Senior Backend Engineer - Checkout

Job description

Salla's engineering team focused on Fintech, Checkout and Promotions needs a Senior Backend Engineer to design, build and scale highly available backend systems behind mission-critical payment experiences, checkout flows, promotions, loyalty and pricing.

The role suits engineers who enjoy distributed systems problems, high-performance services and resilient, observable software, and who work closely with Product, Design, Data and Engineering teams on systems that handle millions of transactions.

Responsibilities

• Design, build, and operate scalable backend services supporting Fintech, Checkout, Promotions, Loyalty, and Payment systems.
• Develop clean, maintainable, and high-performance production code with readability and long-term ownership in mind.
• Design and evolve RESTful APIs and integrations with internal platforms, payment gateways, and third-party services.
• Build reliable distributed systems capable of handling high traffic, failures, and asynchronous workloads.
• Drive architectural decisions with scalability, resilience, maintainability, and operational excellence in mind.
• Optimize application performance across services, databases, caching layers, queues, and background workers.
• Participate in architecture discussions, technical design reviews, RFCs, and engineering planning.
• Ensure services are production-ready through monitoring, logging, alerting, testing, and observability best practices.
• Write comprehensive unit and integration tests while maintaining high engineering standards through code reviews.
• Leverage AI-assisted engineering tools responsibly to accelerate development, debugging, testing, documentation, and code quality.
• Mentor junior and mid-level engineers through technical leadership, design discussions, and engineering best practices.
• Contribute throughout the full software development lifecycle, from design through deployment and production support.
• Continuously improve system reliability, developer experience, and engineering standards across the team.

Requirements

• 6+ years of professional software engineering experience building production backend systems.
• Strong experience building scalable backend services in at least one modern language such as PHP, Go, Java, or C#.
• Experience with PHP and Laravel is preferred but not required.
• Strong understanding of distributed systems fundamentals, including consistency, availability, concurrency, fault tolerance, idempotency, asynchronous processing, messaging, and caching.
• Experience designing and operating high-scale, highly available backend systems.
• Proven ability to write clean, maintainable, efficient, and high-performance production code.
• Strong understanding of software engineering principles, including SOLID, design patterns, clean architecture, and domain-driven design concepts.
• Experience designing RESTful APIs and integrating with third-party platforms and payment providers.
• Strong SQL knowledge with experience designing and optimizing MySQL or PostgreSQL databases.
• Experience with caching technologies, queues, background workers, and performance optimization.
• Experience writing automated tests, participating in code reviews, and working within modern CI/CD pipelines.
• Comfortable using AI-assisted development tools to improve productivity, software design, implementation, testing, debugging, documentation, and code reviews.
• Experience building Fintech, Payments, Checkout, Loyalty, Pricing, Promotions, or other high-volume transactional systems.
• Experience with event-driven architectures and distributed messaging systems.
• Experience with Docker, Kubernetes, cloud platforms (AWS, GCP, or Azure), and Infrastructure as Code.
• Experience with observability platforms, distributed tracing, metrics, and production monitoring.
• Experience working within microservices or service-oriented architectures.
• Bachelor's or Master's degree in Computer Science, Software Engineering, or a related field is a plus.

Skills

• CI/CD
• Distributed Systems
• Go
• Java
• Laravel
• MySQL
• PHP
• PostgreSQL
• REST APIs