Senior Backend Developer

About This Opportunity

Our talent team is representing a confidential fintech organization operating a global payment infrastructure platform. They're seeking a Senior Backend Developer to join their core Checkout Team in Spain (remote). This is a full-time, individual contributor role requiring 5+ years of backend development experience.

You'll design and build high-performance transaction processing systems that handle millions of payment flows globally, working with a world-class engineering team in Kotlin and Go. This role sits at the intersection of payments engineering and AI-powered optimization, where the services you build enable intelligent routing and fraud prevention at scale.

Responsibilities

• Design, build, and evolve backend services and APIs in Kotlin and Go engineered for reliability, low latency, and massive scale
• Develop and maintain checkout payment flows including authorization, capture, refunds, reversals, and partial payments across multiple providers and regions
• Architect resilient event-driven microservices using Kafka and queuing systems to handle asynchronous payment processing with zero data loss
• Strengthen and expand the integration framework connecting to PSPs, acquirers, and payment gateways across countries and complex payment rails
• Apply OWASP principles and engineering best practices to ensure security, privacy, and PCI-DSS compliance
• Own the full lifecycle of features from technical design and implementation to monitoring and production operations
• Partner with Product, Compliance, and Business teams to turn real payment problems into elegant technical solutions
• Shape platform architecture through code reviews, technical decisions, and well-tested code

What We're Looking For

Required Qualifications:

• 5+ years of professional backend development experience
• Strong proficiency in a modern, statically-typed backend language (Kotlin and Go are the core stack)
• Deep expertise with payment processing concepts and financial systems
• Solid understanding of microservices architectures, including building and operating them in production
• Experience with relational databases (PostgreSQL or similar) and data modeling for financial systems
• Containerization and cloud infrastructure experience (Docker, Kubernetes, AWS or GCP)
• Strong command of unit, integration, and contract testing practices
• Fluent English, written and verbal

Preferred Qualifications:

• Hands-on experience with Kotlin and/or Go (Golang), Spring Boot, or Spring WebFlux
• Background in fintech, neobank, or payment orchestration environments
• Experience with Kafka or other event streaming platforms
• Familiarity with PCI-DSS, PSD2, or 3DS authentication frameworks
• Observability tooling such as Datadog, OpenTelemetry, or distributed tracing
• Knowledge of network tokenization, smart routing, or payment optimization strategies
• Prior work at high-growth startups operating across multiple markets
• Spanish proficiency is a plus

Tech Stack: Kotlin, Go, Spring Boot, Apache Kafka, PostgreSQL, Redis, AWS, Kubernetes, Docker, Terraform, Datadog, OpenTelemetry, GitHub Actions

How We Work with You

When you apply through Get A Job.ai, our recruiting team will review your profile and conduct an initial screening to ensure alignment with the role requirements. If there's a strong match, we'll submit your candidacy to our client for consideration and guide you through their interview process. Please apply only through Get A Job.ai—do not contact the client directly, as we are managing this search exclusively.

Pay

Compensation details will be discussed during the screening process and are competitive for senior backend engineering roles in the European fintech market.

Equal Opportunity: Get A Job.ai is committed to inclusive recruiting practices. We welcome applications from candidates of all backgrounds and work to ensure equitable access to opportunities.