Offline Voice Dictation
System-wide push-to-talk dictation, zero network
Built by Nicholas Falshaw · System-wide push-to-talk on Windows · Fully offline
The problem
Windows Voice Access is cloud-based, unreliable, and loses context. Third-party dictation tools either require a subscription or send every word you speak to a remote server. For confidential work — client notes, medical, legal, security research — neither is acceptable.
What I built
An Electron tray app that registers a global hotkey (F9 by default). Hold F9, speak, release — the transcribed text appears in the active application, wherever the cursor is. No internet required. No telemetry. No subscription.
Architecture
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Tray process
Electron, minimal UI, persistent tray icon, global config
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Hotkey hook
uIOhook for true system-global key capture (works even when no window is focused)
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Audio capture
Node.js audio input stream, 16 kHz mono PCM, recorded while hotkey is held
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Transcription
whisper.cpp with GPU acceleration (CUDA / Metal / CPU fallback), configurable model size (tiny/base/small/medium)
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Text normalization
Punctuation restoration, common-phrase corrections, configurable dictionary
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Output
Clipboard-paste into the active application, or simulated keystrokes for apps that block paste
Tech stack
Outcome
F9 in any application — terminal, browser, email client, document editor — speak, release, text appears. No network calls. No cloud. Used daily for dictating technical notes and long-form content. Median transcription latency under one second per spoken phrase on a consumer GPU.