Machine learning & AI playgrounds
Train, cluster, optimize and generate — classic machine learning algorithms you can poke at, running live in your browser.
Most popular
AI Learns to Drive (Neuroevolution)
Watch a population of neural-network cars evolve from crashing into corners to lapping a race track.
popular
Backpropagation Step-by-Step
Walk through one forward and backward pass of a tiny neural network, number by number.
popular
Decision Tree Builder
Grow a CART decision tree split by split and watch the partition map and tree diagram build together.
popular
Diffusion Model Toy
Train a tiny denoising diffusion model and watch it turn pure noise back into a 2D shape.
popular
Distribution Sketcher
Sketch the shape of a probability density — or paste raw data — and search 16 distributions for the ones that fit it best.
popular
Function Sketch Finder
Sketch a curve on a zoomable coordinate grid and search dozens of function families for the equations that fit it best.
popular
Gradient Descent Visualizer
Race SGD, Momentum, RMSProp and Adam across contour maps of five classic loss landscapes.
popular
Handwritten Digit Recognizer
Draw a digit and watch a neural network trained on MNIST recognize it live in your browser.
popular
LLM Tokenizer Visualizer
Train a small BPE tokenizer live in your browser and see exactly how any text splits into tokens.
popular
Linear Regression Playground
Place points, watch the least-squares line follow, and see gradient descent crawl across the loss surface.
popular
Neural Network Playground
Train a tiny neural network live in your browser and watch its decision boundary learn four classic datasets.
popular
Next-Token Sampling Playground
See the actual next-token distribution of a small language model and reshape it live with temperature, top-k and top-p.
popular
Overfitting Sandbox
Crank a polynomial’s degree on noisy data and watch the train/test error curves split apart.
popular
PCA Toy
Find the axes of maximum variance and flatten a point cloud onto them.
popular
Q-Learning Gridworld
Paint a gridworld and watch a Q-learning agent discover the best path by trial and error.
popular
ROC & Threshold Explorer
Drag a decision threshold and watch the confusion matrix, ROC curve and expected cost respond in real time.
popular
k-Means Clustering
Step through Lloyd’s algorithm and watch centroids chase the middles of your point clouds.
Supervised Learning
Decision Tree Builder
Grow a CART decision tree split by split and watch the partition map and tree diagram build together.
popular
Function Sketch Finder
Sketch a curve on a zoomable coordinate grid and search dozens of function families for the equations that fit it best.
popular
Linear Regression Playground
Place points, watch the least-squares line follow, and see gradient descent crawl across the loss surface.
popular
Overfitting Sandbox
Crank a polynomial’s degree on noisy data and watch the train/test error curves split apart.
Logistic Regression Playground
Paint two classes of points and watch logistic regression carve out its probability boundary by gradient descent.
Naive Bayes Classifier Demo
Score your own message with a word-count spam filter, or watch Gaussian naive Bayes classify 2D points.
Perceptron Learning Animation
Step through Rosenblatt’s 1958 learning rule and watch the decision boundary rotate with every mistake.
Random Forest Voting
Watch bagged, randomized trees vote a jagged boundary into a smooth ensemble decision.
SVM Playground
Train a support vector machine on 2D points and watch the margin, kernels and support vectors react live.
k-Nearest Neighbors Explorer
Hover a three-class map to watch the k nearest neighbors vote, and tune k against leave-one-out accuracy.
Gradient Boosting Step-by-Step
Stack shallow trees on residuals stage by stage and watch a 1D regression curve take shape — then overfit.
Unsupervised Learning
Distribution Sketcher
Sketch the shape of a probability density — or paste raw data — and search 16 distributions for the ones that fit it best.
popular
PCA Toy
Find the axes of maximum variance and flatten a point cloud onto them.
popular
k-Means Clustering
Step through Lloyd’s algorithm and watch centroids chase the middles of your point clouds.
Anomaly Detection Playground
Flag outliers three different ways and see where each score breaks down.
DBSCAN Clustering
Grow density-based clusters point by point and watch noise get left behind.
Gaussian Mixture & EM
Fit soft, elliptical clusters with the expectation–maximization algorithm.
Hierarchical Clustering & Dendrogram
Merge points bottom-up and cut the dendrogram wherever you like.
t-SNE Explorer
Watch high-dimensional clusters untangle themselves into a 2D embedding.
Self-Organizing Map
Watch a neuron grid teach itself the shape of the data — or organise random colors into a rainbow.
Neural Networks
Backpropagation Step-by-Step
Walk through one forward and backward pass of a tiny neural network, number by number.
popular
Handwritten Digit Recognizer
Draw a digit and watch a neural network trained on MNIST recognize it live in your browser.
popular
Neural Network Playground
Train a tiny neural network live in your browser and watch its decision boundary learn four classic datasets.
Activation Function Explorer
Compare sigmoid, tanh, ReLU and friends with their derivatives, and see why deep gradients vanish.
Convolution Filter Visualizer
Slide a 3×3 kernel over an image and watch convolution, ReLU and max-pooling build the output pixel by pixel.
Hopfield Network
Store pixel patterns in a Hopfield memory, corrupt them, and watch the network recall the original.
Self-Attention Visualizer
See how Transformer tokens attend to each other with arcs, heatmaps, heads and causal masks.
Word Embedding Trainer
Train word2vec skip-gram embeddings on your own text and watch words cluster on a live 2-D map.
Character RNN Text Generator
Train a recurrent neural network to write text one character at a time, live in your browser.
Regularization Demo (L1/L2/Dropout)
Fight overfitting live: watch L2 shrink weights, L1 zero them out and dropout smooth the decision boundary.
Vanishing & Exploding Gradients
Train a deep network live and watch per-layer gradients starve or blow up depending on init and activation.
Reinforcement Learning
AI Learns to Drive (Neuroevolution)
Watch a population of neural-network cars evolve from crashing into corners to lapping a race track.
popular
Q-Learning Gridworld
Paint a gridworld and watch a Q-learning agent discover the best path by trial and error.
CartPole Balancing AI
Balance the pole yourself, then watch the cross-entropy method evolve a policy that never drops it.
Multi-Armed Bandit Lab
Race ε-greedy, UCB1 and Thompson sampling on the same bandit and compare their regret.
Generative Models
Diffusion Model Toy
Train a tiny denoising diffusion model and watch it turn pure noise back into a 2D shape.
GAN Trainer (2D)
Pit a tiny generator against a discriminator on 2D toy data and watch mode collapse happen live.
Markov Chain Text Generator
Train an order-k Markov chain on any text and generate new text one token at a time.
Neural Cellular Automata Sandbox
Grow, damage and heal living textures driven by a tiny convolutional network in every cell.
Concepts & Metrics
ROC & Threshold Explorer
Drag a decision threshold and watch the confusion matrix, ROC curve and expected cost respond in real time.
Bayesian Updating Visualizer
Flip a coin and watch a Beta prior morph into a sharpening posterior in real time.
Bias–Variance Decomposition
See bias², variance and noise split a model’s error as 50 fits wobble around the truth.
Cross-Validation Visualizer
Animate k-fold splits and see why cross-validation beats a single train/test split.
Calibration & Reliability Diagram
Check whether predicted probabilities mean what they say, then fix them with temperature scaling.
Curse of Dimensionality
Watch distances concentrate and nearest neighbors fail as dimensions pile up.
Feature Scaling Demo
Run k-means and gradient descent on raw versus scaled features and watch scaling decide the outcome.
Optimization & Filtering
Gradient Descent Visualizer
Race SGD, Momentum, RMSProp and Adam across contour maps of five classic loss landscapes.
Kalman Filter Visualizer
Track a moving target through noisy measurements with a full linear Kalman filter.
Simulated Annealing TSP
Watch simulated annealing untangle a travelling-salesman tour as the temperature falls.
Particle Swarm Optimization
Fly a swarm of particles across classic test functions and watch it converge on the minimum.
Language Models
About these tools
Interactive machine learning demos: neural network training, gradient descent optimizers, clustering, dimensionality reduction, reinforcement learning and generative models. Every model trains locally in your browser on small 2D datasets you can edit, so you can watch the algorithm think — a hands-on way to build intuition for how machine learning actually works.