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Senior Backend Software Engineer - Consumer Banking
Scalapay
Source: Headcount Labs · original listing ↗
Job data: Headcount Labs, ODbL 1.0. Job descriptions belong to their employers.
Posted Oct 23
About this role
At Scalapay, we’re shaping a culture with high standards, independent and critical thought, innovation, ownership, and continuous learning. We operate in a fast-moving, tech-driven environment, and we’re looking for people who thrive in change, think boldly, and take initiative. If you’re ready to put your potential to the test in a hiring process designed to spotlight exceptional talent, this is your chance to stand out and grow with one of Europe’s most ambitious fintech teams. *#MakeItHappen #PlayAsATeam #StayCurious #FocusOnCustomer.* The Mission Scalapay is an AI-first international fintech. We're looking for a Backend Software Engineer with banking platform experience to join our Consumer Banking team. You'll design and deliver high-performance, secure and scalable APIs that power our customer experience. You'll work spec-first: you define what good looks like, and AI coding agents help you build it faster without lowering the bar on quality, security or compliance. Key Responsibilities: AI-First Engineering * Write clear specifications and technical designs that AI coding agents (e.g. Claude Code) implement from, then direct, review and test their output; * Take full ownership of AI-generated code, making sure it meets our standards for security, performance and PCI DSS compliance before it ships; * Use AI across the whole development lifecycle: test generation, code review, documentation, debugging and incident analysis; * Help shape the team's AI tooling, shared context, prompts and guardrails so that development becomes more automated over time. API Development & Integration * Design, build and maintain high-quality REST APIs using NestJS and TypeScript; * Meet performance targets of under 200ms response time through caching, query optimisation, payload compression, rate limiting, pagination and filtering; * Integrate with external services and banking partners, keeping the platform resilient to third-party failures. Architecture * Build scalable, maintainable microservices using dependency injection, modular design and clean code principles; * Develop event-driven systems and real-time features. Security & Compliance * Implement authentication and authorisation (JWT, OAuth2, MFA) and API security measures (TLS, API key management, request signing); * Apply secure coding practices, including input validation and protection against SQL injection and XSS; * Ensure PCI DSS compliance and encryption of sensitive data at rest and in transit. Data & Infrastructure * Design efficient MySQL/PostgreSQL schemas, manage migrations and optimise queries and indexing; * Deploy on AWS with Docker, EKS, and CI/CD pipelines, working with DevOps on infrastructure requirements; * Monitor system performance through logging, tracing and alerting. Required Qualifications * 5+ years of backend development experience, including banking platforms, system integrations and ledgers * 3+ years with NestJS and TypeScript, or comparable frameworks and languages * Proven AI spec-driven development: you've shipped production software by specifying, directing and validating the work of AI coding agents * Strong MySQL and/or PostgreSQL skills: schema design, query optimisation and indexing * Deep knowledge of REST API design, plus GraphQL experience (code-first and schema-first) * Track record of finding and fixing API performance bottlenecks, including caching (Redis, Memcached, HTTP caching) * Strong API security background: authentication, authorisation, encryption, security testing and vulnerability assessment * Experience with AWS (EC2, RDS, Lambda, API Gateway, CloudWatch) or a comparable cloud platform * Solid testing practice (Jest, unit and integration testing), Git workflows and agile delivery What We're Looking For * Banking platform experience. You’ve built or worked on banking systems, including system integrations and ledgers. * An AI-first builder. You can show us AI projects that demonstrate your spec-driven way of working, and you have good judgement about when to trust AI output and when to challenge it. * An owner. You think about performance, scalability and security by default, not as an afterthought. * A collaborator. You're comfortable with code reviews and enjoy sharing what you learn, including the AI workflows that work for you. * A continuous learner. You keep up with backend, security and AI-assisted engineering practices. Why Join Scalapay * Attractive packages based on skills and experience, the salary band we have for this position is of EUR 65'000 - 80'000 (Gross Annual Salary); * An international fintech with an AI-first approach, raising the bar daily on how we build software and solve complex problems * Work alongside industry tech leaders focused on exceptional user experiences * Personalised support to grow your career and take ownership of the products you deliver * Modern technology and the freedom to bring your own flair Recruitment Process: 1. A quick chat with one of our Talent Acquisition team members 2. The first interview with the Hiring Manager to dive deep into your experiences and better understand your motivation 3. A case study to test your hard skills 4. A final chat with Simone, our CEO Want to learn more? Don't hesitate to explore our [Careers website](https://www.scalapay.com/careers), our [LinkedIn](https://www.linkedin.com/company/scalapay/life/6dc706ba-9e50-4729-86a3-442e9a95f47d/) and [Glassdoor](https://www.glassdoor.fr/Overview/Working-at-Scalapay-EI_IE3872173.11,19.htm?countryRedirect=true) pages. *Pro tip:* send your CV in English 😉 *Super Pro tip:* we know that application processes can be scary and frustrating but… we look for talent, not people that tick all our boxes.