About Codejump

Why it exists

Most interview preparation optimises for the wrong thing. Abstract puzzle sites train you for a contest; tutorial courses train you to follow along. Neither resembles the hour you actually spend in front of an interviewer, being asked to debounce a function, flatten a structure, reason about a race condition or explain why a query is slow.

Codejump is built around that hour. Every challenge is a problem that gets asked, the way it gets asked, with tests that decide whether your answer works.

How it works

You write your solution in the browser and submit it. The code runs in an isolated sandbox against the same test cases the challenge was designed with — the public ones you can see, and hidden ones you cannot — and you get back a pass or fail per test, not a similarity score against a reference answer.

Around the challenges sit quizzes for the theory that gets asked out loud, learning paths that sequence the material, guided projects, and mock interviews.

What you can practise

JavaScript, TypeScript, React, Vue, Angular, Node.js, Python and SQL — several hundred challenges and several hundred quizzes, with most exercises available in more than one language so the same problem can be solved the way you would solve it at work.

Free and Pro

A large part of the catalog is free and stays free, with no time limit. Pro unlocks the rest along with the AI mentor and the mock-interview flow. The pricing page has the details.

Contact

Questions, bug reports and content suggestions are welcome at hello@codejump.io. Billing questions go to support@codejump.io.