What Is QVAC? A Plain-English Guide to Tether's On-Device AI
QVAC in plain English, no jargon — what it is, why it's different from cloud AI, and where you'll actually see it.
If you've seen "built on QVAC" and wondered what that means, here's the short version: QVAC is technology that runs AI directly on your own device instead of in a data center somewhere. No cloud. No account. Nothing about you leaving your phone.
This guide explains it in plain English — no jargon required.
The core idea
Most AI you use today works like this: you type something, it gets sent to a company's servers, powerful computers there figure out an answer, and it comes back to you. Useful — but your words made a round trip to someone else's building.
QVAC flips that. The AI model runs on your device — your phone, your laptop. Your data stays where it is. The model comes to you instead of you sending your data to the model.
Who makes it
QVAC is built by Tether — the company behind the USD₮ stablecoin — and released as open-source software (anyone can inspect or use it). Tether launched the QVAC SDK publicly in April 2026, after previewing the broader initiative in late 2025.
It's worth separating three things that get mixed up:
- QVAC is the engine — Tether's technology for running AI on-device.
- Apps built on QVAC (like Tether's own QVAC Workbench and QVAC Health, or our upcoming Local Notes and Local Money) are the products people actually use, or will soon.
- The engine and the apps are different layers: QVAC powers them, but each app is its own experience.
What it can actually do
QVAC isn't just chatbots. It runs a whole range of AI tasks locally:
- Chat and writing — a language model answering questions, drafting, summarizing.
- Transcription — turning speech into text.
- OCR — reading text out of photos and documents.
- Translation — between languages, on-device.
- Embeddings and search — understanding meaning so you can search your own stuff intelligently.
- RAG — answering questions using your own documents as the source.
All of it without an internet connection, once the model is downloaded.
Why it matters
Privacy that's real, not promised. With cloud AI, "we protect your privacy" is a promise about what a company does with data you already sent them. With QVAC, there's no server to send data to — so there's nothing to leak, sell, or hand over. Privacy is the architecture, not a policy.
It works offline. On a plane, in a tunnel, off the grid — the AI still works, because it's running on the device in your hand.
No per-use cost. Because it runs on your hardware, there's no meter ticking with every question.
It's open-source. You don't have to trust a black box; the engine is public and auditable.
Where you'll see it
Tether ships its own apps on QVAC — QVAC Workbench (a local AI assistant) and QVAC Health (a private health tracker). And independent studios build on it too: at localhost/AI, we're building Local Notes (private AI notes) and Local Money (private finance) entirely on QVAC — both coming soon.
That's the whole point of QVAC being open — anyone can build private, on-device apps on it.
Want to go deeper?
For the technical version and the full studio story, see What Is QVAC — and Why We Built localhost/AI On It. For developers, see QVAC SDK Explained.