Prepare for your Cloudflare system design interview

Edge networking and CDN architecture cases calibrated to Cloudflare’s globally distributed, security-first engineering culture.

Socratify AI

The Interview

What Cloudflare is looking for

System Design Interview

Distributed Network Systems Design

01Global Scale & PoP Architecture

02Cache Invalidation Strategy

03DDoS Mitigation Design

04Low-Latency Routing

Coding Interview

Technical Coding Round

01Network Protocol Implementation

02Algorithm Efficiency

03Concurrency & Threading

04Systems-Level Reasoning

Behavioral Interview

01Security-First Mindset

02Global Impact Thinking

03Mission-Driven Engineering

04Incident Response Judgment

Edge-first global architecture//Security & DDoS mitigation at scale//Sub-50ms global propagation design

Practice Library

Cloudflare exercises

Ready to ace your Cloudflare system design interview?

Prepare for your Cloudflare system design interview

Edge networking and CDN architecture cases calibrated to Cloudflare’s globally distributed, security-first engineering culture.

Socratify AI

The Interview

What Cloudflare is looking for

System Design Interview

Distributed Network Systems Design

01Global Scale & PoP Architecture

02Cache Invalidation Strategy

03DDoS Mitigation Design

04Low-Latency Routing

Coding Interview

Technical Coding Round

01Network Protocol Implementation

02Algorithm Efficiency

03Concurrency & Threading

04Systems-Level Reasoning

Behavioral Interview

01Security-First Mindset

02Global Impact Thinking

03Mission-Driven Engineering

04Incident Response Judgment

Edge-first global architecture//Security & DDoS mitigation at scale//Sub-50ms global propagation design

How It Works

Master Cloudflare System Design Interviews

Edge networking and CDN architecture cases, scored on Cloudflare’s engineering evaluation dimensions. · Click to expand

1Your System Design Goals

Distributed Systems Design

Practitioner

Scalability & Tradeoff Analysis

Practitioner

2System Design Case Prep

Design a globally consistent configuration propagation system for Cloudflare that pushes...

CASE INTERVIEWHard

Cloudflare

3Frameworks

Framework

Has the cache hit rate degraded significantly?

Is the eviction policy causing premature key expiry?

Cache hit rate dropped from 94% to 31% over 12 minutes

LRU eviction triggered on 8 of 12 shards — max memory 92% utilized

Are hotkey collisions concentrating load on single shards?

Top 3 product SKUs drive 67% of cache reads — all hash to shard 4

Shard 4 CPU at 98% while remaining 11 shards average 31%

Is replication lag causing stale reads from replicas?

Primary-replica replication lag elevated?

Replica lag: 4.2 seconds (normal: <50ms) — reads serving stale prices

Write throughput increased 280% post Black Friday campaign launch

Is read-your-writes consistency violated for session data?

23% of checkout sessions see cart quantity revert after update

Sticky sessions disabled in load balancer 48 hours ago

Is network partitioning or node failure degrading cluster health?

Are cluster nodes experiencing partial network partitions?

2 of 12 Redis nodes reporting intermittent timeouts (AZ-3 subnet)

AZ-3 network maintenance window started 18 minutes ago

4Feedback

Distributed Systems Design

Distinctive

Scalability Reasoning

Strong

Tradeoff Quantification

Meeting Bar

Architectural Communication

Strong

Repeat

Practice Library

Cloudflare exercises

Design Cloudflare’s global CDN cache invalidation system that propagates updates to 300...

CASE INTERVIEWHard

Networking & Security · System DesignCloudflare

Design Cloudflare Workers KV — a globally replicated key-value store with eventual...

LEARNHard

Networking & Security · System DesignCloudflare

Design a Layer 7 DDoS mitigation system for Cloudflare that filters 10 million malicious...

LEARNHard

Networking & Security · System DesignCloudflare

Tell me about a time you designed or improved a system that had to operate at global...

BEHAVIORALMedium

Behavioral · Security MindsetCloudflare

Describe a situation where you had to make a critical architecture decision under...

BEHAVIORALHard

Behavioral · Engineering JudgmentCloudflare