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  • Company-specific rubrics for coding, system design, and behavioral

Design a Rate Limiter

MEDIUM

Design and implement a rate limiter that can handle millions of requests. Support multiple algorithms: token bucket, sliding window, fixed window. Consider distributed systems.

04:43 / 45:00
You

Should I consider distributed rate limiting?

Interviewer

Great question! Yes, let’s design this for a distributed system. Think about how you’d handle synchronization across multiple nodes and what trade-offs you’d make…

Python
class RateLimiter:    def __init__(self, max_requests: int, window_seconds: int):        self.max_requests = max_requests        self.window_seconds = window_seconds        self.requests = {}        self.lock = threading.Lock()     def is_allowed(self, client_id: str) -> bool:        current_time = time.time()        window_start = current_time - self.window_seconds         with self.lock:            # Clean old requests            self.requests[client_id] = [                t for t in self.requests.get(client_id, [])                if t > window_start            ]

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    30 mock interviews here prepared me for the real thing. Landed Netflix with a 100% TC increase.

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  1. 01

    Choose Your Target Company

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  2. 02

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  3. 03

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Medium

Two Sum

Python
def twoSum(nums, target):    seen = {}    for i, num in enumerate(nums):        diff = target - num        if diff in seen:            return [seen[diff], i]        seen[num] = i    return []

What's the time complexity of your solution? How would it handle duplicate values?

Coding Interview

1.1/5

Needs Work

  • Correctness1.2
  • Complexity1.1
  • Code Quality1.1
  • Communication1.2
  • Problem Solving1.1
012345CorrectnessComplexityCode QualityCommunicationImpactLeadershipArchitectureScalabilityTrade-offs

Built by Engineers Who've Been There

  • GoogleHard

    Stream Window Extraction

  • MetaHard

    Score Tracker Analysis

  • AmazonHard

    Top-K Variant

  • OpenAIEasy

    IP Iterator

  • AnthropicHard

    Computer Use Security

Google
  • Correctness
  • Complexity
  • Code Quality
  • Communication
  • Problem Solving
Meta
  • Correctness
  • Complexity
  • Code Quality
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  • Problem Solving
24/7
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How would this handle 10 million concurrent requests?

What's the trade-off?

  1. 04:43
    You

    Should I consider distributed rate limiting?

  2. 05:02
    Interviewer

    How would this handle 10 million concurrent requests?

  3. 05:21
    Interviewer

    What's the trade-off?

The Only Platform That Proves You're Improving

Watch your skills grow from first attempt to interview-ready. Our scoring system tracks 9 dimensions across coding, behavioral, and system design, so you know exactly when you're ready.

012345Strong Pass
Illustrative

Coding Interview

3.8/5

Strong Pass

  • Correctness4.1
  • Complexity3.6
  • Code Quality3.8
  • Communication3.9
  • Problem Solving3.6

Every Problem Comes Ready to Solve

Every coding question ships with starter code in 6 languages, reference example cases. Our Code Review checks your solution and flags gaps before an interviewer does.

def two_sum(nums, target):    seen = {}    for i, n in enumerate(nums):        if target - n in seen:            return [seen[target - n], i]        seen[n] = i

Test Cases

  • Input[2, 7, 11, 15], target = 9Output[0, 1]
  • Input[3, 2, 4], target = 6Output[1, 2]

Every round of the loop.

  1. 01

    Coding Interviews

    5,523+ problems with reference examples, starter code in 6 languages, and our Code Review that flags gaps in your solution

  2. 02

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  3. 03

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  4. 04

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  5. 05

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Better than other practice platforms

Compare with
FeaturePractice PlatformsPeer PlatformsOutside CoachesApex Interviewer
Real-time AI feedbackNoNoNoYes
Evaluates communicationNoYesYesYes
Company-specific rubricsNoNoNoYes
Behavioral + System DesignNoYesYesYes
Unlimited 24/7 practiceYesNoNoYes
Tracks improvementYesNoNoYes
Personalized feedbackNoNoYesYes
CostFreeFree$200+/session$100/month

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Questions, answered

How is this different from LeetCode or HackerRank?

Those platforms test if you can solve problems. We simulate the actual interview experience, with follow-up questions, communication evaluation, and company-specific rubrics. We also cover behavioral and system design interviews, not just coding.

Where do your interview questions come from?

Our questions are sourced from public forums, interview experience posts, and community contributions where engineers share their real interview experiences at top tech companies. We verify and curate these to ensure accuracy and relevance.

Can the AI really evaluate soft skills?

Yes. Our AI is trained on thousands of real tech interviews and can detect unclear explanations, missing trade-off discussions, and poor communication patterns. Every piece of feedback is grounded in your actual transcript.

What companies do you support?

Google, Apple, Amazon, Microsoft, Meta, Netflix, Oracle, TikTok, Uber, OpenAI, Anthropic, Perplexity, and xAI. We're adding more every month.

Do I need to schedule interview times?

Nope. Practice 24/7 whenever you want. The AI is always ready.

Does this work for senior/staff level interviews?

Yes. Our system design simulations and behavioral evaluations are calibrated for all levels from entry to staff engineer.

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