Architecture, in one paragraph
Altypist is a self-contained macOS application. Audio is captured locally, transcribed locally by the open-source Whisper model running on the Apple Neural Engine, optionally tidied by a second local model, and inserted straight into whatever text field you were already using. There is no server in that path. After the one-time model download described below, Altypist performs no network request in order to transcribe anything — disconnect the machine from the network and dictation works exactly the same.
What happens on first launch
The recognition model is not embedded in the installer, so the first launch fetches it from Hugging Face — a normal HTTPS file download. This is the only moment Altypist needs an internet connection to function. The model is then cached in the app's support directory and reused offline from then on.
The first launch also asks macOS for two permissions: the microphone, and Accessibility. Accessibility is what lets Altypist type the finished text into the field where your cursor is; without it, Altypist falls back to the clipboard.
What does not happen
- No telemetry or analytics. There is no analytics SDK, no product metrics, no crash reporter, no “anonymous usage statistics”.
- No audio or text transmission. Recordings and transcripts are never uploaded — not to us, not to a third party, not for “model improvement”.
- No content logging. Altypist does not write dictated text or your custom vocabulary into system logs.
- No background synchronisation. Nothing is mirrored to iCloud or any other store. Altypist writes no transcript archive.
- No account. There is nothing to sign up for, so there is no profile, no password and no email on file from using the app.
The only network connections Altypist makes
| Destination | When | What it carries |
|---|---|---|
| Hugging Face | First launch, and if you switch model | A model file download. No data about you. |
| Altypist licence server | Activating, validating or deactivating a licence | The licence key, and a SHA-256 hash of the Mac's hardware UUID. Nothing else. The raw UUID is never sent. |
altypist.com/appcast.xml |
Update check | A plain file request for the update feed. |
That is the complete list. It is short enough to verify yourself — see “Verifying this” below.
Licensing, and what we can see
Because activation identifies a device by a one-way hash, we can tell that a device activated a given key, and how many seats are in use. We cannot tell which machine it is, who you are, what you dictate, or how often you use the app. The licence record holds the key, the tier, the number of seats, its status, an optional order reference and timestamps. The Privacy Policy lists it field by field.
If a licensed machine cannot reach the licence server, Altypist keeps working from its cached validation for a grace period rather than locking you out — an outage on our side must never stop your work.
Code signing and distribution
Altypist is signed with an Apple Developer ID certificate and notarised by Apple, which means Apple has scanned the build for malicious content and issued a ticket that is stapled to the download. Updates are delivered through Sparkle and are cryptographically signed with an EdDSA key; the app refuses an update whose signature does not verify.
Verifying this yourself
You do not have to take our word for any of it:
- Watch the network. Put Altypist behind Little Snitch, a proxy, or simply pull the network cable after the first launch, and dictate. It keeps working, and nothing leaves.
- Audit the engine. Recognition uses OpenAI's open-source Whisper model, which is publicly available and independently studied. The recognition behaviour is therefore inspectable in a way that a closed cloud service is not.
- Check the signature.
codesign -dv --verbose=4 /Applications/Altypist.appandspctl -a -vvv -t exec /Applications/Altypist.appwill show the Developer ID and the notarisation.
HIPAA-sensitive work
Built for HIPAA-sensitive workflows. Altypist doesn't transmit, store, or process any audio or text outside your Mac. Because nothing is ever sent to a server, Altypist removes the cloud-transmission risk that HIPAA compliance programs are built to prevent — there's no Business Associate Agreement to negotiate, because there's no data processor to negotiate one with.
Altypist is a local software tool, not itself a HIPAA-covered entity or service — this describes the architecture, not a compliance certification. Your own obligations, such as securing the Mac itself, remain yours.
Requirements
macOS 15 or later, Apple Silicon (M1 or newer). Intel Macs are not supported, because recognition runs on the Apple Neural Engine.
Questions from a review
If your IT or compliance team needs something this page does not cover, write to support@altypist.com and we will answer directly.