Expert de Backend - Java
Equação IT is a company focused on boosting technology and solid solutions through our expert consultants leading a high perspective and adding value to our customers with the purpose of providing optimization and business growth to our partners.
Role description:
We are looking for a Senior Backend Java Developer with extensive experience in Java and Spring Boot, capable of leading a small development team while designing and implementing modern, scalable, API-first backend solutions. The successful candidate will play a key role in transforming functional and architectural specifications into high-quality technical solutions, following best practices in software engineering, cloud-native development, and continuous delivery.
Functions:
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.
Technologies/Skills:
Java / Spring Boot - essential
At least 5 years of previous experience with Java and Spring Boot backend projects.
Strong knowledge of modern Java practices, including immutability, records where appropriate, Optional
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.
• Duration: Long Term Contract.
• Availability to work in a hybrid model (2 days per week in the Lisbon office).
