Senior Java Developer
Summary
Build and maintain high-traffic microservices for a travel platform using Java, Spring Boot, Quarkus, gRPC, and REST in a hybrid Istanbul role.
Employment Type: Full-time
Experience: 7+ Years
About the Role
We are looking for an experienced Senior Java Developer to join the development team of a high-traffic, enterprise-level travel and tourism platform actively used in production.
The platform supports end-to-end customer journeys across flight, hotel, car rental, transfer, and payment services and operates within a complex technology ecosystem consisting of multiple microservices, a large-scale legacy Java EE core, modern web and mobile channels, and various third-party integrations.
The technology environment includes:
- Core domain services built primarily with Java and Spring Boot
- Rule engine and next-generation services utilizing Java and Quarkus, including reactive and native approaches
- Service-to-service communication primarily through gRPC and REST
- Modern web and mobile applications integrated with enterprise and legacy systems
Key Responsibilities
- Design, develop, and maintain scalable enterprise applications using Java, Spring Boot, and Quarkus
- Contribute to high-traffic, production-critical microservice architectures
- Participate in the modernization and integration of legacy Java EE applications
- Develop and maintain REST and gRPC-based services
- Perform technical analysis of business requirements and prepare technical documentation
- Produce testable and measurable software outputs in line with defined development processes, best practices, and coding standards
- Monitor application performance, logs, and metrics
- Collaborate with frontend, mobile, DevOps, architecture, and other technical teams
- Participate in code reviews and contribute to software quality and engineering standards
- Work within Agile software development methodologies
Must-Have Qualifications
- Bachelor’s degree, preferably in Computer Engineering, Software Engineering, Computer Science, or a related field
- 8+ years of professional software development experience
- Strong hands‑on experience with Java and Spring Boot
- Experience with Quarkus / Java, including reactive and/or native application development
- Strong understanding of microservices architecture
- Hands‑on experience with gRPC and REST APIs
- Strong experience with SQL and PL/SQL
- Familiarity with modernization of legacy enterprise Java technologies such as EJB, JSF, and WildFly
- Hands‑on experience with Docker, Kubernetes, and CI/CD processes
- Strong understanding of software development best practices and coding standards
- Experience working within Agile development environments
Good to Have
- Experience designing authentication and authorization flows using Keycloak, OAuth 2.0, JWT, SSO and/or SAML
- Familiarity with Next.js, React, and TypeScript sufficient to collaborate effectively with frontend teams
- Experience with SAP/ERP integrations, particularly SOAP/WSDL
- Knowledge of Object-Oriented Programming (OOP) and/or functional programming principles
- Experience with source-code branching strategies, particularly GitFlow
- Experience with application observability, performance monitoring, logging, and metrics
What We’re Looking For
We are looking for a technically strong and experienced developer who is comfortable working within a large-scale, high-traffic enterprise ecosystem combining modern microservices with legacy systems.
The ideal candidate is passionate about software engineering, follows emerging technologies, values clean and maintainable code, and is comfortable taking ownership of technically complex applications.
This is a hybrid position based in Istanbul, requiring 2 days per week on-site in Ümraniye.