// Round 02 · 45 min · 25 credits
Live coding.
Algorithms and data structures in an in-browser editor, while you explain your approach out loud.
Live coding is not a test of whether you can produce an answer. It’s a test of how you get there: whether you clarify the problem, pick an approach for a reason, communicate while you work, and catch your own bugs. Hardmode gives you an in-browser editor and an interviewer that watches the whole process, not just the final output.
Scope
What this round covers
- Clarifying inputs, constraints, and edge cases before writing code
- Choosing a data structure and saying why
- Talking through your approach while you implement it
- Testing your own code and reasoning about time and space complexity
Session
How the session runs
01 —
The problem
Pulled from the question bank, matched to the level and stack in the job description, or your own prompt.
02 —
Code in the editor
Write and run code in the browser. The interviewer can see the editor and hear your reasoning.
03 —
Follow-ups
Once it works, expect the twist: a new constraint, a larger input, or a request to optimise.
Personalised
Fitted to you
Your CV
Uses a language from your CV or the job, and pitches problems at the level you’re interviewing for. Optional, and you can switch it off for any session.
Your difficulty
- Easy: A friendly interviewer who wants you to do well.
- Medium: A fair, professional interviewer. What most interviews feel like.
- Hard: A proper grilling, like a big-tech bar-raiser loop.
Review
What your feedback covers
- How you used your time, from clarifying to testing
- Moments where explaining helped, and places where saying more would have
- Edge cases and complexity points worth revisiting, tied to the line in your code
Detailed and supportive at every difficulty · No score, no verdict
Prep
Tips before you start
- Restate the problem and confirm one example before touching the keyboard.
- Say the brute-force approach first; it buys time and shows judgement.
- Trace your code with a small input before declaring it done.
// Next round
The rest of the loop
// Player 1
Get ready for hard mode.
Paste the job you want. Run the loop until the real one feels like a rematch.
20 free credits · No card required