Detect and block invisible meeting transcription tools. Protect your meeting privacy from AI notetakers recording without your consent.
Nullify is a free, open-source desktop app that detects hidden meeting transcription software (like Granola, Otter.ai, Fireflies, Read.ai, tl;dv, Fathom, Supernormal, Tactiq) running on your computer and shields your audio in real time so these tools can't transcribe your conversations.
AI meeting assistants like Granola run silently in the background, capturing your system audio and transcribing everything you say during calls — often without a visible indicator. Other tools like Otter.ai, Fireflies, Read.ai, and tl;dv do the same. You may not even know your meetings are being recorded and transcribed.
Your voice. Your meetings. Your choice.
Nullify combines two layers of protection:
- Process scanning — continuously monitors running processes for known transcription tools (Granola, Otter.ai, Fireflies, Read.ai, tl;dv, Fathom, Supernormal, Tactiq)
- Network monitoring — detects connections to transcription API endpoints (Deepgram, AssemblyAI, etc.)
- Real-time alerts — instant notification when a transcription tool is detected
- Psychoacoustic masking — injects inaudible perturbations that confuse speech-to-text models
- Phoneme injection — adds adversarial audio patterns that increase Word Error Rate (WER) up to 90%+
- Multiple protection levels:
- Stealth — imperceptible to humans, +15-25% WER
- Moderate — faint background hum, +40-60% WER
- Strong — noticeable noise, +70-90% WER
- Maximum — full disruption, transcription completely unusable
- Low latency — under 50ms audio processing delay
- Detects Granola, Otter.ai, Fireflies, Read.ai, tl;dv, Fathom, Supernormal, Tactiq and more
- Works on macOS and Windows
- System tray integration — runs quietly in the background
- Real-time activity log showing all detection events
- Audio level meter for monitoring shield output
- Auto-start shield on detection option
- Configurable scan intervals and protection levels
- Dark UI optimized for quick glances during meetings
Pre-built binaries are available on the Releases page:
- macOS —
.dmg(Intel & Apple Silicon) - Windows —
.exeinstaller
# Clone the repository
git clone https://github.com/khaoss85/nullify.git
cd nullify
# Install dependencies
npm install
# Run in development mode
npm run dev
# Build for production
npm run build
# Package the app
npm run package:mac # macOS
npm run package:win # Windows| Concern | Nullify's Answer |
|---|---|
| Granola records my meetings without asking | Detects Granola and blocks its transcription |
| Otter.ai joins calls silently | Monitors for Otter processes and API connections |
| I don't know if Fireflies is listening | Real-time scanning with instant alerts |
| Read.ai is on my work laptop | Process-level detection catches it immediately |
| I want privacy during video calls | Audio shield makes transcription unusable |
| I need proof something was recording | Activity log with timestamps for every detection |
| Tool | Process Detection | Network Detection |
|---|---|---|
| Granola | Yes | Yes (Deepgram API) |
| Otter.ai / OtterPilot | Yes | Yes (AssemblyAI API) |
| Fireflies | Yes | Yes |
| Read.ai | Yes | — |
| tl;dv | Yes | — |
| Fathom | Yes | — |
| Supernormal | Yes | — |
| Tactiq | — | Yes |
- Electron — cross-platform desktop app
- React 19 + TypeScript — modern UI
- Tailwind CSS 4 — styling
- Zustand — state management
- electron-vite — fast build tooling
- Browser extension detection for Chrome-based transcription plugins
- Custom signature editor — add your own detection rules
- Automatic signature updates
- Meeting privacy report exports
Yes. Nullify runs on your own computer and only affects audio on your own device. It does not interfere with other people's software — it protects your audio output from being transcribed without your consent.
Nullify does not kill or block any process. It detects transcription tools and optionally applies audio perturbation so that the transcription quality degrades significantly — making the output useless to the recording tool.
At the Stealth level, the perturbations are designed to be imperceptible to human ears while still confusing speech-to-text models. Higher levels introduce progressively more audible noise.
Yes. Nullify monitors your system-level audio and processes, so it works regardless of which video conferencing platform you use.
Custom signature support is on the roadmap. Currently the detection covers the most common AI meeting assistants.
Contributions are welcome! Feel free to open issues and pull requests.
MIT
Stop invisible meeting transcription. Take back your audio privacy.
Nullify — because your meetings should be yours.