Zero-click burner identity & OTP automation for signup forms.
FlashFill is a Chrome extension that eliminates the friction of throwaway sign-ups. It detects signup forms, generates a temporary identity, ghost-fills the form, and automatically handles OTP verification — all without a single click.
Open any signup page → FlashFill detects the form → fills it instantly → intercepts the verification email → injects the OTP. Done.
- Zero-click form filling — detects email/name/password fields and fills them automatically
- Temporary email generation — powered by Privatix Temp Mail via RapidAPI
- OTP auto-injection — polls the temp mailbox and injects verification codes in real time
- Magic link support — opens verification links automatically in the background
- Multi-step form support — MutationObserver + URL watcher handles SPA navigation
- Identity history — browse and reuse past burner identities with full detail recall
- Auto-verify toggle — control whether verification links open automatically
- Pause / resume — stop FlashFill from running on the current session
- Neubrutalist UI — Space Grotesk, neon yellow (#eaff00), hard black shadows
| Layer | Choice |
|---|---|
| Language | TypeScript |
| Build tool | Vite 4 + CRXJS |
| Identity generation | Faker.js |
| Email API | Privatix Temp Mail (RapidAPI) |
| Extension API | Chrome Manifest V3 |
| UI | Vanilla DOM — no React, no Vue |
- Node.js 18+
- A free RapidAPI account
- Subscribe to Privatix Temp Mail (free tier available)
git clone https://github.com/rushilbh27/getflashfill.git
cd getflashfill
npm install
npm run buildThen load the extension in Chrome:
- Open
chrome://extensions - Enable Developer mode
- Click Load unpacked
- Select the
dist/folder
Paste your RapidAPI key into the popup when prompted. That's it — FlashFill is now active on every tab.
src/
├── background/
│ ├── worker.ts # Service worker — message routing
│ ├── identity-manager.ts # Identity creation + temp email setup
│ └── polling-manager.ts # OTP polling loop
├── content/
│ ├── detector.ts # Form + email field detection
│ ├── injector.ts # Ghost-fill + OTP injection + toast UI
│ └── observer.ts # MutationObserver + URL watcher (SPA)
├── popup/
│ ├── popup.html # Extension popup
│ ├── popup.ts # Popup controller
│ └── popup.css # Neubrutalist styles
└── shared/
├── types.ts # Shared TypeScript types
├── messages.ts # Typed message contract (content ↔ worker)
├── storage.ts # chrome.storage.local wrapper
├── identity.ts # Faker.js identity generator
├── privatix-temp-mail.ts # Privatix API client
└── otp-extractor.ts # OTP + magic link extraction
1. observer.ts watches DOM mutations + URL changes
2. detector.ts finds signup forms by keyword + parent heuristics
3. injector.ts ghost-fills email, name, password with fake identity
4. Content script sends FORM_SUBMITTED → service worker
5. worker.ts spins up polling via polling-manager.ts
6. polling-manager polls Privatix API for new email in temp mailbox
7. worker.ts sends OTP_FOUND → content script
8. injector.ts injects OTP into verification field
See CONTRIBUTING.md for guidelines.
MIT — see LICENSE.