Interactive PDFs use AcroForm fields — text boxes, checkboxes, radio buttons, dropdowns, and signature fields — to capture data. Before you submit a completed form, or when you inherit one to fill, it helps to see every field and its current value at a glance. This inspector reads the PDF in your browser and lists them, with no upload.
How it works
In the PDF format, each form field is a dictionary object that contains an /FT (field type) entry. The tool reads the file’s raw bytes, scans every indirect object, and for any object carrying /FT it extracts:
/FT— the field type:Tx(text),Btn(button),Ch(choice),Sig(signature)./Ff— flags that distinguish a checkbox from a radio group or push button./T— the field’s name, and/TU— its tooltip / alternate name./V— the current value, decoding both literal(...)and hexadecimal<...>PDF strings, including UTF-16 text with a byte-order mark.
The decoded fields are presented in a table of name, type, and value.
Example
A text field named applicant_name with a filled-in value renders as a row of applicant_name · Text · Jane Doe. A checkbox stores /On or /Off as its value, which the tool shows after stripping the leading slash.
When this tool is most useful
Before submitting a form. Interactive PDF forms have a long history of silently carrying pre-filled hidden fields — your name or partial address auto-populated from metadata, a stale date, or a checkbox you did not intend to change. Inspecting the field list before submission catches these.
When inheriting a partially filled form. If a colleague has started completing a form and you are taking over, seeing every field name and its current value saves opening every section manually to verify what has been answered.
Auditing a form template. Developers and compliance teams building or reviewing interactive PDF forms need to know every field’s name exactly as the PDF encodes it, because downstream automation, FDF import, and data-extraction scripts reference these names precisely. A typo in a field name breaks automated submission parsing.
Verifying signature fields. Signature fields (/Sig type) indicate where signatures should be applied. Inspecting them lets you confirm a document has the expected signature placeholders before distributing it.
Field types decoded
| PDF type code | AcroForm type | What it is |
|---|---|---|
Tx | Text | Single or multi-line text input |
Btn (checkbox flag) | Checkbox | On/Off boolean toggle |
Btn (radio flag) | Radio group | One-of-many radio button set |
Btn (push flag) | Push button | Action trigger button (not a value field) |
Ch (combo flag) | Dropdown/combobox | Select list with optional freeform entry |
Ch (list flag) | List box | Scrollable list with multi-select option |
Sig | Signature | Digital signature placeholder |
Notes
This is a deliberately lightweight, dependency-free reader. It will not decompress object streams (/ObjStm) or decrypt password-protected PDFs, and it surfaces a clear note when a form is present but stored that way. For everyday form auditing — confirming the right values are set and spotting stale hidden fields — it works entirely offline on your own device.