengths and async UI blocks.

1. Start with print-safe HTML/CSS

• Prefer explicit widths and spacing over implicit flow.
• Avoid web fonts that load late unless preloaded.
• Use page-break utilities for long sections/tables.

2. Control viewport

Use stable values like 1080x720 (or your own standard) so wrapping and pagination stay consistent between documents.

3. Choose output mode intentionally

• url for asynchronous workflows and sharing.
• file for direct downloads in user-facing flows.

curl -X POST https://pdfmunk.com/api/v1/generatePdf \
  -H "CLIENT-API-KEY: your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
    "html_content": "<h1>Invoice #INV-1024</h1>",
    "css_content": "h1 { font-size: 24px; }",
    "viewPortWidth": 1080,
    "viewPortHeight": 720,
    "output_format": "url"
  }'

4. Validate template inputs

Sanitize dynamic fields and fallback missing values before rendering. This avoids malformed HTML and layout breaks at runtime.

Conclusion

For reliable HTML to PDF output: standardize viewport, keep print-safe CSS, and validate all template inputs. For implementation details, use our HTML to PDF API page.