Research → Implementation → Failure → Recovery → Pattern → Production

Build AI-native systems.

Learn AI, DSA and systems by building them, right in your browser.

We don’t teach tools, we teach systems: the ideas that built modern computing, the failures that taught us how to run it, and the labs to prove you can. AI, cloud, security, data, and production, all connected.

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No install · no Docker · no setup, just your browser. 5 courses 100% free.

28 courses ↓ 547 video lessons 394 hands-on labs 161 papers & cases 🔄 daily review

🎯 Prepping for placements?A guided path through DSA, system design & the fundamentals, learn each interview round by doing. 📋 Am I ready? 2-min Placement Prep →

Try it now, no signup

Drag a knob, watch the algorithm move. Each takes about 2 minutes.

All playgrounds →

Placement · DSA

Sorting Race

Insertion vs merge vs quick sort, same array. Guess who wins.

Placement · DSA

DP Table: LCS & Edit Distance

Watch every cell fill from its neighbours, then trace the answer.

Placement · DSA

Number of Islands

Paint a map, let BFS flood it. The classic interview grid.

AI · most played

Embeddings

See how AI turns words into points, and meaning into distance.

AI · how ChatGPT works

Attention

Which words is the model looking at? Move it and find out.

AI · deep learning

Neural Network

Train a tiny network live and watch it learn the boundary.

Free forever · runs in your browser · works on your phone

The 7 Levels of Mastery

Your journey, one rung at a time, each level reuses everything below it.

🎥 Language

1The Programmer AKA The HackerWrite real Python & SQLPython · SQLfree 2The Data Practitioner AKA The DetectiveTurn raw data into insightpandas · EDAfree 3The ML Engineer AKA The AlchemistBuild systems that decideML · Deep Learning 4The Systems Engineer AKA The GuardianShip it. Keep it alive at 3 AM.MLOps · DevOps · Security 5The AI Engineer AKA The MagicianBuild agents that do real workLLMs · RL · Agents 6The AI Architect AKA The MastermindOrchestrate organizations of agentsAgentic AI · Leadership 7The AI-Native Founder AKA The VisionaryDesign a company of humans + agentsCapstone

Not sure where you are? See your journey › · Browse concepts ›

16 tracks · SQL · pandas · Python

Practice makes perfect

Practice Hub

Think like the business, then answer it three ways — SQL, pandas & Python, side by side. Thousands of browser-graded questions; the Data Skills ladders are free.

Start practising, free →

25 projects · 20 run in-browser

Build · Prove · Portfolio

Projects

Build real ML models end to end — supervised, unsupervised, deep learning & paper reproductions. Every notebook is verified to run; most run right in your browser. 3 free to try.

Explore the projects →

Interactive Playgrounds

Don’t just read it, turn the knob.

Every big idea here has a live playground: drag a slider, watch the output move, feel the intuition. 105 interactive labs, including 18 landmark AI papers rebuilt as live demos (DQN, GANs, diffusion, LoRA, RoPE, Mixture-of-Experts, speculative decoding, RLHF…), plus tokenizers, attention, the KV-cache, loss functions, RAG scoring, quantization and system design.

⛰

Gradient Descent

How a model actually learns, ride the loss curve downhill, pick the step size.

Temperature & Sampling

Drag one knob and watch an AI choose its next word, safe, or unhinged.

Tokenizer

Watch text shatter into tokens, and why it costs money.

Attention

See which words a transformer looks at, live.

Binary Heap & Priority Queue

Push bubbles up, pop-min sifts down, the O(log n) structure behind every priority queue.

Trie & Autocomplete

Store words as a tree of characters, shared prefixes once, every completion in O(L).

Quickselect & the k-th Largest

Partition around a pivot, recurse into one half, the k-th largest in O(n), no full sort.

Dijkstra’s Shortest Path

Settle the nearest node, relax its edges, watch the shortest route turn out to be the long way round.

N-Queens & Backtracking

Try a choice, hit a wall, back up, watch queens solve the board by backtracking.

Word2Vec

king − man + woman = queen, do algebra on meaning.

Optimizer Race

SGD, Momentum, RMSProp and Adam race down the same loss surface.

GANs

A forger and a critic in an arms race, until the fakes look real.

Diffusion

Generate images by denoising pure noise, one step at a time.

Deep Q-Learning

An agent learns to act from reward alone, the idea behind game-playing AI.

RLHF Reward Model

Turn “this answer is better” into a number a model can optimize.

Speculative Decoding

A small draft model makes a big one 2–4× faster, provably identical output.

Cross-Entropy Loss

Why one confident mistake costs more than a hundred hesitant ones.

Dropout

Switch off neurons at random, and the net stops overfitting.

BatchNorm vs LayerNorm

Same matrix, perpendicular axes, and why transformers pick LayerNorm.

Self-Attention from Scratch

Five words, three vectors each, watch them decide who to listen to.

Multi-Head Attention

Run attention several times in parallel, the same word routed two ways at once.

Positional Encoding

Attention is order-blind, so stamp every position with a sine/cosine fingerprint.

Rotary Embeddings (RoPE)

Encode position by rotation, the attention score then depends only on relative distance.

Inside a Transformer Block

Kill residuals or LayerNorm and watch a 48-layer net explode.

🔒 Pro 🗃️

The KV-Cache

Why LLM text generation is O(n), not O(n²), cache the past.

Mixture of Experts

Route each token to just its top-k experts, a trillion params, a fraction of the compute.

🔒 Pro 🗜️

Quantizing a Model

Shrink a 14 GB model to 3.5 GB, then rescue the outliers.

LoRA Fine-Tuning

Fine-tune with two skinny matrices, 600× fewer params.

Beam Search vs Greedy

Greedy grabs the top word and gets trapped, beam keeps the top-b paths and finds a better sentence.

Scoring a RAG Pipeline

Watch a RAG answer stop hallucinating as recall completes.

Consistent Hashing

Add a server, move 1/N of the keys, not 90%.

Bloom Filters

A set in 32 bytes that never says “no” by mistake.

▶ Explore all 105 playgrounds 69 free · 36 Pro, no install, just your browser