Make this the place where you grow.
As a global leader in business and technology innovation, we work with top organizations worldwide to deliver solutions that create meaningful impact.
With 190,000+ professionals across 70+ countries, we blend deep expertise with a culture that values learning, curiosity, and collaboration.
We lead transformation and deliver secure, innovative, industry-specific solutions that move businesses forward. Our people drive everything we achieve, they think bold to deliver the outcome while ensuring every voice is heard.
NTT Data Greece is looking for a motivated and experienced Lead Senior Java Backend Engineer / Squad Lead in Athens to support our client on a European institution project.
Your role:
- Develop backend application features from detailed functional and architecture specifications.
- Design and implement API-first backend services and REST APIs aligned with agreed OpenAPI contracts.
- Translate functional and high-level architecture specifications into detailed technical designs and implementation plans.
- Lead and mentor a squad of 2-3 less experienced engineers, providing technical guidance, code review, and day-to-day engineering support.
- Contribute to backend architecture decisions, ensuring separation of concerns, clear bounded contexts, maintainability, scalability, and operational simplicity.
- Produce quality code including unit testing, integration testing, contract validation, and architectural governance checks.
- Support CI/CD-driven delivery, trunk-based development, short-lived feature branches, and reliable release practices.
- Collaborate with architects, business analysts, UX designers, QA, DevOps and frontend teams in an international delivery environment.
Your profile:
Java / Spring Boot - essential
- Over 5 years of previous experience with Java and Spring Boot backend projects.
- Strong knowledge of modern Java practices, including immutability, records where appropriate, Optional, Streams API, constructor-based dependency injection and clean service/repository layering.
- Experience with Spring WebFlux or reactive programming for I/O-bound, asynchronous, high-concurrency or event-driven processing.
- Experience building maintainable backend modules with clear separation between controllers, services, repositories, DTOs and domain logic.
- Experience with MapStruct or equivalent mapper patterns to avoid exposing persistence entities through APIs.
- Strong Spring Security knowledge, including OAuth2 / OpenID Connect, JWT validation/enrichment, authorization rules and method-level security.
API and integration
- Experience developing RESTful APIs and working with API-first delivery using OpenAPI specifications.
- Knowledge of API design best practices: resource-oriented URLs, versioned API paths, structured error payloads, pagination, filtering, idempotency and secure-by-design endpoints.
- Experience reading, writing and manipulating JSON, XML, XSD and related data-exchange formats.
- Experience with asynchronous/event-driven API design, AsyncAPI specifications, correlation/traceId propagation and message contract governance.
- Experience with third-party application integration and resilient external-service communication.
Databases and data modelling
- Hands-on experience with MongoDB as a document datastore, including data modelling, indexing, query optimisation and schema evolution.
- Knowledge of MongoDB migrations, versioned scripts, migration metadata, expand/contract patterns and zero-downtime compatibility during rolling upgrades.
- Experience with transactional consistency patterns such as transactional outbox, idempotent consumers, retry state, lease/claim ownership and operational checkpoints.
- Knowledge of SQL and experience with relational data modelling is valuable.
Testing and quality engineering
- Strong experience with JUnit 5, Mockito / Spring MockBean and fast unit testing of business logic.
- Experience with integration testing using Testcontainers and controlled external-system test environments.
- Familiarity with contract and API quality tools such as OpenAPI Generator, Spectral, OASDiff, Schemathesis, Microcks, RESTler-fuzzer or OWASP ZAP is valuable.
- Experience enforcing architecture rules with ArchUnit or equivalent governance techniques.
- Ability to maintain high code quality through peer review, automated checks, observability and traceable error handling.
DevOps / cloud-native delivery
- Experience with Docker and Kubernetes-based deployment models.
- Knowledge of Helm-based deployments, Kubernetes Jobs for migrations, CI/CD pipelines, automated build validation and security scanning.
- Comfortable with Linux command line, Git, Maven and operational troubleshooting through logs.
- Experience supporting high-availability systems, zero-downtime deployments, rollback/roll-forward planning and production-safe migration strategies.
Leadership and delivery
- Proven ability to lead a small engineering squad of 2-3 less senior members while remaining hands-on in design and development.
- Ability to simplify complex technical specifications into actionable tasks and provide clear technical direction to the team.
- Comfortable working in Agile / Scrum delivery frameworks, participating in refinement, estimation, sprint planning and technical risk management.
- English level B2 or higher; able to attend and participate fully in daily technical meetings in English. Experience in international projects is highly valuable.
This role describes your starting point at NTT DATA. We believe in long‑term relationships and in supporting your growth. As your skills and ambitions evolve, we will work with you to identify future opportunities, projects, and career paths across our organization.
🌟 Why NTT DATA?
🤝 A collaborative and supportive culture
We foster an environment where curiosity, innovation, engagement, and teamwork are celebrated. Our people‑first philosophy is one of the core reasons we continue to be recognized globally.
🚀 Career development & continuous learning
Access a structured training path, ongoing learning resources, annual performance reviews, and a dedicated mentorship program — all designed to help you grow professionally and take on new challenges.
💻 Work–life balance supported by our BeFlex policy
As a company, we embrace a BeFlex approach that empowers our people with a level of flexibility in how they manage their workday.
✨ Global Top Employer
We are proudly certified as a Global Top Employer acknowledging our commitment to being a place where people can grow and thrive.
🌿 Health & well‑being first
Your mental well‑being matters. Employees have access to certified psychologists and online mental health workshops.
🌈 Diversity, Equity & Inclusion
We are committed to creating a workplace where everyone can thrive, regardless of gender, nationality, sexual orientation, disability, age, or background. Inclusion is part of who we are and how we work.
#WeAreAllUnique #YouMakeUsUnique
Upon receiving an interview, you may request accommodation for any accessibility needs.
Benefits at NTT DATA Greece
Health insurance for the employee and one dependent family member (100% paid by NTT DATA)
Meal vouchers of 120€ per month (x12)
Corporate mobile phone: subscription & device
Teleworking equipment allowance
Ιnternal Trainings Platform Account
Access to Open Up mental health service
26 days of paid annual leave consisting of your legal holidays and compensation days. Plus 2 fixed vacation days: Good Friday & Whit Monday
GR
