
Netflix
Senior
Build the infrastructure that trains, aligns, and serves Netflix's most critical ML models
Netflix's Model Runtime team owns the systems behind training, alignment, and serving of Netflix's core ML models, spanning RL-based post-training, distributed training at scale, and next-gen GenAI inference. This role sits at the intersection of systems engineering and ML, working across the stack from PyTorch internals down to GPU kernels.
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What this interview tests
- Distributed training systems (FSDP, tensor/pipeline/context parallelism)
- RL-based post-training infra (GRPO, DPO, PPO, reward modeling)
- GPU performance profiling and optimization (CUDA, NCCL, Nsight, PyTorch profiler)
- Inference optimization (vLLM, TensorRT, quantization, KV-cache, continuous batching)
- Multimodal/diffusion model serving and generation pipelines
- Operational excellence: observability, logging, on-call for ML infra
Common question themes
Design a fault-tolerant distributed training system across hundreds of GPUs
How would you build RL/DPO-style post-training infra for a recommendation model
Describe a time you profiled and optimized a training or inference workload from framework down to kernel level
How do you evaluate new hardware/accelerators or frameworks for an ML infra stack
Trade-offs between real-time, near-real-time, and batch inference for GenAI workloads
How do you operate a small, highly autonomous infra team with outsized impact
How candidates describe it
Real Software Engineer 5 – Model Runtime interview stories — retold from candidates' public write-ups, with sources.
Google · L3 Software EngineerOfferGoogle L3 software engineer interview: phone screen, four coding rounds, and the Googleyness round
A candidate with two years of experience went from recruiter outreach to offer over about four months. The onsite was four 45-minute coding rounds — three of them featuring binary trees — and one round turned into a 25-minute chain of follow-ups about approximating an optimal solution at scale.
Interviewed June 2020 · Bangalore, IN
Google · L4 Software EngineerNo offerGoogle L4 Software Engineer Interview: Eight Rounds, No Offer
An L4 Software Engineer candidate went through two phone screens, three onsite rounds, a culture conversation, and a team-matching call with a Google hiring manager, then watched the process stall for about a month and a half over a tightened experience requirement before an added extended round ended without an offer.
Interviewed February 2024 · Not specified
Google · L5 Software EngineerNo offerGoogle L5 software engineer interview: phone screening, three onsite rounds, system design, and a late rejection
A candidate interviewing for an L5 role went through a phone screening, three onsite coding rounds, a mobile system design round, and a Googleyness and Leadership round. Two of the four technical rounds went poorly by the candidate's own assessment, and after roughly two months of silence the recruiter reported that the role had been closed.
Interviewed January 2023 · Not specified
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