Millennium interview process (2026)

Round-by-round breakdown of the Millennium software engineering interview across 3 levels and 16 rounds: interview mode, sample questions, and worked solutions.

Millennium salary & ratings · All interview processes

Software Engineer (Bengaluru)

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

  1. Round 0: Recruiter screen

    Phone · ~30 min

    Mode of interview: Remote phone or video interview

  2. Round 1: HackerRank online test

    Assessment · ~2 hours · difficulty 2/5 · elimination round

    Mode of interview: Online assessment · HackerRank

    Sample question: A trade log contains N ticker symbols, one per line. Print the K most frequently traded symbols with their counts, most frequent first; break ties lexicographically. Input: N, then N symbols, then K. (Representative of the easy-medium coding slot; the same test carried SQL questions and AWS/Docker MCQs.)

  3. Round 2: Caliper cognitive + personality assessment

    Assessment · ~45-60 min · difficulty 1/5 · elimination round

    Mode of interview: Online assessment

  4. Round 3: Onsite: DSA + core CS fundamentals

    Onsite · ~45-60 min · difficulty 3/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: You are given N time intervals [start, end]. Merge all overlapping intervals and print the merged list sorted by start. Input: N, then N pairs. (Merge Intervals -- reported verbatim from a June 2024 Bengaluru onsite.)

  5. Round 4: Onsite: practical engineering + resume deep-dive

    Onsite · ~60 min · difficulty 3/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Given a trades table (symbol, ts, side, qty, price), write SQL to return each symbol's daily VWAP (sum of qty*price over sum of qty) for the last 30 days, excluding symbols with fewer than 100 trades that day. Follow-up: how does your query behave on a 2-billion-row table, and what index or partitioning would you add?

  6. Round 5: Hiring manager + behavioral round

    Behavioral · ~45 min · difficulty 2/5

    Mode of interview: Live behavioral interview

Quantitative Developer (C++)

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

  1. Round 0: Recruiter / pod screen

    Phone · ~30 min

    Mode of interview: Remote phone or video interview

  2. Round 1: C++ deep-dive + coding round

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

    Mode of interview: Onsite or virtual onsite interview

    Sample question: A market-data feed delivers N price ticks. For every window of the last K ticks, output the maximum price in O(N) total, not O(N*K). Follow-ups: why a monotonic deque beats a multiset here, what its worst-case allocation behaviour is, and how you would handle out-of-order ticks.

  3. Round 2: Probability + quantitative reasoning

    Onsite · ~45 min · difficulty 4/5

    Mode of interview: Onsite or virtual onsite interview

    Sample question: An urn has 5 red and 3 blue balls. You draw two without replacement and the first is red -- what is the probability the second is also red? (Asked in a Bengaluru Millennium round.) Follow-up: you roll a fair die and are paid the face value, but may re-roll once -- what is the fair price of this game?

  4. Round 3: Low-latency systems design

    System_design · ~60 min · difficulty 4/5

    Mode of interview: Live system design interview

    Sample question: Design a feed handler that consumes a multicast exchange feed, normalises ticks and fans them out to strategy processes on the same host. Cover threading model, queueing between stages, what happens when a strategy consumer stalls, and how you detect and recover sequence gaps.

  5. Round 4: Pod fit + manager round

    Behavioral · ~45 min · difficulty 2/5

    Mode of interview: Live behavioral interview

Senior Software Engineer

Difficulty: Hard · Timeline: ~4-6 weeks · Recommended prep: 6-8 weeks

  1. Round 0: Recruiter + hiring manager screen

    Phone · ~45 min · difficulty 1/5

    Mode of interview: Remote phone or video interview

  2. Round 1: Technical screen: coding + fundamentals

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

    Mode of interview: Onsite or virtual onsite interview

    Sample question: Implement a thread-safe LRU cache with get/put in O(1), then discuss: where does a single global lock hurt, how would you shard it, and what changes if values are large and eviction must not block readers?

  3. Round 2: Architecture: data platform design

    System_design · ~60-75 min · difficulty 4/5

    Mode of interview: Live system design interview

    Sample question: Design a market-data and vendor-data platform for quantitative research: ingestion, validation, versioning, and point-in-time ("as-of") query support for researchers. A vendor restates 3 months of history -- walk through exactly what happens in your design and how yesterday's backtest remains reproducible.

  4. Round 3: Project deep-dive + backlog scenario

    Onsite · ~60 min · difficulty 3/5

    Mode of interview: Onsite or virtual onsite interview

  5. Round 4: Senior management round

    Behavioral · ~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.