Reddit prep

Reddit Mid-level (3–5 years) System design

#16

Design a distributed rate limiter for an API gateway — Reddit interview

Reported in Reddit USA engineering loops. System design testing token bucket, sliding window, and Redis coordination.

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Reddit Senior (5–8 years) System design

#17

Design a real-time chat application like Slack or WhatsApp — Reddit interview

Reported in Reddit USA engineering loops. Mid-to-senior design spanning WebSockets, message storage, and presence.

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Reddit Senior (5–8 years) System design

#18

Compare cache-aside, read-through, write-through, and write-back — Reddit interview

Reported in Reddit USA engineering loops. Caching patterns for system design and backend performance tuning.

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Reddit Senior (5–8 years) System design

#19

How does a load balancer work and which algorithms would you choose? — Reddit interview

Reported in Reddit USA engineering loops. Infrastructure design question covering L4/L7 balancers and health checks.

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Reddit Mid-level (3–5 years) Behavioral

#20

Tell me about a time you disagreed with a teammate. How did you handle it? — Reddit interview

Reported in Reddit USA engineering loops. Behavioral STAR question assessing collaboration and conflict resolution.

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Reddit Lead / Staff (8+ years) Behavioral

#21

Describe a time you led a project or initiative without formal authority — Reddit interview

Reported in Reddit USA engineering loops. Leadership behavioral question for senior and lead engineering tracks.

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Reddit Lead / Staff (8+ years) Manager / leadership

#22

How do you mentor junior engineers on your team? — Reddit interview

Reported in Reddit USA engineering loops. Managerial and lead-round question on coaching, feedback, and growth.

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Reddit Junior (1–3 years) HR / screening

#23

What are your salary expectations? — Reddit interview

Reported in Reddit USA engineering loops. HR negotiation question requiring research and flexible framing.

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Reddit Mid-level (3–5 years) Technical deep dive

#24

What principles do you follow when designing RESTful APIs? — Reddit interview

Reported in Reddit USA engineering loops. API design question covering resources, HTTP semantics, and versioning.

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Reddit Mid-level (3–5 years) Technical deep dive

#25

When would you choose microservices over a monolith? — Reddit interview

Reported in Reddit USA engineering loops. Architecture trade-off question for mid-level backend and platform roles.

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Reddit Mid-level (3–5 years) Technical deep dive

#26

Explain CI/CD and what a typical pipeline includes — Reddit interview

Reported in Reddit USA engineering loops. DevOps fundamentals for mid-level engineers discussing automation and quality gates.

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Reddit Mid-level (3–5 years) Technical deep dive

#27

What is the difference between unit and integration tests? — Reddit interview

Reported in Reddit USA engineering loops. Testing strategy question covering pyramid, mocks, and confidence vs speed.

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Reddit Mid-level (3–5 years) Technical deep dive

#28

How does HashMap work internally in Java? — Reddit interview

Reported in Reddit USA engineering loops. Java-specific collections question on buckets, hashing, and resize behavior.

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Reddit Mid-level (3–5 years) Technical deep dive

#29

Explain the JavaScript event loop, call stack, and task queues — Reddit interview

Reported in Reddit USA engineering loops. Core JavaScript concurrency model question for frontend and Node.js roles.

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Reddit Mid-level (3–5 years) Technical deep dive

#30

What is the Python GIL and how does it affect concurrency? — Reddit interview

Reported in Reddit USA engineering loops. Python-specific question on threading limits and multiprocessing alternatives.

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