FillDef — Private PDF Filler & Web Form Autofill

About

FillDef is a private PDF filler — and this Chrome extension brings the same encrypted profile to web forms.

The main FillDef product is a web app at filldef.com that fills and signs fillable PDFs (W-9, NDAs, vendor onboarding, government forms, leases) entirely in your browser. PDF bytes never leave your device. This extension is the optional companion: install it when you also want one-click autofill on web forms — job applications, signups, tax portals — using the same encrypted profile. Your profile is encrypted on your device before it ever touches our servers — we can't read it.

✨ WHY PEOPLE INSTALL THIS

• You already use FillDef for PDFs and want web forms covered too.
• You're tired of password managers half-filling complex forms and giving up on the rest.
• You don't want a Chrome extension reading every keystroke and sending it to an AI server.

⚡ WHAT IT DOES

• Detects form fields on any page and maps them to your saved profile in milliseconds.
• A local pattern dictionary handles 80–90% of common English fields instantly, with no network call.
• Lets you click a field after fill to swap in a different saved value.
• Mirrors your profile (encrypted with AES-256-GCM) into browser.storage.local as a local cache so autofill works instantly and offline. The canonical copy lives encrypted on FillDef's servers (we can't decrypt it) — uninstalling the extension does not delete your profile.
• Shares one credit balance with the FillDef PDF filler. 3 fills are free every month, plus 5 trial fills in your first 30 days (PDF filler only); credit packs start at $1.99 and never expire.

🤖 HOW THE AI FALLBACK WORKS

For unusual or non-English field labels (e.g. "Steueridentifikationsnummer"), the extension sends the field LABEL only — no profile values, no page content, no document content — to a Gemini model via the FillDef Edge Function. The AI matches the label to a profile key like "tax_id." Your actual data never leaves the browser. You can verify in DevTools → service worker → Network: the only outgoing request body contains field labels.

🔒 PRIVACY ARCHITECTURE

• Profile encrypted with AES-256-GCM via the Web Crypto API. Encryption key derived from your account and never leaves your browser. We store only the ciphertext on our servers — we can't decrypt it.
• PDFs are processed by the web app at filldef.com using PDF.js + pdf-lib — fully client-side; PDF bytes never reach a server.
• AI requests carry only field labels (e.g. "First name"), never values.
• Manifest V3, no remote code, no analytics SDK in the extension.

✅ WHAT YOU NEED

• A free FillDef account (sign up at filldef.com — takes 30 seconds).
• Chrome (Firefox and Edge are on the roadmap).

🚫 WHAT IT DOES NOT DO

• Does not auto-submit forms — you always review before sending.
• Does not solve captchas or attempt anything bot-like.
• Does not record what you filled or where.
• Does not work on legal e-signature flows (DocuSign-style PKI).

🔗 LEARN MORE

• Web app: https://filldef.com
• Privacy details: https://filldef.com/privacy
• Pricing: https://filldef.com/pricing