Fill PDF Form Fields — JSON, Local
Fill named AcroForm fields in a PDF from a JSON object. This does not detect printed blank spaces: a JSON key must match a real interactive field in the document for the corresponding value to be applied.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Keys must match the AcroForm field names inside the PDF.
How to use this tool
Enter exact field names as JSON keys and use actual boolean values for checkboxes, rather than strings such as "false". Consider the flatten option carefully if the recipient needs to edit the form later.
Results and examples
Open the saved PDF and check each field individually. Unknown names can be skipped and a document without form fields can be returned unchanged, so a successful download alone does not prove that the form was filled.
Worked example
For a PDF with actual Name and Agree fields, enter {"Name":"Ada","Agree":true} to fill text and a checkbox. Enable flatten for a final submission copy and verify that recipients no longer see editable fields.
Limitations
- Scanned blank forms or drawn boxes are not AcroForm fields and will not be filled.
- Unknown names can be ignored; use boolean false for an unchecked box, not the truthy string "false".
Fields
| Field | Guidance and constraints |
|---|---|
| Field values as JSON | Keys must match the AcroForm field names inside the PDF. |
| Flatten fields after filling | Check the unit and format displayed beside this field. |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
Is the visible caption always the JSON key?
No. The exact internal PDF field name is required.
Can a flattened form still be edited as a form?
Flattening removes that form-editing capability; retain an editable original if needed.
Related tools
You do not need to start over. Continue with the tool that fits your next step.
