Most AI lives somewhere else. On a server you do not own, behind a login, one outage or price change away from gone. We wanted to show, in the smallest possible way, what it looks like when the AI is just yours.
So we built a tiny brain. Open the takeaway, draw a digit from 0 to 9 with your mouse or finger, and a neural network reads it back to you. No sign-in to use it. Nothing you draw is uploaded. The whole thing, the model and the maths, runs inside your browser tab.
Under the hood it is a small neural network, the classic kind that learns to read handwritten digits, with about a hundred neurons in the middle. We trained it once, froze the weights, and shipped them inside the page. When you draw, your machine does the thinking. Your compute. Your data. Your side of the line.
It is a toy, and that is the point. If a digit-reader can run entirely on your side with zero cloud, so can the real thing: agents that read your inbox, draft your replies, and chase your follow-ups without a single byte leaving your control. The local brain is just the whole idea, shrunk small enough to hold.
Try it right here. Draw a digit from 0 to 9, lift your finger, and a neural network reads it, running entirely on your device. Nothing you draw is uploaded.
Live demo · runs on your device
1 · Write a digit (0 to 9)
Write it fairly big and roughly centred. The network reads the shape.
2 · The network reads it, neurons and all
?
Write a number and I will read it.
So what actually happened? (the honest, human version)
Your brain reads a handwritten 7 using billions of neurons firing in patterns it learned as a child. The reader you just used does the same job with a few hundred. That little picture on the far left of the diagram is what the machine sees: your drawing, shrunk and tidied to a tiny 28 by 28 grid, exactly the way it was taught to expect.
Those pixels flow into a layer of neurons. Each neuron adds up the brightness it cares about and fires a little or a lot. The diagram shows the most active ones lighting up, and the lines carry their votes toward the ten possible answers on the right. The orange lines push an answer up, the dark lines push it down. The digit with the strongest pull wins. No internet, no server, no magic, just numbers added up very fast, on your device.
It was trained once on thousands of real handwritten digits, and it carries that learning as a small set of numbers baked into this page. That is all an AI model really is: learned numbers, plus the patience to apply them. It gets clean digits right almost every time, and it will occasionally trip on a messy one, the same way you might squint at a stranger's handwriting.
Built by HeyOne AI · heyone.ai · runs on your device, nothing you draw is uploaded