Intermediate Backend Engineer (Ruby), AI Engineering, Custom Models

GitLab is an open-core software company that develops the most comprehensive AI-powered DevSecOps Platform, used by more than 100,000 organizations. Our mission is to enable everyone to contribute to and co-create the software that powers our world. When everyone can contribute, consumers become contributors, significantly accelerating human progress. Our platform unites teams and organizations, breaking down barriers and redefining what's possible in software development. Thanks to products like Duo Enterprise and Duo Agent Platform, customers get AI benefits at every stage of the SDLC.

The same principles built into our products are reflected in how our team works: we embrace AI as a core productivity multiplier, with all team members expected to incorporate AI into their daily workflows to drive efficiency, innovation, and impact. GitLab is where careers accelerate, innovation flourishes, and every voice is valued. Our high-performance culture is driven by our values and continuous knowledge exchange, enabling our team members to reach their full potential while collaborating with industry leaders to solve complex problems. Co-create the future with us as we build technology that transforms how the world develops software.

An overview of this role

As an Intermediate Backend Engineer on the Custom Models team, you'll help build and evolve Duo Self-Hosted, a key part of GitLab Duo that lets customers run AI-powered features in fully private environments and connect GitLab to their own AI models. You'll work across a mature codebase using Ruby on Rails, JavaScript, and Python to ship features that give our largest customers control, customization, and reliability as they adopt AI in sensitive and regulated contexts. You'll collaborate asynchronously with backend, frontend, product, and UX teammates across time zones, contributing to everything from new features to production issue resolution. Over your first year, you'll grow into owning projects from proposal through production. As the team returns to evaluating large language models (LLMs) and advancing AI capabilities, you'll also have the chance to deepen your impact at the intersection of AI, DevSecOps, and reliability for customers.

Some examples of our projects:

• Extending Duo Self-Hosted so customers can securely plug in their own LLMs and AI providers

• Improving performance and stability for large enterprise GitLab instances using AI capabilities

What you’ll do

• Contribute to Duo Self-Hosted features using Ruby on Rails, JavaScript, and Python, focusing on secure, reliable integrations between GitLab and customer AI models.

• Collaborate with backend, frontend, product, and UX teammates across time zones to design, scope, and deliver end-to-end solutions in an async-first environment.

• Develop, test, and maintain backend services and APIs (REST and/or GraphQL) with attention to scalability, maintainability, and backward compatibility.

• Write maintainable, well-tested code and participate in code reviews, giving and receiving feedback that improves code quality and team practices.

• Diagnose, troubleshoot, and resolve production issues, contributing to on-call or incident workflows and sharing learnings to prevent recurrence.

• Maintain and improve application quality and stability by addressing bugs, refining tests, and contributing to quality assurance efforts.

• Apply performance-minded thinking to identify and fix bottlenecks in the application and data layer, including SQL queries and background jobs.

• Take ownership of projects from proposal through deployment, iterating based on usage data and feedback from customers and internal stakeholders.

What you’ll bring

• Experience building and maintaining production applications with Ruby on Rails, including work with background jobs, APIs, and data models.

• Comfortable working across the stack in a mature codebase, contributing primarily to backend Ruby while also working with JavaScript and Python where needed.

• Proficiency in designing or extending REST and/or GraphQL APIs with attention to scalability, maintainability, and backward compatibility.

• Hands-on experience integrating large language models (LLMs) into applications, including prompt design and building features powered by generative AI.

• Strong SQL skills and familiarity with relational databases such as PostgreSQL, including writing efficient queries and understanding data modeling.

• Ability to identify and address performance bottlenecks at the application and, where relevant, infrastructure layers.

• Openness to learning, collaborating in an async-first, distributed team, and applying transferable skills from related technologies or domains.

About the team

We’re a distributed Custom Models team with GitLab team members across several European countries, Australia, and Canada. We collaborate closely with the AI Framework, MLOps, and Model Validation teams in an async-first way to deliver end-to-end AI capabilities. Together, we focus on creating a reliable, configurable experience for some of GitLab’s largest customers while exploring new opportunities in large language model evaluation and advancing GitLab’s AI-powered features.

How GitLab will support you

• Benefits to support your health, finances, and well-being

• Flexible Paid Time Off

• Team Member Resource Groups

• Equity Compensation & Employee Stock Purchase Plan

• Growth and Development Fund

• Parental leave

• Home office support

Please note that we welcome interest from candidates with varying levels of experience; many successful candidates do not meet every single requirement. Additionally, studies have shown that people from underrepresented groups are less likely to apply to a job unless they meet every single qualification. If you're excited about this role, please apply and allow our recruiters to assess your application.

Country Hiring Guidelines: GitLab hires new team members in countries around the world. All of our roles are remote, however some roles may carry specific location-based eligibility requirements. Our Talent Acquisition team can help answer any questions about location after starting the recruiting process.

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GitLab is proud to be an equal opportunity workplace and is an affirmative action employer. GitLab’s policies and practices relating to recruitment, employment, career development and advancement, promotion, and retirement are based solely on merit, regardless of race, color, religion, ancestry, sex (including pregnancy, lactation, sexual orientation, gender identity, or gender expression), national origin, age, citizenship, marital status, mental or physical disability, genetic information (including family medical history), discharge status from the military, protected veteran status (which includes disabled veterans, recently separated veterans, active duty wartime or campaign badge veterans, and Armed Forces service medal veterans), or any other basis protected by law. GitLab will not tolerate discrimination or harassment based on any of these characteristics. See also GitLab’s EEO Policy and EEO is the Law. If you have a disability or special need that requires accommodation, please let us know during the recruiting process.