The practice room

Practice until confidence feels natural.

Pick a track, work through it at your own pace, and run your solution against real test cases. A companion reads your code afterwards and tells you what an interviewer would.

Problems: 125
Solved: 0
Live tracks: 2

Choose a track

Judged by a sandboxed runner

Track 01

Data Structures & Algorithms

cpp

The interview core: arrays and strings through trees, graphs and dynamic programming. Every problem is judged against real test cases.

Foundations
Intermediate
Advanced

0 of 75 solved 0%

Open

Track 02

C++

cpp

The language itself — syntax, types and control flow, then classes, RAII, inheritance and polymorphism. Every problem is judged against real output.

Foundations
Object-Oriented C++

0 of 50 solved 0%

Open

Track 03

JavaScript

javascript Coming soon

The language as interviewers actually probe it — equality and cloning, currying, and the event loop rules that decide what runs when.

Language core
Async and the event loop

We’re preparing the lessons and test cases. This track will open soon.

Track 04

React

javascript Coming soon

The machinery under the library: the hook dispatcher, effect dependency diffing, update batching, and keyed reconciliation — each as a runnable exercise.

Hooks from scratch
Rendering and reconciliation

We’re preparing the lessons and test cases. This track will open soon.

Track 05

Node.js

javascript Coming soon

Backend building blocks you can actually execute: stream parsing, aggregation, rate limiting, caching, and routing.

Streams and data
Server patterns

We’re preparing the lessons and test cases. This track will open soon.

Track 06

System Design

javascript Coming soon

Design questions with the hand-waving removed: implement the mechanism at the centre of each answer — short codes, hashing rings, limiters, fan-out and eviction.

Core mechanisms
Scale and delivery

We’re preparing the lessons and test cases. This track will open soon.