Java Backend Engineer

About the project
Our client is a fintech company building a new digital banking and payments product from scratch. The platform will cover card and payment processing, integrations with banks and payment providers, and core financial services for end customers.
The product is at an early stage: architecture, team and roadmap are being shaped now, and the scope will be refined together with the team. You will join a mixed team of client and NerdySoft engineers. AI-assisted development is part of everyday engineering.
What you will do
Design, build and ship backend services for a new event-driven platform
Build reliable integrations with banking and payment providers – idempotent, traceable and easy to reconcile
Write clean, well-tested code: unit, integration and contract tests
Take part in technical design and architecture discussions together with the Tech Lead
Review code and share knowledge within the team
Work with AI coding assistants and AI agents in daily development: delegate tasks to agents, review the code they produce and keep it to the team's standards for review and testing
Follow secure coding practices and security requirements, including PCI DSS
Support your features in production: monitoring, troubleshooting, fixes
Communicate directly with the client's engineers and stakeholders
What you bring
3+ years of commercial backend development with Java (17+) and Spring Boot
Production experience with asynchronous, event-driven systems (Kafka, RabbitMQ, AWS SNS/SQS or similar)
Good knowledge of concurrency and transactions: ACID, isolation levels, locking
Relational databases (PostgreSQL preferred), JPA / Hibernate, SQL query optimisation
REST API design and integration with external services: retries, timeouts, idempotency, error handling
Testing as part of the definition of done: JUnit, Mockito, Testcontainers
Docker, CI/CD and hands-on AWS (or another major cloud)
Daily use of AI coding assistants (Claude Code, Cursor, GitHub Copilot or similar): you can show how they speed you up and how you check their output
English B2+ (Upper-Intermediate or higher): you will communicate directly with the client's team
Nice to have
FinTech background: banking, payments or lending products
Card issuing or processing: ISO 8583, authorisation, clearing and settlement, reversals
Visa or Mastercard integrations
PCI DSS in practice; secure public APIs (authentication, authorization)
Ledger systems and double-entry accounting
DDD, Clean or Hexagonal architecture
Kotlin, Kubernetes, Terraform
What we offer
Comfortable workplace and modern office facilities
Flexible working hours with no overtime and the ability to work remotely
50% compensation for certifications, conferences, training
50% compensation for English courses
18 working days of paid annual leave
Paid sick leave
Medical insurance and sports compensation