
Robinhood
Mid
ML engineer on Robinhood's AI Research and Development team building ranking, recommendation, and bandit-driven decision systems
This Bellevue, WA-based (3 days/week in office) Machine Learning Engineer role sits on Robinhood's AI Research and Development team, focused on ranking/recommendation model development, reinforcement learning and multi-armed bandit strategies, and rigorous A/B testing. The JD asks for a Bachelor's + 3 years (or Master's + 1 year) with hands-on production experience in classical and sequential-data ML, plus Python/SQL/XGBoost/PyTorch or TensorFlow and distributed systems tools (Spark, Kafka, Kubernetes). Expect questions on production model development, experimentation rigor, and cross-functional delivery despite the JD's senior-sounding language about mentoring and shaping vision.
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What this interview tests
- Ranking and recommendation systems (collaborative/content-based/hybrid filtering, LTR)
- Reinforcement learning and multi-armed bandit strategies
- A/B test design, execution, and statistical analysis
- Classical ML on tabular data and modern ML on sequential data
- Distributed, high-scale ML infrastructure (Spark, Kafka, Kubernetes)
- Cross-functional delivery with data scientists, engineers, and marketing
Common question themes
Design a ranking or recommendation model for a fintech product surface
Explain how you'd apply a multi-armed bandit to a live decision-making problem
Walk through an A/B test you designed end-to-end, including how you validated significance
Compare classical tabular ML techniques vs modern sequential-data approaches you've used
How would you scale a training/inference pipeline using Spark, Kafka, or Kubernetes
Describe a reusable ML library or tool you built and how others adopted it
How candidates describe it
Real Machine Learning Engineer interview stories — retold from candidates' public write-ups, with sources.
Google · L5 Machine Learning EngineerOfferGoogle L5 machine learning engineer interview: phone screen skipped, four technical rounds, and an offer
A candidate applying for an L5 machine learning engineer role at Google had the phone screen skipped due to a referral and prior tenure at the company, then went through four technical and design rounds plus a behavioral round before receiving an L5 offer. The loop was one leg of a broader search that produced offers from several companies in the same cycle.
Interviewed April 2022 · Remote
Amazon · Applied Scientist (L4)OfferAmazon Applied Scientist Interview Experience: Alexa Speech Team, 2021
A redirected recruiter call turned into an Amazon Applied Scientist loop with the Alexa Speech team: a phone screen, a split five-round virtual onsite across two teams, a bar raiser, and an added ML-breadth round, ending in an offer with a downlevel from L5 to L4.
Interviewed July 2021 · Boston, MA (Remote)
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