Senior Backend Software Engineer – PHP & Java | High-Performance Systems

🌍 100% Remote | Must be based in Portugal 💻 Tech Stack: PHP, Java, Go, PostgreSQL, AWS, GitHub, Grafana Are you a highly experienced Senior Backend Software Engineer who thrives on solving complex engineering challenges, designing scalable architectures, and building mission-critical systems? We're looking for an exceptional Senior Backend Engineer to join an international engineering team responsible for developing and evolving a core financial processing platform handling high transaction volumes. This is an opportunity for a technically strong professional with deep expertise in PHP, Java, backend architecture, distributed systems, and database performance, who is passionate about engineering excellence, scalability, and reliability. You'll play a key role in modernizing existing services, optimizing critical systems, and contributing to the evolution of the platform toward Go-based architectures. 🚀 What You'll Be Doing: Backend Engineering & System Architecture: - Design, develop, and maintain highly scalable backend services and B2B APIs using PHP and Java. - Build robust, high-performance systems capable of processing large transaction volumes. - Take end-to-end ownership of complex engineering challenges, from technical design to production. - Design scalable APIs, data models, and distributed architectures with a strong focus on reliability, security, and maintainability. - Contribute to the modernization and migration of existing PHP and Java services toward Go. Performance, Scalability & Reliability: - Identify and resolve performance bottlenecks across applications, databases, and distributed systems. - Optimize PostgreSQL databases, including complex SQL queries, indexing strategies, and database performance. - Design and implement asynchronous processing, concurrent workloads, and resilient architectures. - Implement robust error-handling, retry, recovery, and dead-letter mechanisms. - Ensure high availability, fault tolerance, and operational stability of business-critical services. Engineering Excellence & DevOps: - Develop clean, maintainable, well-tested, and production-ready code. - Implement observability solutions using structured logging, metrics, distributed tracing, and monitoring tools. - Apply security best practices throughout the software development lifecycle. - Contribute to automated testing, CI/CD pipelines, containerization, and cloud deployments. - Participate in code reviews, architecture discussions, and technical decision-making. - Collaborate with experienced engineers to continuously improve engineering standards and practices. 🎯 What We're Looking For – Must Have: We're looking for a genuinely senior engineer with outstanding technical depth, strong problem-solving abilities, and proven experience building complex backend systems. - Strong professional experience with both PHP and Java, including hands-on development of production-grade backend applications. - Extensive experience designing and developing scalable, high-performance backend services and REST APIs. - Deep understanding of relational databases, SQL optimization, indexing, and query performance, ideally with PostgreSQL. - Proven experience working with high-throughput, transaction-intensive, or business-critical systems. - Strong knowledge of distributed systems, asynchronous processing, concurrency, and fault-tolerant architectures. - Solid understanding of software architecture, system design, design patterns, and API security. - Demonstrated ability to troubleshoot complex production issues and resolve performance bottlenecks. - Strong commitment to code quality, automated testing, maintainability, and engineering best practices. - Ability to work independently, take technical ownership, and make sound architectural decisions. - Excellent analytical, troubleshooting, and problem-solving skills. - Strong communication skills and the ability to collaborate effectively in an international engineering environment. - Must currently reside in Portugal. ⭐ Nice to Have: - Hands-on experience with Go (Golang), particularly in backend services or system modernization. - Experience migrating legacy applications or services to modern architectures. - Experience with AWS and cloud-native environments. - Familiarity with Grafana, Loki, Alloy, or similar observability and monitoring solutions. - Experience with GitHub, CI/CD pipelines, Docker, and containerized environments. - Previous experience in FinTech, banking, payments, or other high-volume transactional platforms. - Experience working in Agile development environments. 💡 What Makes This Opportunity Special? - 100% remote opportunity, exclusively for professionals based in Portugal. - Work on a mission-critical financial platform where performance, scalability, and reliability truly matter. - Tackle challenging engineering problems involving high transaction volumes and distributed systems. - Contribute to a strategic technology modernization journey involving PHP, Java, and Go. - Collaborate with an experienced international engineering team. - Have a meaningful impact on technical architecture, engineering decisions, and platform evolution. 🚀 Ready for Your Next Challenge? If you're a highly skilled Senior Backend Engineer with strong expertise in PHP and Java, a passion for complex technical challenges, and experience building scalable, reliable systems, we'd love to hear from you!