Fillsmith

Free · AI built into Chrome · No account

Fill any form with realistic test data. In one click.

Even the custom dropdowns, date pickers and rich-text editors other form fillers can't touch — with AI that runs on your own machine. No API key, no account, no subscription.

Add to Chrome — it's free Try the live demo

Free on the Chrome Web Store · Chrome 128+

Drives the components your app is built on

  • PrimeVue
  • MUI
  • Ant Design
  • react-select
  • Radix
  • Headless UI
  • Choices.js
  • Select2
  • Tom Select
  • vue-multiselect

…and any control that speaks ARIA, on localhost, staging or anywhere else.

Why testers switch

A filler that works the form like a person

Most form fillers set a value and hope. Fillsmith opens, picks, clicks and types — then reads every field back to check the page kept it.

Works where others stop

Opens the dropdown and picks a real option, waits for lists that load from the server, clicks the day in the calendar, pastes into rich-text editors.

One believable person

The email matches the name, the postcode the city, the phone the country. Dates make sense together. IBANs, VAT numbers and test cards pass their checksums.

Valid on the first submit

Respects min, max, maxlength and pattern. Dropdowns only get their own options. Required fields are never empty, and uploads get real generated files.

AI without the bill

Fields no rule knows go to Gemini Nano, the model built into Chrome. On your machine, no key, no per-token cost. The form fills at once; the AI improves it as it answers.

Reproduce any bug

Pin a seed to get the same person again. See which rule answered each field and what the AI was asked, and save one report for the ticket.

Private by design

No analytics, no tracking, no sign-up. Nothing leaves your browser unless you add your own Anthropic, OpenAI or Gemini key.

One click

Every field, and where its value came from

One press fills the whole page. The popup lists what each field got and why — a rule, the control's own type, one of its options, or the AI.

  • A card on the page says how many fields were filled and what was left
  • Fields that appear mid-fill are filled too
  • What a framework reverts is written again
The popup after a fill: eight fields, each with its value and a tag saying where it came from

Reproducible

Reproduce any bug with the same data

Every fill comes from a seed. Pin one and the next fill is the same person, down to the date — what you want when you are chasing a bug rather than finding one.

  • The decision trail: which rule answered, what the AI was asked
  • Where the time went, phase by phase
  • The last ten fills in one report to attach to a ticket
The Debug tab: the last fill, where the time went, what the model answered, and each field's decision

On-device AI

AI built into Chrome. No key. No bill.

Fields no rule recognises go to Gemini Nano, which Chrome runs on your machine. The form never waits for it: rules fill everything at once, and the AI's answers replace what they improve.

  • No account, no API key, no per-token cost
  • Your own Anthropic, OpenAI or Gemini key, only if you want one
  • Or switch the AI off entirely
Settings: the model on by default, the email domain, and an optional API key

The difference

What one click gets you

Fillsmith Many form fillers
Custom dropdowns, date pickers, editors Opened and picked like a person A value the widget ignores
The data One coherent person Random words per field
Validation Limits respected, checksums valid Rejected on submit
Checking its work Reads every field back Fire and forget
AI Built into Chrome, free None, or paid credits
Price Free, no account Often a subscription

Demo video

Forty-one seconds, sound on

The extension itself, filling real forms: the custom controls, one believable person, and the AI built into Chrome.

Live demo

Try it right here

  1. Add Fillsmith to ChromeFree, from the Chrome Web Store
  2. Press Alt+Shift+FOr click its icon, then Fill this page
  3. Watch the form fillA dropdown, a calendar, an upload and an editor
New release request — Fillsmith demo Open ↗

The live demo runs in Chrome on a computer, where Fillsmith is installed. Watch it fill a form instead.

FAQ

Questions

Is it really free?

Yes. There is no subscription, no Pro plan and no credits — one version, with everything in it. The code is open source under the MIT licence.

Do I need an API key for the AI?

No. Fillsmith uses Gemini Nano, the model built into Chrome, which runs on your machine. It needs Chrome 138 or later and a one-time download by Chrome of about 2 GB on supported hardware. Without it, the rules still fill every field they recognise. You can add your own Anthropic, OpenAI or Gemini key if you prefer a hosted model.

What does it send, and where?

By default, nothing — the rules and the built-in model run in your browser. Only if you add your own API key does anything go out: 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. There is no analytics and no telemetry. Read the privacy policy.

Will it work on my app?

On any page you can open in Chrome: localhost, staging, production. It drives native controls and the widgets of the common component libraries, and falls back to ARIA for the rest. If a field comes out wrong, report it — each fix ships with a test.

Can I get the same data twice?

Yes. Pin a seed in Settings and every fill produces the same person — what you want when you are reproducing a bug rather than finding one.

Stop typing test data.

One click, every field, one believable person. Free.

Add to Chrome — it's free