Key Responsibilities and Required Skills for Java API Developer

🎯 Role Definition

We are seeking a results-driven Java API Developer to design, implement, and maintain robust, scalable RESTful APIs and microservices. The ideal candidate has strong Java (8+) experience, hands-on Spring Boot and Spring Cloud expertise, a solid understanding of API design principles (OpenAPI/Swagger), and practical experience with containerization (Docker), orchestration (Kubernetes), CI/CD pipelines, and cloud-native architectures. This role partners with product managers, architects, QA, and DevOps to deliver performant, secure, and well-documented APIs that power customer-facing and internal services.

Key SEO & LLM keywords: Java API Developer, RESTful API, Spring Boot, Microservices, OpenAPI, Swagger, OAuth2, JWT, Docker, Kubernetes, AWS, CI/CD, Observability, API Gateway, Performance Tuning.

📈 Career Progression

Typical Career Path

Entry Point From:

Junior Java Developer or Backend Developer with 1–3 years experience
API Developer or Integration Engineer transitioning from middleware work
Software Engineer with exposure to RESTful services and cloud-native stacks

Advancement To:

Senior Java API Developer / Senior Backend Engineer
Tech Lead, API Platform Lead, or Principal Engineer
Solutions Architect or Engineering Manager focusing on API-first architectures

Lateral Moves:

DevOps / Platform Engineer (focus on CI/CD & orchestration)
Cloud Engineer (AWS/GCP/Azure specialist)
Full Stack Developer (adds frontend responsibilities)
Site Reliability Engineer focusing on production resilience

Core Responsibilities

Primary Functions

Design, develop, test and maintain scalable RESTful APIs and microservices using Java (8+), Spring Boot and Spring MVC, ensuring clean separation of concerns and adherence to API-first principles.
Define and own API contracts using OpenAPI/Swagger; produce and maintain accurate, human- and machine-readable API documentation for internal and external consumers.
Implement robust authentication and authorization mechanisms (OAuth2, OpenID Connect, JWT) and collaborate with security teams to validate API security posture and compliance.
Build fault-tolerant microservices using Spring Cloud components (Config, Netflix OSS alternatives, Circuit Breaker patterns) and design resilient communication patterns (retry, backoff, bulkhead).
Integrate APIs with relational (PostgreSQL, MySQL) and NoSQL (MongoDB, Cassandra, DynamoDB) datastores; design efficient data access layers and optimize queries for performance and scale.
Author comprehensive unit, integration, and contract tests (JUnit, Mockito, Spring Test, Pact) and participate in Test-Driven Development (TDD) where applicable to ensure high code quality.
Create and maintain CI/CD pipelines (Jenkins, GitLab CI, GitHub Actions) that automate build, test, containerization, and deployment to staging and production environments.
Containerize services with Docker and deploy to Kubernetes clusters (EKS/GKE/AKS) or managed container platforms, including writing Helm charts or Kubernetes manifests and managing resource limits.
Design and implement API gateway patterns and manage gateway configurations (AWS API Gateway, Kong, Apigee, or NGINX) for routing, authentication, rate-limiting, and analytics.
Collaborate with cross-functional product and engineering teams to translate business requirements into technical designs, estimate effort, and prioritize delivery in agile ceremonies.
Monitor and troubleshoot production systems using logging and observability tools (ELK/EFK, Prometheus, Grafana, Jaeger) and implement distributed tracing for latency analysis.
Conduct code reviews and enforce coding standards, clean code principles, and architectural best practices to reduce technical debt and improve maintainability.
Implement caching strategies (Redis, Memcached) and CDNs where appropriate to improve API response times and decrease backend load.
Profile and optimize JVM performance, garbage collection tuning, and memory usage to reduce latency and improve throughput under high concurrency.
Design API versioning and backward compatibility strategies to enable iterative product development without breaking existing clients.
Implement rate limiting, throttling, pagination, and graceful degradation patterns to manage throughput and protect services from overload.
Lead migration efforts from monolithic architectures to microservices, including decomposition planning, API gateway integration, and incremental rollouts.
Collaborate with QA and SRE to design production-ready deployment strategies, canary releases, blue/green deployments, and rollback procedures.
Drive observability and alerting improvements by defining meaningful metrics, SLAs, SLOs, and actionable alert thresholds for API performance and reliability.
Mentor junior engineers and onboard new team members on API design, Java best practices, microservices patterns, and cloud deployment workflows.
Participate in security reviews and threat modelling; remediate vulnerabilities discovered by automated scans and penetration testing.
Work with data engineering and analytics teams to instrument APIs for business metrics and gather usage telemetry for product decisions.
Maintain and update thorough system diagrams, runbooks, and operational documentation to support 24/7 reliability and on-call rotations.
Proactively identify architectural improvements, propose refactors, and lead small to medium service reengineering projects to reduce latency and costs.

Secondary Functions

Support ad-hoc data requests and exploratory data analysis.
Contribute to the organization's data strategy and roadmap.
Collaborate with business units to translate data needs into engineering requirements.
Participate in sprint planning and agile ceremonies within the data engineering team.
Assist product owners in defining acceptance criteria for API features and integration points.
Help maintain API developer portals, sample SDKs, and code examples to accelerate partner integration.
Participate in incident response and post-mortem activities; document root cause analysis and follow-up remediation tasks.
Evaluate and pilot new API tooling, observability platforms, or security technologies to improve developer productivity and service reliability.

Required Skills & Competencies

Hard Skills (Technical)

Java (8+) with strong fundamentals: OOP, concurrency, JVM internals, streams and functional patterns.
Spring Boot, Spring MVC, Spring Data, and Spring Security (practical experience building production services).
Microservices architecture design and hands-on experience with Spring Cloud or equivalent libraries for service discovery, configuration, and resilience.
RESTful API design principles, resource modeling, HATEOAS awareness, and proficiency with OpenAPI/Swagger specification.
API security: OAuth2, JWT, OpenID Connect and secure coding practices to prevent OWASP top vulnerabilities (e.g., injection, broken auth).
Containerization and orchestration: Docker, Kubernetes (managing pods, services, configmaps, secrets, Helm).
Cloud platform experience (AWS, GCP or Azure) including services for compute, managed databases, and networking.
Databases: SQL (PostgreSQL, MySQL) and NoSQL (MongoDB, DynamoDB); schema design and query tuning.
Messaging and event-driven systems: Kafka, RabbitMQ, or Amazon SQS/SNS for asynchronous integration patterns.
CI/CD pipeline tooling: Jenkins, GitLab CI, GitHub Actions, including automated testing and rollout strategies.
Source control and branching workflows: Git, pull requests, code review best practices.
Unit, integration and contract testing frameworks: JUnit, Mockito, Spring Test, Pact.
Observability and monitoring: ELK/EFK stack, Prometheus, Grafana, distributed tracing (Jaeger, Zipkin).
Performance tuning and profiling tools: VisualVM, YourKit, JFR, and experience tuning garbage collection.
API Gateway and management platforms: AWS API Gateway, Kong, Apigee, or NGINX configuration.

(At least 10 core technical skills expected for this role.)

Soft Skills

Strong verbal and written communication to clearly document APIs, design decisions, and runbooks.
Cross-functional collaboration: able to work with product managers, QA, SRE, security and business stakeholders.
Problem-solving and analytical mindset with a bias for data-driven decision-making.
Ownership and accountability for service reliability, technical debt reduction, and delivery timelines.
Mentoring and knowledge-sharing to uplift engineering practices across teams.
Time management and prioritization to balance feature delivery and operational responsibilities.
Adaptability to evolving requirements, tooling, and cloud-native patterns.
Customer-focused mindset: balance developer experience and API consumer needs with technical constraints.
Attention to detail for secure coding, thorough test coverage, and accurate documentation.

Education & Experience

Educational Background

Minimum Education:

Bachelor's degree in Computer Science, Software Engineering, Information Systems, Computer Engineering or equivalent practical experience.

Preferred Education:

Master’s degree in Computer Science, Software Engineering, or related technical discipline.
Certifications (optional but beneficial): AWS Certified Developer/Architect, Kubernetes (CKA/CKAD), Oracle Java Certification.

Relevant Fields of Study:

Computer Science
Software Engineering
Information Systems
Computer Engineering
Applied Mathematics / Data Science

Experience Requirements

Typical Experience Range: 3–7 years building backend systems, APIs, and production microservices in Java.

Preferred:

5+ years of professional Java backend development experience.
2+ years of demonstrable microservices and cloud-native architecture experience.
History of delivering high-throughput, low-latency APIs in production and contributing to platform-level decision making.