One click fills any form with realistic test data, even custom dropdowns and date pickers. Free built-in AI: no API key, no account.
Users
28
store count
Rating
5.0 / 5
unchanged in 30 days
Ratings
8
total ratings
Store rank
#133K
#111K among extensions
Version
1.3.2
updated 6 Oct 2026
About Fillsmith — Free AI Form Filler & Test Data Generator
Stop typing test data. One click fills the whole form — every field, every custom dropdown, every date picker — with one believable person. Free, with AI that runs on your own computer: no API key, no account, no subscription.
WORKS WHERE OTHER FORM FILLERS STOP
Most fillers set a value and hope. That does nothing on the controls real apps are built from: a Select that is really a popup, a date picker that ignores typing, a rich-text editor that only accepts a real paste. Fillsmith works each control like a person: opens the dropdown and picks a real option, waits for lists that load from the server, clicks the day in the calendar — then reads the field back to check the page kept it.
• Custom selects, date pickers, rich-text editors and file uploads from the popular component libraries, and any control that follows ARIA
• Any web app, on localhost, staging or any other host
ONE PERSON, NOT RANDOM NOISE
• The email matches the name, the postcode matches the city, the phone matches the country
• Dates make sense together: a return date lands after the start date
• IBANs, VAT numbers and test card numbers pass their checksums
• English or German data, with addresses and phone numbers to match
VALID ON THE FIRST SUBMIT
• Respects min, max, step, maxlength and pattern
• A dropdown only ever gets one of its own options
• Required fields are never left empty
• File uploads get real generated files — PNG, PDF, CSV or JSON, whatever the field accepts
• Reads the validation messages and fixes what the form rejects; fills the fields that appear mid-fill
AI WITHOUT THE BILL
Fields no rule recognises go to Gemini Nano, the AI model built into Chrome. It runs on your machine: no API key, no account, no per-token cost, and your form never leaves the browser. The form is filled immediately; the AI's answers improve it as they arrive, so you never wait for it. Prefer a hosted model? Add your own Anthropic, OpenAI or Gemini key — or switch AI off entirely.
BUILT FOR REPRODUCING BUGS
• Pin a seed and get the exact same person again
• See where every value came from: which rule, what the AI was asked, where the time went
• Save a report of the last ten fills to attach to a ticket
FAST
Alt+Shift+F fills the page · Alt+Shift+D fills the focused field · Alt+Shift+R fills again as a new person · Alt+Shift+C clears. Or right-click → Fill this page.
FREE. REALLY.
No subscription, no Pro plan, no credits, no sign-up. No analytics, no tracking, nothing sent anywhere unless you add your own API key — and then only for fields no rule could answer: their labels, limits and options, the form's title and a few short texts from a table on the page, to the provider you chose. With the key as the only backend, the popup also checks that it works, with one test request of made-up data at most every ten minutes.
Privacy policy: https://github.com/vlad-artyomov/fillsmith/blob/main/PRIVACY.md
The built-in AI needs Chrome 138 or later and a one-time model download by Chrome (about 2 GB) on supported hardware. Without it, Fillsmith still fills every field it recognises.
Website and live demo: https://vlad-artyomov.github.io/fillsmith/
Open source (MIT): https://github.com/vlad-artyomov/fillsmith