Fill PDF Forms

Fill PDF Forms via API

Upload your AcroForm PDF, send JSON data with field values, and download the filled document. Text fields, checkboxes, dropdowns — all handled in a single API call.

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How it works

Three steps to a filled PDF

From template upload to filled document in seconds. No libraries to install, no servers to manage.

Upload your PDF form

Upload any PDF with AcroForm fields via the API or dashboard. PDFForge automatically detects text fields, checkboxes, dropdowns, and radio buttons.

Send your JSON data

Make a POST request with your field values as JSON. Map field names to values — strings, booleans, or selections.

Download filled PDF

Get a signed download URL for the filled PDF. Optionally flatten the form to make fields non-editable.

Integration

Fill a form in one API call

Map field names to values as JSON. Strings for text fields, booleans for checkboxes, strings for dropdowns.

curl -X POST https://api.pdfforge.dev/v1/documents/fill \
  -H "Authorization: Bearer pk_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "template_id": "tpl_tax_form",
    "data": {
      "full_name": "Jane Smith",
      "date_of_birth": "1990-05-15",
      "agree_terms": true
    },
    "options": { "flatten": true }
  }'

Benefits

Why developers choose PDFForge for PDF forms

Purpose-built for programmatic PDF form filling. Fast, reliable, and simple to integrate.

Full AcroForm support

Text fields, checkboxes, radio buttons, and dropdowns. All standard AcroForm field types supported.

Flatten option

Flatten filled fields to make the PDF non-editable. Perfect for contracts, receipts, and official documents that should not be modified.

Sub-second processing

PDF form filling runs in-process without browser rendering. Most forms are filled in milliseconds — no browser rendering required.

Signed download URLs

Every filled document gets a secure, time-limited download URL. Share with clients or embed in your app without exposing API keys.

Sandbox mode

Test with pk_test_ keys to get watermarked documents at no cost. Switch to pk_live_ when you are ready for production.

Use your existing forms

No need to recreate your forms. Upload the PDF forms you already use — government forms, contracts, applications — and start filling them via API.

Comparison

Build vs. buy

Without PDFForge

With PDFForge

Install and maintain PDF libraries (pdf-lib, iText, PDFtk)

One API call — no dependencies to install or update

Write code to parse form fields and handle field types

Auto-detection of all field types on upload

Manage file storage, cleanup, and signed URLs yourself

Built-in cloud storage with automatic retention policies

Handle edge cases: fonts, encoding, field validation

Battle-tested engine handles all PDF edge cases

Build separate logic for flatten, checkboxes, dropdowns

Simple JSON mapping: field name to value, flatten as option

Self-host servers for PDF processing

Fully managed — scales automatically with your traffic

FAQ

Frequently asked questions

PDFForge supports standard AcroForm PDFs — the most common type of interactive PDF form. This includes text fields, checkboxes, radio buttons, and dropdowns (combo boxes). If your PDF has fillable fields that work in Adobe Acrobat or Preview, it will work with PDFForge.

XFA (XML Forms Architecture) is a legacy Adobe format that is not widely supported outside of Adobe products. PDFForge focuses on AcroForm, which is the modern standard. If you have XFA forms, you can convert them to AcroForm using Adobe Acrobat before uploading.

Templates can be up to 32 MB. Most PDF forms are well under 1 MB, so this limit is rarely a concern. If you have particularly large forms with embedded images, consider optimizing them before upload.

Flattening a PDF merges the form field values into the page content, making the document non-editable. The filled values become part of the page like regular text. This is ideal for contracts, receipts, or any document that should not be modified after filling.

PDFForge preserves the layout of your PDF form. Filled field values use the standard Helvetica font. For forms requiring specific fonts, ensure your PDF embeds them and includes proper appearance streams.

Yes — by default, filled fields remain editable. Only set flatten: true if you want to lock the values. This gives you flexibility: fill some fields via API and let end users complete the rest in their PDF reader.

7 days on Free, 30 days on Starter, 90 days on Pro, and 1 year on Business. Documents can be downloaded anytime before expiry via the signed URL or the API.

Absolutely. Upload your template once, then fill it as many times as you need with different data. Each fill operation creates a new document with its own download URL. The template remains unchanged.

Ready to generate your first document?

Start free with 50 documents per month. No credit card required. Up and running in under 5 minutes.

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