PDF form inspection and filling
List AcroForm field names, types and options, then fill supported fields using an explicit JSON mapping.
- 1Add input
- 2Adjust settings
- 3Get your result
Tool input and files are processed in this browser without being uploaded.
Before you start
Inspect one PDF to see its AcroForm field names, types and choices. Then switch to fill mode and map supported field names to JSON values.
How to use this tool
- Upload the PDF and inspect its exact field names, types and choices.
- Switch to fill mode and map exact field names to JSON values: strings for text and single choices, booleans for checkboxes.
- Download and reopen the saved form to verify field values and visible appearances. For a non-editable copy, use the separate flattening tool afterward.
Supported inputs and limits
One unencrypted PDF up to 30 MiB and 300 pages. Fill mode supports writable text, checkboxes and single selections; printable ASCII text and line breaks only in multiline fields. XFA is unsupported, and detected signatures are rejected for filling.
Inspection shows existing values except password fields, which are masked. The downloadable JSON may contain private data. Files stay in the browser; keep the original and verify saved appearances in a PDF reader.
Worked example
Example input
{"name":"Ada","approved":true}Example options
{"mode": "fill"}Example output
One-page editable PDF with name Ada and approved checked; both field values remain visible.
When something does not work
Inspect exact field names and choices first. Correct invalid or duplicate JSON keys, use printable ASCII for text, and keep an editable original. Signed or XFA PDFs need another workflow.
Frequently asked questions
How do I find field names before filling a form?
Upload the PDF in Inspect fields mode. The table shows exact names, types, choices and read-only status; download JSON for the full report.
What should the example produce?
With name and approved fields, {"name":"Ada","approved":true} keeps both fields editable and fills their visible values.
Which cases are outside its scope?
XFA is unsupported. Fill mode rejects detected signatures, read-only fields, unsupported characters and multi-select lists. This tool does not guarantee identical behavior in every PDF reader.