Cloudflare interview process (2026)

Round-by-round breakdown of the Cloudflare software engineering interview across 3 levels and 15 rounds: interview mode, sample questions, and worked solutions.

Cloudflare salary & ratings · All interview processes

Software Engineer Intern

Difficulty: Medium · Timeline: ~3-4 weeks · Recommended prep: 4-6 weeks

  1. Round 0: Application + AI-app fast-track and recruiter chat

    Phone · ~30 min

    Mode of interview: Remote phone or video interview

  2. Round 1: Online coding assessment (HackerRank)

    Assessment · ~60-90 min · difficulty 2/5 · elimination round

    Mode of interview: Online assessment · HackerRank

    Sample question: You are given N web-server access log lines of the form "<ip> <method> <path> <status>" and an integer K. Print the top K IP addresses by request count, one per line as "<ip> <count>", ordered by count descending, breaking ties lexicographically by IP. Input: first line N and K, then N log lines.

  3. Round 2: Technical interview: coding + CS fundamentals

    Onsite · ~60 min · difficulty 3/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Implement a function that takes a list of (domain, IP) pairs and answers lookups with wildcard support: a query "a.b.example.com" should fall back to "*.example.com" if no exact entry exists. Discuss complexity and how real DNS resolution differs.

  4. Round 3: Hiring manager + behavioral chat

    Behavioral · ~30 min · difficulty 1/5

    Mode of interview: Live behavioral interview

Software Engineer

Difficulty: Medium · Timeline: ~3-5 weeks · Recommended prep: 6-8 weeks · Cooldown: ~6 months

  1. Round 0: Recruiter screen

    Phone · ~30 min

    Mode of interview: Remote phone or video interview

  2. Round 1: Hiring manager screen

    Phone · 30-45 min · difficulty 2/5 · elimination round

    Mode of interview: Remote phone or video interview

    Sample question: Walk me through a system you built end-to-end. Follow-ups reported in India loops: how does DNS resolution work from stub resolver to authoritative server, and where do encryption keys live in a TLS termination path?

  3. Round 2: Technical screen: practical systems coding

    Phone · ~60 min · difficulty 3/5 · elimination round

    Mode of interview: Live interview · CoderPad

    Sample question: Implement a per-client sliding-window rate limiter: given W (window seconds) and L (max requests), process N requests as (client_id, timestamp) in non-decreasing time order and print ALLOW or DENY for each. Only allowed requests count toward the window. Input: first line N W L, then N lines "client ts".

  4. Round 3: Onsite coding: build + debug (AI-assisted for some teams)

    Onsite · ~60 min · difficulty 4/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Extend an LRU cache with per-entry TTL (edge-cache semantics): capacity C, operations PUT key value ttl ts and GET key ts. GET returns -1 if the key is absent or expired (lazily evict expired entries); both PUT and GET refresh recency. Print each GET result. Input: first line C Q, then Q operation lines.

  5. Round 4: System design: edge-scale, no managed cloud

    System_design · ~60 min · difficulty 4/5

    Mode of interview: Live system design interview

    Sample question: Design the log pipeline for a CDN with 300+ edge PoPs: every HTTP request generates a log line; customers need near-real-time analytics and 30-day retention. You may not use any managed cloud service. Cover transport from PoPs, backpressure when a region is cut off, aggregation, and the storage engine choice.

  6. Round 5: Behavioral ("Orange Cloud") round

    Behavioral · ~30 min · difficulty 2/5

    Mode of interview: Live behavioral interview

Senior Software Engineer

Difficulty: Hard · Timeline: ~4-6 weeks · Recommended prep: 8-10 weeks · Cooldown: ~6-12 months

  1. Round 0: Recruiter + hiring manager screens

    Phone · 2 x 30-45 min · difficulty 1/5 · elimination round

    Mode of interview: Remote phone or video interview

  2. Round 1: Technical screen: systems coding

    Phone · ~60 min · difficulty 4/5 · elimination round

    Mode of interview: Remote phone or video interview

    Sample question: Implement a token-bucket rate limiter supporting burst capacity B and refill rate R tokens/sec, then make it safe for concurrent callers. Follow-ups: memory for 10 million client buckets, lazy refill vs a background ticker, and how you would shard state across proxy processes on one edge server.

  3. Round 2: System design deep dive: global edge infrastructure

    System_design · 60-75 min · difficulty 5/5

    Mode of interview: Live system design interview

    Sample question: Design Cloudflare KV: a key-value store readable from 300+ PoPs with p99 read latency under 10 ms worldwide, writes accepted centrally, and eventual global propagation. No managed cloud services. Cover replication topology, cache invalidation vs TTL trade-offs, cold-key reads from a far PoP, and what a network partition between a PoP and core does to reads and writes.

  4. Round 3: Architecture retrospective: your system, deep-dived

    Onsite · ~60 min · difficulty 4/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Take the highest-scale system you have owned. Reported follow-up pattern: where exactly does a request enter, what is the p99 budget per hop, what failed in your worst incident, and what would you redesign today - then "how would this design change running in 300 PoPs instead of 3 regions?"

  5. Round 4: Behavioral + leadership ("Orange Cloud")

    Behavioral · 30-45 min · difficulty 2/5

    Mode of interview: Live behavioral interview

Other companies' interview processes

Worked sample solutions (code, design diagrams, and STAR answers) for every round are available in the FAANGPlus app: open interview processes.