ByteRooms

Low level design

Low level design interview practice with real people

Most LLD preparation is solitary: you read someone else's parking-lot solution and hope it sticks. Real interviews are a conversation — you clarify requirements, defend class boundaries, and adjust when the interviewer adds a constraint. ByteRooms recreates that: create a room, share a 5-character code, and design alongside 2-4 other developers.

Start a practice room

How a session works

  1. 1. Create a room. Pick LLD, HLD or mixed, choose a problem or take a random one, and set a timer.
  2. 2. Clarify together. Use room chat to agree on scope and constraints before touching code — the same first five minutes as a real interview.
  3. 3. Design on your own. Everyone writes their own class design in the editor (Java, Python, C++, TypeScript or C#) and can read each other's work.
  4. 4. Submit for review. An AI reviewer scores your design and explains what an interviewer would push on next.

Low level design questions in the library

  • Parking Lot

    Vehicle types, spot allocation, pricing strategy.

  • Chess

    Board, piece movement rules, game state, undo.

  • Elevator System

    Scheduling, request queues, direction state.

  • Vending Machine

    State machine, inventory, coin handling.

  • Movie Ticket Booking

    Seat locking, concurrency, payments.

  • Logging Framework

    Appenders, levels, extensibility.

Plus HLD problems — URL shortener, chat system, notification service, rate limiter and news feed — when you want to practise at system scale.

What the AI review looks at

Requirement coverage
Whether your classes actually satisfy every stated requirement.
OOP modelling
Class responsibilities, encapsulation, and relationships.
SOLID
Single responsibility, open/closed, and dependency direction.
Design patterns
Where a strategy, factory, or state pattern fits — and where it doesn't.
Extensibility
How your design absorbs the follow-up questions interviewers ask.

Practice with a group, not alone

Rooms hold up to four developers, so a study group can run one problem per sitting and compare designs afterwards. Signal when you're stuck, credit whoever unblocked you, and build a streak with the daily challenge. No account is required to start — sign in with Google only if you want your progress to follow you across devices.

Create a room