Neural Net Playground

Train a neural network from scratch in your browser — watch the decision boundary form as it learns. Backprop hand-written in JS, no ML library.

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class 1 class 0
Epoch0
Train loss—
Train accuracy—
Loss curve

Each pixel is colored by the network's prediction; dots are the training data. Everything — forward pass, backpropagation, SGD — runs in app.js with no dependencies.