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

at GitLab

📍 Poland

PLN 272,000-408,000 per year

SENIOR

✅ Remote

Tech Stack
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3-6 — daily use. Comfortable and regular usage, capable of handling common tasks and challenges related to the technology;

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AI API @ 4 GraphQL @ 4 LLM Leadership @ 6 Mentoring @ 6 PostgreSQL @ 4 Python @ 4 Ruby @ 7 Ruby on Rails @ 7 SQL @ 7 Technical Leadership @ 6

Details

GitLab is building an intent-to-code loop: agentic workflows that turn stated intent into refined work items, implementation plans, and verified, mergeable code. As a Senior Backend Engineer on the Plan: Spec-Driven Development team, you will own backend work across the flows, APIs, data models, and evaluation systems behind this experience.

You will work with Ruby on Rails, Python, PostgreSQL, GitLab Duo Agent Platform, large language model APIs, and an artificial intelligence gateway. The team is distributed across Canada and Europe and operates in an all-remote, async-first environment.

Responsibilities

Lead backend features from early product discussions through technical design, implementation, rollout, and post-launch learning.
Build the flows, APIs, 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, REST, GitLab Duo Agent Platform, large language model APIs, and an artificial intelligence gateway.
Collaborate with product, design, engineers, design partners, and users to shape scope and make practical trade-offs.
Coordinate multi-person projects and communicate decisions clearly in an 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 future work.

Requirements

Strong Ruby on Rails experience in a large production codebase.
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 API design and SQL fundamentals.
Experience exploring artificial intelligence-assisted development.
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.

Team

The team consists of four engineers, including two backend and two frontend engineers across Canada and Europe. The team works 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.