Senior Backend Engineer (Ruby), Plan: Spec-Driven Development

Location: Remote, Poland; Remote, United Kingdom

Department: DevOps Engineering

An overview of this role

As a Senior Backend Engineer on the Plan: Spec-Driven Development team, youll help build GitLabs intent-to-code loop: agentic workflows that turn a stated intent into a refined work item, an implementation plan, and verified, mergeable code. Youll own early-stage backend work across the flows, application programming interfaces, data models, and evaluation systems behind this experience, using Ruby on Rails, Python, PostgreSQL, GitLab Duo Agent Platform, large language model application programming interfaces, and an artificial intelligence gateway.

Youll join a small, distributed team working on one of GitLabs highest-visibility product bets, collaborating with design partners toward a public beta. In your first year, youll lead major features from an unclear problem through release, help shape scope with product and users, mentor other engineers, and influence technical decisions across agent workflows and evaluation methods.

What you’ll do

• Lead backend features from early product discussions through technical design, implementation, rollout, and post-launch learning.
• Build the flows, application programming interfaces, and data models behind agent-generated work items, implementation plans, durable specifications, and mergeable code.
• Develop evaluation and benchmarking systems that measure workflow quality, token cost, and success rate.
• Use Ruby on Rails and Python to build reliable production systems, with PostgreSQL, GraphQL, representational state transfer, GitLab Duo Agent Platform, large language model application programming interfaces, and an artificial intelligence gateway.
• Collaborate directly with product, design, engineers, design partners, and users to shape scope and make practical trade-offs.
• Coordinate multi-person projects across the team and communicate decisions clearly in GitLabs asynchronous, all-remote environment.
• Mentor other engineers and contribute to technical direction across the Plan group and related artificial intelligence initiatives.
• Work in short iterations, share progress through demos, and use results and user feedback to guide what comes next.

What you’ll bring

• Strong Ruby on Rails experience in a large production codebase and production experience with Python.
• Experience driving substantial projects with several engineers over multiple months, with clear user or business outcomes.
• A product mindset and experience owning features end to end, including shaping scope, making trade-offs, engaging with users, and learning from adoption after launch.
• A full stack background with a current focus on backend engineering, plus the ability to read modern frontend code and design effective APIs.
• Strong application programming interface design and structured query language fundamentals.
• Experience exploring artificial intelligence-assisted development.
• The ability to work independently, collaborate across functions and regions, and support others through technical leadership and mentoring. Experience with GraphQL, PostgreSQL performance at scale, or building and evaluating large language model or agent systems is helpful but not required.

We welcome candidates with different backgrounds and transferable experience. If youre excited about the role but dont meet every qualification, we encourage you to apply.

About the team

We are a team of four engineers, with two backend and two frontend engineers across Canada and Europe. Youll work in an all-remote, async-first environment with weekly sync calls, retrospectives, demos, and short iterations. This is early-stage work with broad ownership, space for creativity, and a fast pace. For more about our team and its work, see Plan Team Handbook Page and Spec-Driven Development Initiative