Senior Software Engineer – High‑Scale Payments & Billing Backend

About the role

This senior engineering position is based in Portugal and focuses on building and evolving high‑scale backend systems that power global e‑commerce for software and digital products. The role centers on mission‑critical payment, subscription, billing, and reporting platforms that handle millions of transactions across multiple currencies and regions.

Key responsibilities

• Lead the design and development of backend features for high‑availability payment, subscription, settlement, refund, and reporting systems.
• Build and maintain integrations with external payment processors, card networks, and alternative payment methods.
• Design scalable, secure, and maintainable service‑oriented architectures with a strong focus on reliability and performance.
• Debug and resolve complex production issues across money‑movement flows, ensuring minimal downtime.
• Break down large technical initiatives into incremental, deliverable tasks for agile cycles.
• Participate in architecture discussions, design reviews, and code reviews to uphold high engineering standards.
• Collaborate with product, risk, finance, and compliance teams to implement regulatory and business requirements.
• Improve CI/CD pipelines, testing strategies, and deployment processes.
• Mentor junior engineers and promote best practices in coding, testing, and system design.
• Identify performance bottlenecks, operational risks, and opportunities for system optimization.

Required profile

• 10+ years of professional software engineering experience delivering production‑grade SaaS or backend systems.
• Strong expertise in Java and building distributed, service‑oriented architectures.
• Solid experience with SQL (PostgreSQL) and NoSQL databases in production environments.
• Proven track record designing and implementing RESTful APIs and scalable backend services.
• Hands‑on experience with AWS services such as EC2, S3, RDS, DynamoDB (Lambda a plus).
• Deep understanding of system reliability, performance, and security.

Required skills

• Java
• PostgreSQL
• NoSQL databases
• RESTful API design
• AWS EC2
• AWS S3
• AWS RDS
• AWS DynamoDB
• AWS Lambda (optional)