DocSpring vs HexaPDF

Fields you have versus fields you need

HexaPDF works with the structure inside a PDF. When a document contains AcroForm fields, you look them up by name, set values, and optionally flatten. It also creates fields, so you can build fillable forms in code. Its layout engine composes text, columns, and images for documents you generate from scratch.

DocSpring works with the page as you see it. Upload any PDF, and if it has fields DocSpring imports them with their positions. If it does not, drag fields where they belong. Either way the template is versioned, the API validates your JSON, and the same platform handles HTML templates, web forms, and signatures.

Feature comparison

Follow the feature links for details in DocSpring's documentation. Sources for each HexaPDF cell are listed at the end of the page.

Scroll the table sideways to see both products.

"Limited or your responsibility" marks things the library only partly covers or leaves to your own code and infrastructure. Plan requirements and product boundaries are noted in the cells.

Fill an application form with a name and email address

Suppose you have an application form as a PDF and your Ruby application knows the customer's name and email. Compare what happens when the PDF has fields, and when it does not.

Fill the form with HexaPDF

This is the best case, where the PDF already has fields named customer_name and customer_email.

require 'hexapdf'

# Works when the PDF already contains AcroForm fields with known names.
doc = HexaPDF::Document.open('application.pdf')
form = doc.acro_form
form.field_by_name('customer_name').field_value = 'Mira Patel'
form.field_by_name('customer_email').field_value = '[email protected]'

# Optional: flatten the fields so the values become fixed page content.
form.flatten
doc.write('filled.pdf')

Fill the form with DocSpring

The same values sent as JSON. The field positions were set in the browser and work for flat PDFs too.

curl --fail-with-body \
  "https://sync.api.docspring.com/api/v1/templates/${DOCSPRING_TEMPLATE_ID}/submissions" \
  --user "${DOCSPRING_TEST_TOKEN_ID}:${DOCSPRING_TEST_TOKEN_SECRET}" \
  --header 'Content-Type: application/json' \
  --data '{
    "test": true,
    "data": {
      "customer_name": "Mira Patel",
      "customer_email": "[email protected]"
    }
  }'

Set the environment variables to your template ID and test API credentials. Accounts in our EU region send requests to sync.api-eu.docspring.com instead. The response includes a download URL for a watermarked PDF. See the request and response guide.

Open a few of the real PDFs your application receives and list their field names. If half of them have no fields or names like Text12, that is the mapping work HexaPDF leaves with you.

Open source with a commercial license, plus your own time

Compare the commercial license plus a day of mapping work per messy PDF with a fixed monthly plan that includes hosted rendering, an editor anyone can use, and signing.

Moving from HexaPDF to DocSpring

Upload each PDF to DocSpring. Fielded PDFs import their fields and names, so your existing mapping mostly carries over as field names in the template. For flat PDFs, drag the fields into place instead of maintaining coordinates.

Replace the HexaPDF calls with a request through the DocSpring Ruby client. Choose per template whether output stays editable or is flattened. Keep HexaPDF if you still need in-process merging or encryption, or use DocSpring's combine PDFs API.

Test each form with long values and checkboxes, then remove the field-name mapping table from your code.

Discuss your documents with us.

Questions about HexaPDF and DocSpring

Can HexaPDF fill a PDF that has no form fields?

Only by creating fields or drawing text at coordinates you measure yourself. DocSpring's editor lets you place fields visually on any PDF, fielded or not, and imports existing fields when they are present.

Is HexaPDF free to use commercially?

HexaPDF is AGPL 3.0. Closed-source commercial use generally needs the commercial license offered by the author. Check the project site for current terms and prices.

Does DocSpring handle Ruby well?

Yes. DocSpring has an official Ruby client library, and the API is plain JSON over HTTPS. The template editor runs in the browser so non-developers can maintain templates.