Role overview

Scalapay is an AI-first international fintech looking for a Senior Backend Software Engineer to join the Consumer Banking team in Milan. You will design and deliver high-performance, secure and scalable APIs that power customer experiences, working in a spec-first approach where you define requirements and AI coding agents help accelerate development while you maintain full ownership of code quality, security and compliance.

Key responsibilities

Write clear specifications and technical designs that AI coding agents implement, then review, test and validate the output to ensure it meets security, performance and PCI DSS compliance standards.
Design, build and maintain high-quality REST APIs using NestJS and TypeScript that meet performance targets of under 200ms response time through caching, query optimisation, payload compression and filtering.
Build scalable, maintainable microservices using dependency injection, modular design and clean code principles, and develop event-driven systems and real-time features.
Implement authentication and authorisation mechanisms including JWT, OAuth2 and MFA, plus API security measures such as TLS, API key management and request signing.
Design efficient MySQL and PostgreSQL schemas, manage migrations and optimise queries and indexing to support banking operations.
Deploy systems on AWS using Docker and EKS with CI/CD pipelines, and monitor performance through logging, tracing and alerting.
Help shape the team’s AI tooling, shared context and guardrails to make development more automated over time.

Requirements

At least 5 years of backend development experience including work on banking platforms, system integrations and ledgers.
At least 3 years working with NestJS and TypeScript, or comparable frameworks and languages.
Proven experience shipping production software using AI spec-driven development, where you specify requirements, direct AI coding agents and validate their output.
Strong skills with MySQL and PostgreSQL including schema design, query optimisation and indexing.
Deep knowledge of REST API design and experience with GraphQL in both code-first and schema-first approaches.
Demonstrated ability to identify and fix API performance bottlenecks using caching technologies like Redis and Memcached.
Strong background in API security covering authentication, authorisation, encryption, security testing and vulnerability assessment.
Experience with AWS services such as EC2, RDS, Lambda, API Gateway and CloudWatch, or equivalent cloud platform experience.
Solid testing practice with Jest, unit and integration testing, proficiency with Git workflows and familiarity with agile delivery.

What makes this role worth considering

Scalapay operates as an AI-first fintech in a fast-moving, tech-driven environment where you’ll work alongside industry leaders focused on exceptional user experiences. The role offers an attractive salary package ranging from EUR 65,000 to EUR 80,000 gross annual salary, personalised career development support and the freedom to bring your own approach to modern technology.