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PDF AcroForm Filler

Fill standard PDF forms programmatically (text, checkbox, radio, dropdown/list) using JSON data injection

Programmatically fill PDF form fields and export a filled PDF.

Engine selection:

  • Primary library: pdf-lib

Supported injection:

  • Text fields
  • Checkboxes (true/false/yes/no)
  • Radio groups
  • Dropdown and option list selections

AcroForm/XFA behavior:

  • Fully supports AcroForm filling
  • For hybrid PDFs that include XFA, can remove XFA packet and fill AcroForm fallback fields
  • Pure XFA-only forms are not directly writable by pdf-lib and should be converted upstream

Example Results

2 examples

Fill Basic Registration Form

Inject text, checkbox, radio, dropdown and list values into an AcroForm PDF

pdf-acroform-filler-example1.pdf View File
View input parameters
{ "pdfFile": "/public/samples/pdf/form-sample-acroform.pdf", "fieldDataJson": "{\"full_name\":\"Alex Doe\",\"agree_terms\":true,\"tier\":\"pro\",\"country\":\"US\",\"hobbies\":[\"Reading\",\"Music\"]}", "removeXfaBeforeFill": true, "flatten": true, "strictMode": false }

Fill Without Flattening

Fill selected fields and keep form editable by disabling flattening

pdf-acroform-filler-example2.pdf View File
View input parameters
{ "pdfFile": "/public/samples/pdf/form-sample-acroform.pdf", "fieldDataJson": "{\"full_name\":\"Taylor Smith\",\"agree_terms\":false,\"country\":\"DE\",\"tier\":\"basic\"}", "removeXfaBeforeFill": true, "flatten": false, "strictMode": false }

Click to upload file or drag and drop file here

Maximum file size: 100MB Supported formats: application/pdf

JSON object where key = field name, value = field value

For hybrid PDFs, remove XFA packet and fill AcroForm fallback

Flatten fields to make result non-editable

Fail immediately when any field cannot be mapped/written

Key Facts

Category
PDF Tools
Input Types
file, textarea, checkbox
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

The PDF AcroForm Filler is a professional utility designed to programmatically populate standard PDF forms using JSON data. It supports text fields, checkboxes, radio buttons, and dropdown selections, allowing you to automate document workflows by injecting data directly into AcroForm fields.

When to Use

  • •When you need to generate hundreds of personalized documents from a single PDF template.
  • •When you want to automate the data entry process for standardized business or legal forms.
  • •When you need to convert interactive PDF forms into static, non-editable documents for distribution.

How It Works

  • •Upload your PDF form file that contains standard AcroForm fields.
  • •Provide a JSON object where keys correspond to the PDF field names and values represent the data to be inserted.
  • •Select whether to flatten the document to make it non-editable or keep it as an interactive form.
  • •Process the file to generate and download your completed PDF document.

Use Cases

Automating the generation of employee onboarding contracts or tax forms.
Batch-processing customer registration forms from a database export.
Creating personalized event registration tickets or certificates from a template.

Examples

1. Automated Registration Form Filling

Office Administrator
Background
The administrator receives user data in JSON format and needs to generate individual registration PDFs for a conference.
Problem
Manually typing data into PDF forms is slow and prone to human error.
How to Use
Upload the registration template, input the user data JSON, and enable flattening to finalize the documents.
Example Config
{"full_name":"Alex Doe","agree_terms":true,"tier":"pro","country":"US","hobbies":["Reading","Music"]}
Outcome
A completed, non-editable PDF registration form ready for immediate distribution.

2. Drafting Editable Contracts

Legal Assistant
Background
A legal assistant needs to pre-fill standard contract templates with client details but requires the lawyer to review and edit specific clauses later.
Problem
The document needs to be pre-filled but must remain interactive for final adjustments.
How to Use
Upload the contract template, provide the client details in JSON, and disable the 'Flatten Filled Fields' option.
Example Config
{"full_name":"Taylor Smith","agree_terms":false,"country":"DE","tier":"basic"}
Outcome
A pre-filled PDF document that remains fully editable for final legal review.

Try with Samples

json, pdf, video
PDF Samples
Generated PDF samples from tools dated 2026-02-01 to 2026-02-10
title token pdf
pdf, json
WebRTC Real-Time Communication Samples
Comprehensive WebRTC samples for peer-to-peer audio/video communication, data channels, screen sharing, and signaling server implementation
preferred input family json
json
Distributed Tracing Samples
Comprehensive distributed tracing examples using Jaeger, OpenTelemetry, and other modern observability tools for microservices architecture
preferred input family json
json
JWT Samples
Comprehensive JWT examples from basic token structure to advanced security implementations
preferred input family json
json

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FAQ

What types of PDF forms are supported?

The tool supports standard AcroForm PDFs. For hybrid PDFs containing XFA, the tool can remove the XFA packet to fill the AcroForm fallback fields.

Can I keep the PDF editable after filling it?

Yes, by disabling the 'Flatten Filled Fields' option, the resulting PDF will retain its interactive form fields.

What happens if a field name in my JSON doesn't match the PDF?

If 'Strict Mode' is enabled, the process will fail. Otherwise, the tool will skip the unmatched field and continue processing the rest.

Does this tool support pure XFA-only forms?

No, pure XFA-only forms are not supported. They must be converted to standard AcroForm format before processing.

Is there a limit to the file size I can upload?

The tool supports PDF files up to 100MB.

API Documentation

Request Endpoint

POST /en/api/tools/pdf-acroform-filler

Request Parameters

Parameter Name Type Required Description
pdfFile file (Upload required) Yes -
fieldDataJson textarea Yes JSON object where key = field name, value = field value
removeXfaBeforeFill checkbox No For hybrid PDFs, remove XFA packet and fill AcroForm fallback
flatten checkbox No Flatten fields to make result non-editable
strictMode checkbox No Fail immediately when any field cannot be mapped/written

File type parameters need to be uploaded first via POST /upload/pdf-acroform-filler to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-pdf-acroform-filler": {
      "name": "pdf-acroform-filler",
      "description": "Fill standard PDF forms programmatically (text, checkbox, radio, dropdown/list) using JSON data injection",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=pdf-acroform-filler",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]