Intermediate Backend Engineer, Cells Infrastructure

An overview of this role

As an Intermediate Backend Engineer on GitLab's Cells Infrastructure team, you'll help build the architecture that lets GitLab.com scale horizontally. Cells splits GitLab.com into independent units, each with its own application and data stack, behind a shared routing layer.

You'll build the services and application changes that make Cells work: the control plane that tracks cells and organizations, the routing logic that sends each request to the right cell, and the changes inside the GitLab application that keep data unique and consistent across cells. Your work will directly support moving customer organizations onto Cells, one of GitLab's most important scaling initiatives.

You'll work across Go, Ruby on Rails, and TypeScript.

What you’ll do

• Design, build, and maintain the Cells control plane, a Go service using gRPC (remote procedure calls) and backed by Cloud Spanner that tracks cells, organizations, and globally unique resources.
• Extend the global routing layer, written in TypeScript on Cloudflare Workers, so requests reach the right cell. This includes classifying requests by path, namespace, and token, and supporting more protocols and services.
• Make changes in the GitLab Rails application so it works across multiple cells: claiming globally unique resources, propagating organization context, and keeping cell-local data consistent.
• Design application programming interfaces (APIs) and data models with correctness, idempotency, and backward compatibility in mind, so changes can roll out safely across a fleet of cells.
• Write thorough automated tests, including unit, integration, and end-to-end tests, and improve test coverage and reliability across the services we own.
• Instrument your services with OpenTelemetry for metrics, logs, and distributed tracing. Help define service level objectives (SLOs) and take part in on-call for the services you build.
• Work with product teams to make their features cell-compatible, and review their changes for Cells correctness.
• Write clear design documents, architecture decision records, and documentation, and take part in code review as both author and reviewer.

What you’ll bring

• Professional experience building and running backend services in production, including monitoring, debugging, and incident response. You've instrumented services with OpenTelemetry and used distributed tracing to debug requests across service boundaries.
• Proficiency in Go, or strong experience in another backend language and willingness to work in Go daily.
• Experience with Ruby on Rails and TypeScript, or the willingness to become productive in both. Our control plane is written in Go, the GitLab application in Rails, and our edge routing layer in TypeScript.
• Experience designing APIs using gRPC or Representational State Transfer (REST), and working with relational or distributed databases, including schema design, transactions, and migrations.
• A strong understanding of distributed-systems fundamentals, such as consistency, idempotency, concurrency, retries, and failure handling.
• Solid grounding in engineering best practices: test-driven development, small iterative merge requests, thorough code review, feature flags for safe rollouts, and observable, well-documented code.
• Experience working effectively in distributed, all-remote teams: you default to asynchronous, written-first communication, document decisions in issues and merge requests, hand off work cleanly across time zones, and stay transparent about progress and blockers.
• If you've worked with Cloud Spanner, Cloudflare Workers, Kubernetes, multi-tenant or sharded architectures, or contributed to GitLab, that's a plus, not a requirement.

About the team

The Cells Infrastructure team is part of GitLab's Scale & Architecture organization, which builds and operates the core services that let GitLab.com grow. Every team in the organization owns its services end to end, from design through on-call.

Beyond the control plane and routing services you'll help build, we're responsible for:

• Provisioning cells across Amazon Web Services (AWS) and Google Cloud.
• Ring-based deployments that keep the fleet in step with GitLab's release cadence.
• SLOs, alerting, and on-call for the platform.
• The infrastructure for moving customer organizations between cells.

Our team mixes Backend Engineers and Site Reliability Engineers who work side by side on the same services. We work closely with delivery, database, migration, and product teams across GitLab. Feature teams own how their services behave on the Cells platform.

We're an all-remote, asynchronous team. We make decisions in GitLab issues, use directly responsible individuals (DRIs) to own technical direction, demo our work weekly, and use artificial intelligence (AI)-assisted workflows every day.