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SysRound

Practice the system design round out loud.

Talk through a real problem with an AI interviewer who listens, asks follow-ups and draws with you on a shared whiteboard. You leave with a hire or no-hire call for your level and a plan for what to practice next.

Start a free roundSee a sample scorecard

Mid-level to staff. Rounds of 30, 45 or 60 minutes. Free during the beta.

Alex, your interviewerSay one link goes viral: a million clicks in an hour on a single code. What breaks first?

What 45 minutes with Alex sounds like

Every round follows the structure big tech interviewers use, with time set aside for each part. Here is one, minute by minute.

  1. 00:40
    Requirements

    AlexBefore you draw anything, what would you like to know?

    YouHow many new links a day, and how many clicks per link? And do links ever expire?

  2. 09:12
    High-level design

    AlexWalk me through what happens when someone opens a short link.

    YouThe API looks the code up in Redis, falls back to Postgres on a miss, and returns a 302.

  3. 27:30
    Deep dive

    AlexSay one link goes viral: a million clicks in an hour on one code. What breaks first?

    YouThat key lives on a single Redis node, so I'd keep the hottest codes in memory on every server.

  4. 45:00
    Scorecard

    AlexThanks so much, that was a fun one. Your feedback is coming right up.

    ThenTwo minutes later: a verdict for senior, the moments behind it, and what to practice next.

Feedback you can act on

Every score cites what you said or drew. You see the moments that decided the call, what to say instead, and the issues in your final design.

  • A verdict for the level you're targeting, with how confident it is.
  • “You said this, say this instead”, for the moments that mattered.
  • A model answer and a reference diagram to compare with your board.
  • A practice plan that targets the gaps behind the verdict.

Sample from a practice round

URL shortener, senior (L5/E5)

No hireWould be hire at mid-level
Problem framing & requirements
Navigation & ownership
High-level architecture
Technical depth
Trade-offs & judgment
Scale, reliability & operations
Communication & collaboration
You said

“The cache handles it, Redis is fast.”

Say this instead

“One key on one Redis node tops out around 100k reads a second, so I'd keep the hottest codes in a small local cache on each server and let the CDN serve redirects.”

Questions asked in real onsites

Each comes with a private interviewer spec: scope, numbers, deep dives and the bar for your level. Pick one, or let your resume choose.

  • URL shortener

    Read-heavy key-value service: unique short-code generation, hot-key caching, redirect semantics.

    Mid and senior, medium difficulty

    Practice this

  • Distributed rate limiter

    Algorithm trade-offs (fixed window, sliding log, sliding counter, token bucket), placement, distributed atomic counting, failure modes.

    Mid to staff, medium difficulty

    Practice this

  • Notification system

    Async processing with durable queues, per-channel isolation, retries/DLQ, at-least-once + idempotency, outbox, priorities.

    Mid to staff, medium difficulty

    Practice this

  • News feed

    Fan-out on write vs read, celebrity hybrid, feed caches, outbox, ranking as an extension.

    Mid to staff, hard difficulty

    Practice this

  • Chat / messaging app

    Stateful connections, routing between chat servers, offline delivery, receipts, ordering, group fan-out, media via object storage.

    Senior and staff, hard difficulty

    Practice this

  • Ticket booking (Ticketmaster)

    Contention on scarce inventory: seat holds with TTL, locking/optimistic concurrency, payments, flash-sale traffic and virtual queues.

    Senior and staff, hard difficulty

    Practice this

  • Video streaming (YouTube)

    Upload pipeline, transcoding DAG, adaptive bitrate streaming, CDN economics, metadata and view counts.

    Senior and staff, hard difficulty

    Practice this

  • Ride hailing (Uber)

    High-frequency location updates, geospatial indexing, matching with contention, trip state machine.

    Senior and staff, hard difficulty

    Practice this

  • Web crawler

    URL frontier, politeness, deduplication at scale, distributed workers, failure and trap handling.

    Mid to staff, medium difficulty

    Practice this

Coming next: AI system design rounds, including LLM serving, RAG search and agent platforms.

Built to feel like the real thing

An interviewer, not a chatbot
Alex is warm, keeps you talking and asks one question at a time. It never hands you the answer, just like the people you'll meet onsite.
Talk the way you would on a call
Full-duplex voice means you can cut in any time. Press Pause to think when you want silence while you draw.
It reads your board and notes
Your diagram and notes are shared live, so follow-ups are about the design you drew, not a generic one.
A verdict you can check
Every score cites your own words. Fixed rules turn scores into the call, so the same evidence always gets the same result.

Questions people ask first

Is it free?

Yes, during the beta. Each account can run a few rounds a day. You need an account so your scorecards stay private to you.

How is the hire or no-hire call made?

A grader scores seven dimensions, such as requirements, high-level design, depth and trade-offs, citing what you said and drew. Then fixed rules decide the verdict for your level, counting any hints you needed. You can see the reasoning on every scorecard.

Which levels does it cover?

Mid-level (L4/E4), senior (L5/E5) and staff (L6+/E6+). The bar, the deep dives and how much the interviewer leads all change with the level you pick.

Does it cover AI and ML system design?

Classic system design is live now. AI system design rounds, such as LLM serving, RAG search and agent platforms, are next.

What happens to my audio?

Your audio is transcribed for grading and then discarded. Transcripts, whiteboards and scorecards are private to your account.

Can I use it to interview candidates?

No. SysRound is for your own practice. Using it to make hiring decisions about other people isn't allowed.

Walk into your onsite having done the round before.

Start a free round