Local NotesComing soon
Write like no one's watching. Notes, notebooks, and an AI you can ask about anything you've written. It never leaves your phone.
On-device AI, made human
Private AI, run entirely on your device — built on QVAC
We're building apps that run AI entirely on your phone, powered by QVAC. No account, no cloud, nothing sent anywhere. The model comes to your data instead of the other way round.
Our mission
Intelligence you own.
The AI you rely on most knows your notes, your money, your health. Using it today means handing all of that to someone else, then hoping they look after it.
We think that's a bad trade, and an unnecessary one. Phones got fast enough. Models got small enough. The intelligence can run where your life already is: in your pocket, on hardware you own.
So that's what we build. Apps where the AI runs on your device, works without a signal, and answers only to you. No account to be locked out of. No subscription holding your files hostage. If we disappeared tomorrow, they would keep working.
Not your AI, not your intelligence. We'd rather it were yours.
The apps
Four apps. One private engine.
Each one is a specialist. They share the same on-device foundation, and none of them send your data anywhere.
Local ChatComing soon
A capable assistant with no one listening. Ask it anything, think out loud, work through a problem. The conversation happens on your device and stays there. Works on a plane.
Local MoneyComing soon
See where your money goes without handing your bank login to anyone. Snap a receipt, say what you spent, or bring in a statement. It's read on your phone and stays there.
Local LegalComing soon
Leases, contracts, policies. The documents that decide things, read and explained in plain language. It finds the clause you're looking for, and nothing is uploaded anywhere.
Why local
Your data never leaves your phone.
Most apps promise to keep your data safe on their machines. We don't have machines. The model runs on your phone, which means there's nowhere for anything to be sent, stored, or leaked.
Nothing leaves
Your notes, receipts, and documents are read on your phone and stay there. Not encrypted in transit to us. Never sent to us at all. There's no account, so there is nothing to breach.
It works anywhere
On a plane, in a tunnel, in a country that blocks the service. The model lives on your device, so it needs no permission from a network, or from us, to answer you.
Yours to keep
No subscription gates the thing you already installed. No account can be suspended. The intelligence is a file on your phone, and it keeps running whether or not we're still here.
How it works
Built with QVAC.
The AI inside our upcoming apps is powered by QVAC, Tether's open-source engine for running models directly on hardware you own rather than in someone's data centre. It is local-first, peer-to-peer, and free to use.
QVAC handles the intelligence. We handle everything you touch: the design, the words, and the sense that this is a tool rather than a service.
QVAC is Tether's open-source project, released under Apache‑2.0. We build on it as an independent company. LOCALHOST 41 INC. is not affiliated with, endorsed by, or a subsidiary of Tether.
chat & reasoning
semantic search
speech to text
reading documents
translation
all on-device
Open source · Apache-2.0
github.com/tetherto/qvac
github.com/tetherto/qvac
The team
Blog
What we're figuring out.
Notes on getting real models to run well on the hardware already in your pocket. Read everything ›
QVAC vs cloud AI
The difference between running a model on your device and sending your data to someone else's. A structural comparison, not a feature list.
Read
7 min
The complete guide to QVAC's 15 AI capabilities
Every AI capability in the QVAC SDK — text generation, embeddings, RAG, fine-tuning, multimodal, image and video generation, transcription, TTS, voice assistant, translation, BCI, VLA, OCR, and image classification. All on-device.
Read
6 min
What is QVAC?
QVAC is Tether's open-source platform for running AI models directly on your own device, with no cloud and no account. Here's what it is and why it matters.
Read
6 min
FAQ
Frequently asked questions.
What is localhost/AI?
localhost/AI is the studio name of LOCALHOST 41 INC., a company building consumer applications where the AI runs entirely on your own device. Its apps are Local Notes, Local Chat, Local Money, and Local Legal. None of them require an account, and none send your data to a server.
Does localhost/AI send my data to the cloud?
No. The AI models run on your phone. Your notes, transactions, documents, and conversations are stored on your device and are never transmitted. There is no account system and no server that receives your content.
What is QVAC?
QVAC is Tether's open-source platform for running AI models directly on your own hardware instead of in a data centre. It provides on-device text generation, embeddings, transcription, OCR, and translation through a single developer interface. localhost/AI builds its applications with QVAC.
Do the apps work offline?
Yes. Because the model is stored on your device, the apps work in airplane mode, in a tunnel, or in a country that blocks a given service. The only network request is the one-time download of the AI model.
Which apps does localhost/AI make?
Four: Local Notes (private notes with an AI you can ask about your own writing), Local Chat (an on-device assistant), Local Money (personal finance with no bank login), and Local Legal (reads and explains your own documents). All four are in development.
Why does Local Money not connect to my bank?
A live bank connection requires a cloud aggregator to hold a persistent token to your account, which would break the promise that nothing leaves your device. Instead, Local Money imports a statement file that is read and categorised on your phone, or you add expenses by receipt, voice, or hand.
Is localhost/AI free?
The apps have no subscription that gates access to software you have already installed, and no account that can be suspended. Because inference happens on your device, there is no per-query cost to pass on.