Build the backend that lets AI agents act on GitLab's MCP server and Duo Agent Platform

GitLab's Agent Tools team is hiring a senior backend engineer to design how AI agents interact with GitLab beyond code generation, centered on GitLab's MCP server. The interview will focus on production Ruby on Rails experience, REST/GraphQL API design, and judgment about safely shipping AI-powered backend features.

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What this interview tests

Production Ruby on Rails backend development
REST and GraphQL API design for scalability and backward compatibility
Designing safe, well-scoped interfaces for AI agents to call (MCP server context)
Testing discipline (RSpec) and observability/on-call
Judgment on LLM limitations in production backend features
Cross-functional collaboration with Product, UX, and AI specialists

Common question themes

Walk through a production Rails feature you owned end to end

How would you design a GraphQL or REST endpoint for an AI agent to safely call

What guardrails do you put around an AI agent acting on production data

Describe a performance bottleneck you diagnosed and fixed

How do you approach backward compatibility when evolving an API

Tell me about an on-call incident and your root-cause process

How candidates describe it

Real Senior Backend Engineer (Ruby) interview stories — retold from candidates' public write-ups, with sources.

Google · Backend Software EngineerNo offer

Google Backend Engineer Interview Experience: Bangalore Onsite (Rejected)

A rejected Google Backend Engineer candidate in Bangalore recounts a recruiter screen, a gating elimination round, and a three-round onsite loop covering trees, tries, scheduling, and graph problems.

Interviewed April 2021 · Bangalore, India

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

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