Freelance Staff Backend Engineer (Ruby)

Requirements

• We’re looking for a senior freelance engineer who can quickly create impact in a scale-up environment and operate with a high degree of autonomy
• Mission-Driven & Customer-Focused: You are passionate about solving real-world problems and are driven to connect technical solutions with customer value and business impact
• Deep Technical Expertise: You have 8 years experience with technologies in high-throughput environments, with at least 2-3 years in Ruby on Rails
• Proven Architect: You have a proven track record of architecting, building, and operating complex, large-scale systems, particularly those with asynchronous workflows and demanding workloads
• Observability Expert: You have hands‑on experience implementing and leveraging observability tools (e.g., Datadog, Prometheus, Grafana) to ensure system health and performance
• Dev

  Ops & Infrastructure Acumen: You possess a strong Dev

  Ops mindset and practical experience in scaling and tuning applications on container orchestration platforms like Kubernetes
• Performance Master: You have deep expertise in performance analysis and optimization, capable of debugging bottlenecks in application code, databases (e.g., PostgreSQL), and infrastructure
• Collaborative Leader: You have excellent communication and collaboration skills, with a history of working effectively in agile teams, partnering with product management, and influencing technical direction without direct authority
• Continuous Learner: You maintain a strong technical watch on the evolving ecosystem, knowing how to identify and apply best practices from different communities to solve problems creatively
• (Desirable) Direct experience in designing, building, and deploying applications powered by Large Language Models (LLMs)
• (Desirable) Experience working in a high-growth B2B SaaS environment
• (Desirable) A data-driven approach to decision‑making, from product analytics to application monitoring

What the job involves

• Contract type: Freelance / Contractor
• As a Freelance 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 architect for scale and resilience, while helping us rethink our evaluation process through the integration of LLM-based insights
• You will be brought in to lead some of our most complex and ambitious technical initiatives, shaping advanced solutions from ambiguous requirements through to execution. Working within a dedicated squad, you will collaborate closely with our Engineering Manager, Product Manager, and engineers to turn strategic vision into technical reality and further strengthen Trustpair’s position as a market leader
• Architect and Own: 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 Technical Strategy: Lead complex, cross-functional technical projects from conception to completion, ensuring alignment with product strategy and client needs
• Shape the Future: Partner with Product and Engineering leadership to build and refine the technical roadmap. You will identify key technical challenges and propose innovative solutions that drive our business forward
• Drive Innovation: Champion a culture of innovation and continuous improvement. You will be 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
• Mentor and Elevate: 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. Help the engineering manager drive the cultural shift to strengthen the customer focus
• Ensure Operational Excellence: Promote and implement best practices for observability, scalability, and performance, ensuring our core systems are reliable and efficient