Fill PDF form

As one JSON object mapping field name to value, for example {"Name": "Ada", "Agreed": true}. The names must match the form's field names exactly, including case and spaces. Leaving the box empty is refused with a message showing that example, and text that is not valid JSON gets its own message asking for the same shape.

Run Extract PDF form data on the same PDF first. It gives you every field name with its type and current value as JSON, which you can edit and paste straight back in here. If you guess wrong, this tool lists every real field name in its error, so a failed attempt tells you the answer.

Text fields, checkboxes, dropdowns, option lists and radio groups. A text field takes any value converted to a string, and null becomes an empty string. A checkbox is checked when the value is truthy, so use true and false. Dropdowns, option lists and radio groups take the option string you want selected.

A name that does not exist is skipped and reported afterwards under a "no such field" line, so a typo in one entry does not stop the others. If none of your names match, the run fails and the message lists every field name in the form. A PDF with no fields at all gets "this PDF has no form fields to fill".

Yes. The result is still a live form, so the fields stay editable in any PDF reader. Run PDF flatten on the output if you want the answers locked into the page. The file comes back with a -filled suffix and your original is untouched.

No. The JSON never leaves the page. It is parsed in this tab, applied to the document by pdf-lib in a Web Worker, and the result is handed back as a download. Given that form values are usually names, addresses and account numbers, that is the whole reason this tool exists here.