HTML to PDF API

POST /html2pdf

Send HTML, get a PDF. The whole document is rendered in a real Chromium instance, so your CSS, layout, and fonts come out exactly as in the browser.

Request body

Example. Simple HTML

curl -X POST https://e.customjs.io/html2pdf \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -d '{
    "input": {
      "html": "<h1>Hello World</h1>"
    }
  }' \
  > output.pdf

Templating with Nunjucks

Store the design once and send only your data. Add a data object and reference it in the HTML with {{ variable }} placeholders. Perfect for invoices, reports, and certificates.

curl -X POST https://e.customjs.io/html2pdf \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -d '{
    "input": {
      "html": "<h1>Hello {{ name }}</h1><p>Total: {{ total }}</p>",
      "data": { "name": "John", "total": 100 },
      "config": { "pdfWidthMm": 150, "pdfHeightMm": 150 }
    }
  }' \
  > output.pdf

Advanced rendering

Because conversion runs in a real Chromium instance, your template can execute JavaScript. Load external libraries, draw charts, or generate QR codes at render time.

External JavaScript libraries (QR codes)

Import ES modules straight from a CDN inside a <script type="module"> tag.

<script type="module">
  import QRCode from 'https://cdn.jsdelivr.net/npm/[email protected]/+esm';

  // Generate a QR code at render time
  const qrDataUrl = await QRCode.toDataURL('https://example.com', {
    width: 150,
    margin: 1
  });
  document.getElementById('qr').src = qrDataUrl;
</script>

<img id="qr" alt="QR Code" />

Async rendering with window.__RENDER_DONE__

When your template does async work (QR codes, charts, API calls), set window.__RENDER_DONE__ = true when the content is ready. The generator waits for this flag before capturing the page.

<script type="module">
  import QRCode from 'https://cdn.jsdelivr.net/npm/[email protected]/+esm';

  // Tell the generator we're not ready yet
  window.__RENDER_DONE__ = false;

  async function generateQR() {
    const qrDataUrl = await QRCode.toDataURL('https://example.com');
    document.getElementById('qr').src = qrDataUrl;

    // Signal that rendering is complete
    window.__RENDER_DONE__ = true;
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', generateQR);
  } else {
    generateQR();
  }
</script>

→ Read the complete QR Code guide

Response Format

On success the API responds with Content-Type: application/pdf and the raw PDF bytes in the body. Pipe it to a file or stream it to your storage.

HTTP/1.1 200 OK
Content-Type: application/pdf
x-ratelimit-limit: 500
x-ratelimit-used: 12
x-ratelimit-remaining: 488

%PDF-1.4 ...binary...

Error Codes