Coding sandbox and assessments

Real code, real tests, in the same tab.

Candidates write and run code against your test suite. You see the diff, the runtime, and what they did between keystrokes — not just whether it went green.

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Coding sandbox and assessments

Real code, real tests, in the same tab.

Candidates write and run code against your test suite. You see the diff, the runtime, and what they did between keystrokes.

  • Real runtimes

    Python, JavaScript, Java, Go, C and C++, with the standard library available.

  • Question bank or your own

    Vetted tasks per role and seniority, or paste in the problem your team actually cares about.

  • Anti-cheat that shows its work

    Paste bursts, tab blur, keystroke rhythm and full replay, flagged with timestamps rather than a verdict.

  • Non-engineering assessments

    Spreadsheet, writing, support-reply and sales-call tasks, scored on the same scale.

rate_limiter.golimiter_test.goGo 1.22 · 8 min left
01  func (l *Limiter) Allow(key string) bool {
02    now := time.Now()
03    l.mu.Lock()
04   defer l.mu.Unlock()
05   
06    b, ok := l.buckets[key]
07   if !ok {
08      b = &bucket{tokens: l.burst, last: now}
09      l.buckets[key] = b
10    }
11   // refill before spending
12    b.tokens = min(l.burst, b.tokens+l.rate*now.Sub(b.last).Seconds())
13    b.last = now
14   if b.tokens < 1 { return false }
15    b.tokens--
16   return true
17  }

Run output

PASS  TestAllow_Burst    0.00s

PASS  TestAllow_Refill   0.31s

PASS  TestAllow_Concurrent 0.04s

ok    limiter   14/14  41ms

Tab blur 0Paste 1 (32ch)Replay 41m

How it works

Set the task, read the evidence.

  1. Step 01

    Choose or paste a task

    Vetted tasks per role and seniority, or your own problem with your own tests. Set the runtime, the time limit and whether assistants are allowed.

  2. Step 02

    They code in the browser

    A real sandbox with the standard library available. They run the tests as often as they like and see exactly what you will see.

  3. Step 03

    You read the replay

    Tests passed, runtime, the diff, and a replay of how the solution was arrived at. Flags for paste bursts and tab blur sit alongside it, timestamped.

What you get

The process, not just the result.

  • Real runtimes

    Python, JavaScript, Java, Go, C and C++, with the standard library available.

  • Your tests, your bar

    Hidden tests, visible tests, or both. Candidates see the ones you want them to see, and the report shows every case with its result.

  • Anti-cheat that shows its work

    Paste bursts, tab blur, keystroke rhythm and a full replay — flagged with timestamps rather than reduced to a verdict you cannot inspect.

  • Non-engineering assessments

    Spreadsheet, writing, support-reply and sales-call tasks, scored on the same scale so the shortlist is comparable across functions.

  • Feeds the same report

    The coding result is a section of the candidate report, next to the AI interview and the panel scorecards, weighted by your rubric.

  • Accessible by default

    Keyboard-only navigation, screen-reader labels on the editor chrome, adjustable time for candidates who request it.

Questions about coding assessments

Can candidates use an AI assistant?
You decide per task. Where it is allowed, that is recorded on the report. Where it is not, paste bursts and keystroke rhythm are flagged with timestamps and the full replay is there for you to judge — we flag, we do not accuse.
Do you use the same puzzle for everyone?
Only if you want to. The bank has vetted tasks per role and seniority, and you can paste in the problem your team actually cares about — a bug from your own tracker usually beats a puzzle.
What about roles that do not write code?
Spreadsheet, writing, support-reply and sales-call tasks run in the same flow and score on the same scale, so a sales hire and an engineer are comparable on the same report.
How long should a task be?
Thirty to forty-five minutes is where completion rates hold up. The sandbox shows candidates the remaining time and saves continuously, so a closed tab does not lose the work.

Keep reading

Get started

Stop guessing from a CV whether they can build it.

Set one task, read the replay, and know before the first call.

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