Job description
TL;DR
Senior Backend Developer (Fintech): development and evolution of a high-load acquiring platform with a microservice architecture, focusing on fault tolerance and security. Emphasis on designing payment systems, working with asynchronous data streams via Kafka/RabbitMQ, and optimizing the performance of 24/7 services.
Senior Backend Developer (Fintech)
SMARTCORE AG | Barcelona, Catalonia, Spain (Remote)
About the company:
SmartCore is a fintech holding company building the infrastructure for the next generation of payments. Our solutions cover the entire financial operations cycle: from core banking and processing to cards, wallets, and anti-fraud systems.
About the project:
You will join a key team responsible for the development and evolution of our core acquiring platform. This is a complex, high-load system with a microservice architecture, operating 24/7. We are responsible for the entire payment lifecycle – from initiation to clearing, ensuring minimal latency, high fault tolerance, and compliance with strict security standards (PCI DSS).
Your responsibilities will include:
- Designing and developing new microservices and business logic.
- Optimizing the performance of existing system components, working with high-load code sections.
- Making key architectural decisions aimed at improving the fault tolerance, scalability, and security of the platform.
- Integration with third-party payment systems, banks, and processing centers.
- Working with asynchronous data streams using Kafka and RabbitMQ.
- Conducting code reviews, mentoring less experienced colleagues, and implementing best development practices.
- Active participation in R&D, researching and implementing new technologies in the project stack.
- Covering code with unit and integration tests, maintaining high code quality.
Our ideal candidate:
- Has commercial backend development experience of 5+ years in one of the following languages: Java, Kotlin, Python, Node.js, Golang, C#.
- Has practical experience with any SQL database (PostgreSQL, Oracle, MySQL, etc.): experience in query optimization, understanding of transaction isolation levels.
- Practical experience in building systems based on Kafka: understanding of broker principles, producer/consumer patterns, message delivery guarantees.
- Experience in designing services and system design of distributed systems.
- Understanding of network protocol principles (TCP/IP, HTTP/2, gRPC).
- Experience with containerization and orchestration tools (Docker, Kubernetes).
- Habit of writing clean, maintainable, and well-testable code.
- Possesses a high degree of autonomy, is proactive, takes responsibility for the final result and product quality.
- Fluent in Russian (B2 or higher) – mandatory for daily team communication.
Will be a plus:
- Experience in fintech or payment processing, knowledge of PCI DSS standard.
- Well-oriented in modern AI technologies, including AI agents, and can apply various LLMs in their work.
- Experience with NoSQL databases (MongoDB, Redis).
- Familiarity with RabbitMQ.
- Experience using monitoring and tracing tools (Prometheus, Grafana, Jaeger).
- Experience with load testing (JMeter, Gatling).
We offer:
- Competitive salary, discussed individually with each candidate.
- Modern technology stack and no bureaucracy.
- Budget for training, attending industry conferences, and purchasing literature.
- Corporate access to all advanced LLM models in Max configuration.
- Work in a team of experts passionate about their work, where your opinion will always be heard.
To apply or clarify details, you can contact us directly via chat or email: stanislav.pavlov[@]smartcore.pro
