Staff Backend Engineer (Ruby) M/F/Mx

About the role

As a Staff Software Engineer on our Core Evaluation team, you will be a technical authority driving the evolution of our most critical asset: the fraud detection engine. This is a pivotal role where you'll not only architect for scale and resilience , but also spearhead the integration of LLM‑based insights to rethink our evaluation process.

You will be entrusted with our most complex and ambitious projects , shaping advanced solutions from ambiguous requirements. Working within a dedicated squad, you will collaborate closely with your Engineering Manager, Product Manager, and fellow engineers to turn a strategic vision into a technical reality that further strengthens Trustpair's position as a market leader.

Location: either Paris (hybrid), or full remote in France.

What you’ll do

• Design, architect, and own the technical vision for large‑scale, distributed systems at the heart of our platform, with a focus on our complex evaluation workflows.
• Lead complex, cross‑functional technical projects from conception to completion, ensuring alignment with product strategy and client needs.
• Partner with Product and Engineering leadership to build and refine the technical roadmap, identifying key technical challenges and proposing innovative solutions that drive our business forward.
• Champion a culture of innovation and continuous improvement, directly involved in transforming the Trustpair engine by exploring and implementing new technologies, with a strong focus on applying LLM‑based solutions to solve complex business problems.
• Act as a technical mentor and force multiplier for engineers within your squad and across the organization, promoting best practices in software architecture, design, and strategic thinking.
• Promote and implement best practices for observability, scalability, and performance, ensuring our core systems are reliable and efficient.

What’s in it for you

• High‑Impact in a High‑Growth Environment: Join a company with 50%+ business growth where tech is one of the core accelerators. Build solutions for a platform with rapidly increasing usage, directly influencing our success.
• Shape Our Future (Scale‑up Phase): Have your voice in making critical architectural, product, and organizational decisions that will define our future.
• Modern Stack & AI‑Powered Engineering: Work with a clean Ruby on Rails stack, state‑of‑the‑art DevOps, and managed tech debt while adopting AI in our product and for personal efficiency.
• Culture of Full‑Fledged Engineering Ownership: Drive initiatives from technical design to final impact, with full accountability and influence.
• Accelerated Career Growth: Rapid expansion creates continuous opportunities for advancement, skill development, and new leadership responsibilities.
• Collaborative & International Team: Thrive in a diverse, cross‑functional, and international environment.

Must Haves

• Mission‑Driven & Customer‑Focused: Passionate about solving real‑world problems and connecting technical solutions with customer value and business impact.
• Deep Technical Expertise: At least eight years of experience with high‑throughput environments and 2–3 years in Ruby on Rails.
• Proven Architect: A track record of building and operating complex, large‑scale systems in asynchronous workflows with demanding workloads.
• Observability Expert: Hands‑on experience with tools such as Datadog, Prometheus, and Grafana to ensure system health and performance.
• DevOps & Infrastructure Acumen: Strong DevOps mindset and experience scaling applications on container orchestration platforms like Kubernetes.
• Performance Master: Deep expertise in performance analysis and optimization, debugging bottlenecks in code, databases (e.g., PostgreSQL), and infrastructure.
• Collaborative Leader: Excellent communication and collaboration skills, effectively working in agile teams, partnering with product management, and influencing technical direction without direct authority.
• Continuous Learner: Maintains a strong technical watch on evolving ecosystems, applying best practices to solve problems creatively.

Bonus Points

• Direct experience designing, building, and deploying applications powered by Large Language Models (LLMs).
• Experience in a high‑growth B2B SaaS environment.
• A data‑driven approach to decision‑making, from product analytics to application monitoring.

Equal Opportunity Statement

Trustpair's policy is to provide equal employment opportunity in all of our employment practices without regard to race, color, religion, sex, national origin, ancestry, marital status, protected veteran status, age, individuals with disabilities, sexual orientation or gender identity or expression or any other legally protected category.

Applicants for all positions in Trustpair must be legally authorized to work in the country which they are applying for or be a citizen from Schengen/EU zone. Verification of employment eligibility will be required as a condition of hire.