fnkey.ai

Hold Fn key, speak, paste transcribed text.

Install

1. Download from Releases:

   • Apple Silicon (M1/M2/M3): FnKey-arm64.zip
   • Intel: FnKey-x64.zip

2. Unzip and move to Applications:

   unzip FnKey-arm64.zip
   mv FnKey.app /Applications/

3. Set your Groq API key:

   mkdir -p ~/.config/fnkey
   echo 'your-groq-api-key' > ~/.config/fnkey/api_key

   Get a key at console.groq.com

4. Launch:

   open /Applications/FnKey.app

5. Grant permissions in System Settings → Privacy & Security:

   Permission	Purpose	How to Grant
   Input Monitoring	Detect Fn key press	Add FnKey.app via + button
   Microphone	Record voice	Prompted on first use, or add manually
   Accessibility	Auto-paste text	Add FnKey.app via + button

   Note: After rebuilding the app, you may need to remove and re-add it in these settings.

Usage

• Hold Fn and speak → raw transcription
• Hold Fn+Ctrl and speak → polished transcription (removes filler words, improves sentence structure)
• Release to transcribe and paste
• Click menu bar icon (○) → Quit to exit

The icon changes: ○ (idle) → ● (recording)

Build from source

./build-app.sh
cp -r FnKey.app /Applications/

Note: If cargo isn't found, run with login shell: /bin/bash -l -c './build-app.sh'

Features

• Whisper large-v3 - Full model for best accuracy
• Audio enhancement - DC offset removal, high-pass filter, peak normalization
• Config file - API key stored in ~/.config/fnkey/api_key
• Auto sample rate - Uses device's native sample rate

TODO

Features from Ito not yet implemented:

• Vocabulary hints - Send prompt with proper nouns/technical terms to improve accuracy
• No-speech detection - Use verbose_json response format and check no_speech_prob to skip silent recordings
• Custom dictionary - User-configurable word list for domain-specific terms

Notes

• Falls back to Option key if Fn not detected after 5s
• Floating red dot appears during recording

Known Limitations

Slight recording delay: There's a brief moment when you start speaking before audio capture begins. This is a deliberate tradeoff — eliminating this delay would require the microphone to be always active, showing the yellow indicator constantly. The current design prioritizes privacy: the microphone only activates when you press the Fn key.