Senior Ruby Developer (Ruby & Go)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Ruby Developer (Ruby & Go) based in United Kingdom.

This is a senior backend engineering opportunity focused on building and scaling secure, reliable payment infrastructure for a global fintech environment. You will take ownership of the backend powering payment portals and integrations with payment service providers. The role combines Ruby on Rails expertise with Go development for high-throughput and latency-sensitive services. You will design end-to-end deposit and withdrawal flows while ensuring robust transaction processing, reconciliation, and failure handling. Security and reliability are central, with a strong focus on financial data protection and compliance. You will also contribute to technical direction, mentor engineers, and help evolve a high-performing international engineering environment.

• Design, build, maintain, and own backend services using Ruby on Rails and Go, with a focus on scalability, reliability, and maintainability.
• Lead the integration of new payment service providers and payment methods, including cards, bank transfers, cryptocurrency, and local payment solutions.
• Build and maintain end-to-end deposit and withdrawal workflows, ensuring secure and consistent movement of funds across the platform.
• Design, implement, and consume PSP APIs, webhooks, callbacks, and other integration mechanisms.
• Develop transaction routing, status tracking, reconciliation, and payment lifecycle logic.
• Implement robust handling for payment states, retries, idempotency, failures, and edge cases to ensure resilient transaction processing.
• Maintain strong security controls for payment information and support compliance requirements, including PCI DSS.
• Monitor existing payment provider integrations, troubleshoot issues, and proactively improve reliability and performance.
• Develop reporting, logging, and observability capabilities that support payment operations and technical troubleshooting.
• Support the integration of anti-fraud, AML, and KYC controls into payment workflows.
• Provide technical leadership through architecture discussions, code reviews, technical decision-making, and mentorship of other engineers.

Requirements

• 5+ years of backend engineering experience, particularly in API-driven and integration-heavy environments.
• Strong professional experience with Ruby and Ruby on Rails, with production-level experience in Go strongly preferred.
• Proven experience integrating payment service providers, payment gateways, or comparable financial APIs.
• Strong understanding of payment flows, webhooks, callbacks, transaction lifecycles, and payment states.
• Knowledge of PCI DSS and secure handling of sensitive financial and payment data.
• Hands-on experience with reconciliation, idempotency, retries, error handling, and other patterns required for reliable financial transactions.
• Experience designing, developing, and scaling distributed backend systems.
• Previous experience in fintech, payments, Forex, CFD brokerage, or related financial technology environments is preferred.
• Strong understanding of backend reliability, security, observability, and performance considerations.
• Excellent attention to detail, with a strong focus on building secure and dependable financial systems.
• Ability to communicate technical decisions clearly and contribute effectively to an international, collaborative engineering team.

Benefits

• Fully remote position.
• Monday–Friday schedule, from 9:00 to 18:00.
• Visa sponsorship.
• Medical insurance starting from the first week.
• Career growth opportunities within a fast-scaling fintech environment.
• Opportunities to participate in international events, meetups, and business trips to global offices.
• Exposure to international payment technologies, financial products, and high-scale backend systems.