Senior

Build Reddit's LLM Gateway and GenAI platform infrastructure at scale

Interview for a Senior Software Engineer role on Reddit's Machine Learning Platform team, leading development of a large-scale GenAI Platform including an LLM Gateway with unified API endpoints, rate/token limiting, and failover. Expect deep questions on RAG systems, agentic workflows with LangChain/LangGraph, and LLMOps practices at Kubernetes scale.

Practice this interview

Free · a live voice mock calibrated to this exact role

Start the mock interview

What this interview tests

LLM Gateway design (unified endpoints, rate limiting, failover)
RAG systems (embeddings, vector search, retrieval pipelines)
Agentic workflows with LangChain/LangGraph
LLMOps/MLOps practices (CI/CD, versioning, evaluation, observability)
Kubernetes and infrastructure-as-code at scale (Terraform)
Platform thinking and cross-team enablement

Common question themes

Design an LLM Gateway with failover across multiple providers

Walk through a RAG pipeline you built and how you evaluated retrieval quality

Describe an agentic workflow you implemented with LangChain or LangGraph and a failure mode you hit

How do you operationalize LLMOps practices for a GenAI pipeline in production

How have you scaled ML infrastructure on Kubernetes with Terraform

How do you design a platform that other engineering teams can self-serve on

How candidates describe it

Real Senior Software Engineer interview stories — retold from candidates' public write-ups, with sources.

Bloomberg · Senior Software EngineerOffer

Bloomberg Senior Software Engineer Interview: Five Rounds, Offer

A Senior Software Engineer candidate applied to Bloomberg's London office through the company's careers site and, after an initial screen, went through five separate on-site conversations covering coding, system design, a recruiter chat, and a hiring-manager round, ultimately accepting an offer.

Interviewed October 2022 · London, United Kingdom

Google · L3 Software EngineerOffer

Google 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 offer

Google 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

View the original posting

All Reddit Senior Software Engineer interviews

All Reddit interviews