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Defense-first

Fill any form.
Defend every value.

FillDef autofills web forms and PDFs from one encrypted profile that lives on your device. AI only ever sees field labels — never your data.

Start free — 5 fills/monthSee how it works

No subscription · Credits never expire · Verifiable in your browser

AES-256-GCM encrypted
Stored on your device
Verifiable in your browser
No subscription

How it works

1

Save your profile

Once. Encrypted in your browser or extension. Never on our servers.

2

Click Fill

Web forms autofill instantly. Fillable PDFs let you pick free or paid credit before mapping runs.

3

Review & download

Edit any field, place your signature, download. One credit covers the upload and every re-download.

Web forms

Filled before you blink.

A local pattern dictionary handles 80–90% of fields the moment you click Fill. No round-trip to a server, no waiting for AI. Odd labels — “Steueridentifikationsnummer”, “Mother’s maiden surname” — go to AI as labels-only.

  • Pattern matches in milliseconds, fully offline.
  • Inline override badges to swap a saved value into any field.
  • AI fallback only on the fields that actually need it.
application.gov/form
Full name
Satrio Wisnugroho
Email
wisnugrohosatrio@gmail.com
Phone
+62 812 3456 7890
Address
Jl. Pattimura 14, Jakarta
4 fields filled · 0 sent to a server
The PDF tweak surface

Fill it. Fix it. Sign it.
Without spending another credit.

Other PDF fillers commit on click. Wrong field? Re-upload. Misplaced signature? Re-upload — and pay again. FillDef opens every fill in a review surface so you can correct, restyle, and place your signature exactly where it belongs. One credit covers the upload and every re-download.

Works with fillable PDFs — forms with real input fields built in (W-9, government forms, most insurance and HR docs). Scanned-image PDFs aren’t supported, and you’re told before any credit is spent.

✎ signature
2 of 3 tweaks leftFree fill
Typography
Paid
Helvetica
11pt
Unlocks on any paid fill → font + size 8–24pt
Fields
Full name
Satrio Wisnugroho
Date of birth
1995-03-12
Tax ID
edited
94-3849201
Address
Jl. Pattimura 14, Jakarta

Edit before you commit

Every auto-filled value is editable in place. Wrong middle name? One click. Free fills get 3 corrections — revert refunds the action.

Click-to-place signature

Save your signature once. Click anywhere on the PDF to drop it. Paid fills make it draggable and resizable.

Restyle the whole document

Paid fills unlock font family and size (8–24pt). Standard fonts only — no font-bundle bloat.

Try the PDF filler
Privacy by architecture

Defense isn’t a policy. It’s how we built it.

Profile stays on your device

AES-256-GCM encryption with a key derived from your account. Our servers never see it.

AI sees labels, not values

When the local dictionary misses, only the field label — for example, "Steueridentifikationsnummer" — is sent. Never your tax ID.

PDFs never leave the browser

Upload, map, fill, sign, download — all client-side. The file never reaches a server.

Read the full defense story →

Why not just LastPass or Adobe?

Password managers half-fill web forms. Adobe handles PDFs but charges every month. FillDef does both — and only when you ask.

FillDefPassword mgrsAdobe Acrobat
Fills web forms
partial
Fills PDF forms
Edit before submit
partial
Place signature anywhere
Data stays on device
partial
No subscription

Pay once. Fill forever.

No subscription. Credits never expire. 5 fills are free every month — buy a pack only when you outgrow it. Power pack is $0.013 per fill, less than two cents.

See pricing

Questions, answered.

What happens if I uninstall the extension?
Your profile is stored locally, so it's tied to that browser. Uninstalling deletes it. Export is on the post-MVP roadmap; for now we recommend re-saving your profile in another browser if you switch. We warn before uninstall.
Why credits instead of a subscription?
You shouldn't pay every month for a tool you use twice a quarter. Buy 100 credits for $2.99, use them in 6 months or 6 years — they never expire. Five fills are free every month, no card required.
How can I verify what FillDef sends to the AI?
Open DevTools → Network when you click Fill. The only AI-related request is a POST to /fields-map, and only when the local dictionary misses. Click it to inspect the body — you'll see field labels and form attributes, and nothing from your encrypted profile.
What does AI cost me?
Nothing extra. AI fallback only runs on field labels the local dictionary can't match (~10–20% of fields). One fill costs one credit, whether it's pure dictionary, pure AI, or a mix.
How do free vs paid PDF fills work?
Before each PDF is mapped, FillDef shows a Choose-credit screen with your free-fill quota (5/month) and your paid balance side by side. Free fills cap PDF tweaking at 3 actions and one fixed-size signature; paid fills unlock unlimited tweaks, font controls, and a draggable signature. You decide every time.
What kind of PDFs work?
Fillable PDFs — files with real input fields built in (W-9, most government forms, insurance and HR documents). If you can click a field in Acrobat or Preview and a cursor appears, FillDef can fill it. Scanned-image PDFs aren't supported, but FillDef detects this on upload and tells you before any credit is spent.
Can I use FillDef without installing the extension?
Yes. The web app fills PDFs entirely in your browser. The extension adds web-form autofill on top.
Do you store the PDFs I fill?
No. PDFs are read, filled, and downloaded entirely inside your browser. The bytes never reach our servers.

Five fills a month, no card required.

No trial countdown. No “downgrade to free” dark patterns. Buy credits only if you outgrow the free tier — and they never expire.

Get FillDef freeHow we defend your data