DOCX to PDF API for your application

The API exposes one endpoint: POST /api/convert. You send the DOCX as multipart/form-data in a field named file, with your API key in the Authorization header. The response is the PDF itself, as binary data with Content-Type: application/pdf, so you can write it to disk, stream it to your user or store it where you like.

Three response headers tell you where you stand: X-Credits-Used (credits consumed by this call), X-Credits-Remaining (credits left this month) and X-Credits-Limit (your monthly allowance). The conversion is the same as the one behind the online converter: the layout of the Word document is kept.

A first conversion from the command line:

curl -X POST https://www.hellodocxtopdf.com/api/convert \
  -H "Authorization: Bearer hpdf_your_api_key" \
  -F "file=@document.docx" \
  -o output.pdf

Every request must carry an API key in the Authorization header, as a Bearer token. Keys are created and managed in the Credentials section of your dashboard once you have subscribed to a plan. A request without a valid key gets a 401 response.

Authorization: Bearer hpdf_your_api_key

Usage is counted in credits: 1 credit per 5 MB of file size, rounded up. A 3 MB document costs 1 credit, an 8 MB document 2 credits, a 13 MB document 3 credits. Credits reset every month and unused credits do not roll over.

When the credits are exhausted the API answers 429 with a JSON body giving creditsNeeded, creditsRemaining, creditsLimit and resetAt, so your integration can wait or upgrade. The full detail of each plan is on the pricing page.

const formData = new FormData();
formData.append('file', docxFile);

const response = await fetch('https://www.hellodocxtopdf.com/api/convert', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer hpdf_your_api_key'
  },
  body: formData
});

if (!response.ok) {
  const error = await response.json();
  throw new Error(error.message);
}

const pdfBlob = await response.blob();
const pdfUrl = URL.createObjectURL(pdfBlob);

// Download the PDF
const link = document.createElement('a');
link.href = pdfUrl;
link.download = 'document.pdf';
link.click();

Python and Node.js examples, the list of status codes and the error format are in the full API documentation.