| name | pdf-form-filler |
| description | Fill PDF forms programmatically using pypdf library. Use this skill whenever you need to fill in PDF forms with field data, extract field names from PDFs, or generate filled PDF documents. Essential for automating form completion tasks. |
PDF Form Filler
Overview
Fill interactive PDF forms programmatically using the pypdf library. This skill handles reading form fields, populating them with data, and saving the result.
Library Setup
from pypdf import PdfReader, PdfWriter
The pypdf library is the primary tool for PDF manipulation in Python 3.8+.
Key Operations
1. Reading PDF Form Fields
Discover available fields in a PDF form:
from pypdf import PdfReader
reader = PdfReader("form.pdf")
if reader.get_fields():
for field_name, field_info in reader.get_fields().items():
print(f"Field: {field_name}, Type: {field_info.get('/FT')}")
else:
print("No form fields found")
Output: Dictionary of field names and their types (Text, Button, Choice, etc.)
2. Filling Form Fields
Populate form fields and save the filled PDF:
from pypdf import PdfReader, PdfWriter
reader = PdfReader("blank_form.pdf")
writer = PdfWriter()
for page in reader.pages:
writer.add_page(page)
update_page_form_field_values(
writer=writer,
fields={
"field_name_1": "value 1",
"field_name_2": "value 2",
}
)
with open("filled_form.pdf", "wb") as output_file:
writer.write(output_file)
3. Common Field Types
- Text fields: Simple string input (
/FT = "/Tx")
- Button/Checkbox fields: Boolean values (
/FT = "/Btn")
- Choice/Dropdown fields: Select from options (
/FT = "/Ch")
- Signature fields: Reserved for signatures (
/FT = "/Sig")
Field Value Format
When filling fields:
- Text: String values work directly
- Checkboxes: Use "On"/"Off" or True/False
- Radio buttons: Use the specific option value
- Dates: Format as string (e.g., "01/15/2026")
Date Format Handling
Always confirm the expected date format before filling. Common formats:
MM/DD/YYYY (US standard)YYYY-MM-DD (ISO format)- Check the form specification for requirements
Troubleshooting
Fields not appearing after filling:
- Verify field names match exactly (case-sensitive)
- Confirm field exists using
get_fields()
- Some fields may be read-only or hidden
Empty values overwriting existing data:
- Only pass fields you want to fill in the dictionary
- Empty strings may clear field values
See Also
