JustScribe
Local-first live transcription app. Instant, private, and works offline.
Overview
Every transcription service on the market asks you to do the same thing: send your voice to someone else's server. For a lawyer reviewing client calls, a doctor dictating notes, or an executive in a board meeting — that's not just inconvenient. It's a liability.
JustScribe takes a fundamentally different approach. It processes all audio locally on your Mac using on-device machine learning. Real-time transcription from your microphone, system audio, or both — without an internet connection and with zero data ever leaving your machine. Not as a policy. As an architectural impossibility.
The Challenge
Cloud transcription services had trained users to accept a bad tradeoff: give up your privacy for accuracy and speed. We refused to accept that tradeoff. The goal was uncompromising:
- Match cloud accuracy and speed using only on-device processing
- Support real-time transcription with sub-second latency
- Handle multiple audio sources — mic, system audio, or both simultaneously
- Work with every app through native text insertion, no copy-paste
- Make it work offline, with no account, no sign-up, no telemetry
Technical Stack
- Platform: Native macOS with Swift and SwiftUI
- ML Runtime: Apple Silicon Neural Engine via Core ML
- Speech Models: Parakeet (optimized for fast English) and Whisper (50+ languages)
- Audio Capture: Core Audio for low-latency microphone and system audio
- Text Input: macOS Accessibility APIs for typing into any application
Key Features
Two Models, Zero Compromise
Parakeet delivers blazing-fast English transcription. Whisper covers 50+ languages. Switch between them in a click depending on what you need.
Capture Everything
Microphone for dictation. System audio for transcribing Zoom calls, podcasts, or meetings. Both at once for the complete picture. One app handles it all.
Type Anywhere, Instantly
JustScribe doesn't just transcribe — it types directly where your cursor is. Text editors, email, Slack, ChatGPT. No clipboard, no switching windows. You speak, it appears.
Truly Offline
No network requests. No analytics. No accounts. No telemetry. JustScribe is fully functional the moment you install it, whether you're on Wi-Fi, on a plane, or in a SCIF.
Results
Sub-second latency on Apple Silicon makes JustScribe viable as a daily dictation tool — not just a transcription utility. Early users report composing content roughly 4x faster than typing, transforming how they draft long-form writing, capture meeting notes, and interact with AI tools.
The local-only architecture has made it the tool of choice for professionals in fields where data sensitivity isn't optional — legal, medical, and executive contexts where cloud transcription was never an option.
Lessons Learned
- On-device ML has arrived: Apple Silicon's Neural Engine closes the gap with cloud services — the performance tradeoff that justified cloud is disappearing
- Privacy as architecture, not policy: when there's no server to send data to, privacy isn't a promise — it's a physical guarantee
- Accessibility APIs are an unfair advantage: building on macOS accessibility for text insertion means universal app compatibility without integrating with any of them