Capture on submit
Otto learns from every form you submit, including your edits — no manual data entry to get started.
Private autofill companion
Otto remembers every form you fill. And fills the next one for you.
A privacy-first browser extension that learns your data, keeps it encrypted on your device, and recognises fields on sites it has never seen — using on-device AI. Works offline. Your data never leaves your machine for the free features.
Notify me at launch
Coming soon to Firefox & Chrome
Launching on Firefox first, with Chrome close behind.
On your device
Works offline
No tracking
Zero-knowledge sync
How Otto works
Learns once. Recognises everywhere.
Otto turns the forms you already fill into an encrypted, on-device memory — then uses a tiered matching engine to fill new forms, even on sites it has never seen.
1
Otto learns
When you submit a form, Otto quietly remembers each field — including the corrections you make — and keeps it encrypted on your device.
2
Otto recognises
On any new form, a four-tier engine matches each field: exact recall, deterministic rules, on-device AI, then an optional LLM.
3
You fill
Click a teal chip to fill one field, or “Fill all” for the whole form. Hover any chip to see exactly why Otto filled it.
Tier 0Free · local
Exact recall
Reuses the exact value you filled on this form before.
Tier 1Free · local
Deterministic
Rule-based label, name & autocomplete matching.
Tier 2Free · local
On-device AI
Local embeddings match “e-mail address” to your stored email — offline, no network.
Tier 3Pro / BYO
LLM fallback
Resolves the fields nothing else can — via a privacy proxy or your own key.
Features
Everything you need. Nothing you don’t.
No accounts, no dashboards to learn. Otto works where you do — right inside the form.
Inline fill chips
A teal chip sits on each recognised field. Hover for provenance: label, source, tier and confidence.
On-device AI matching
Local embeddings (Transformers.js, WASM) recognise differently-worded fields — with no network call.
Knowledge base manager
Search, edit and merge everything Otto knows. Each entry tagged captured, uploaded or manual.
CSV & text import
Import a label,value CSV, or paste freeform notes and let Otto structure them into entries.
Zero-knowledge sync
Encrypt your knowledge base with a passphrase and sync across devices. The server only ever sees ciphertext.
Privacy by architecture
Your data lives on your device. Full stop.
- Encrypted locally. Your knowledge base is stored encrypted on your device, optionally behind a master passphrase.
- Works offline. Tiers 0–2 — capture, matching and fill — run entirely on your machine, with no network.
- No tracking, no telemetry. OttoFill collects nothing about you — no analytics, no ads, ever.
- Zero-knowledge sync. Optional sync encrypts before it leaves; the server only ever sees ciphertext.
- No account needed. Otto works the moment you install it — no sign-up, no login, nothing to create.
The one exception
When the on-device matcher can’t resolve a field, the optional Tier-3 LLM step can send that field to a model. It’s opt-in, off until you consent, and you can restrict it to field labels only — never values.
Turn it off entirely and Otto stays 100% local.
Pricing
Start free. Upgrade for Otto’s brain.
Everything that runs on your device is free, forever. Pro adds the cloud-optional pieces.
Free
Local
$0forever
Everything that runs on-device.
- Exact, deterministic & on-device AI matching
- Capture-on-submit learning
- Inline fill chips + provenance
- Knowledge base manager & CSV import
- Local vault lock
Pro
Beta
$3/ month
or $24 / year — free for everyone during early access.
- Everything in Free
- Tier-3 LLM fallback (privacy proxy or your key)
- Unstructured text import
- Zero-knowledge cross-device sync
- Priority on new features
Independent
Built by Bala Kumar.
OttoFill is an independent product — no investors to please, no data to sell. Just a privacy-first autofill tool built to work for you, not on you.
Give Otto your forms.
Keep your privacy.
OttoFill is coming to Firefox and Chrome. Get notified the moment it’s live.